Longitudinal healthcare worker (HCW) cohorts throughout the COVID-19 pandemic provide a unique opportunity to study the relative contributions of various exposures to infection risk over time. This study aimed to examine how demographic, health, occupational, household and community factors influenced the SARS-CoV-2 infection risk in a cohort of HCWs in Southeastern Ontario, Canada, during the early pandemic and the Omicron waves. We compared the contribution of these factors to infection risk and explored the implications for future epidemic preparedness and the protection of HCWs.

We conducted a longitudinal analysis using data from a cohort of HCWs recruited from one acute care hospital and four long-term care homes. The analysis was divided into two periods: the initial phase of the pandemic (period #1) and the first three Omicron waves (period #2). We employed Poisson regression for period #1 and Cox regression for period #2 to examine associations of demographic factors (age, sex, ethnicity, migration status, income insufficiency), health factors (chronic conditions, smoking history, SARS-CoV-2 vaccination status), household factors (exposure to COVID-19), occupational factors (work role, exposure to COVID-19 patients, personal protective equipment access, aerosol-generating procedures) and community exposures (use of masks, distance, hand-washing) with SARS-CoV-2 infection.

At period #1, 17/208 (8.2%) HCWs reported having had SARS-CoV-2 infection. At period #2, 65/167 (38.3%) reported at least one SARS-CoV-2 infection. In period #1, factors associated with increased risk of infection included working in a long-term care home, exposure to more COVID-19-positive patients, working as a nurse or therapist, and inadequate use of personal protective equipment. In period #2, the hazard of infection was higher among HCWs who had COVID-19-infected children at home, whereas the use of protective measures in the community (maintaining social distance, mask-wearing) and receiving a vaccine booster were associated with reduced risk. Providing care to COVID-19 patients was not associated with the risk of acquiring SARS-CoV-2 infection at period #2.

During the Omicron wave, community and household exposures, but not occupational exposure to COVID-19 cases, were the primary factors contributing to infection risk in HCWs. This contrasts with the early waves of the pandemic where occupational exposures played a significant role. These findings may be explained by the effectiveness of institutional interventions in reducing the risk of SARS-CoV-2 transmission in healthcare settings, alongside the failure of community-level interventions to mitigate risk during the Omicron period.

Despite the global implementation of COVID-19 mitigation measures, the disease continues to maintain transmission. Although mask wearing became one of the key measures for preventing the transmission of COVID-19 early in the pandemic period, many countries have relaxed the mandatory or recommended wearing of masks. The objective of the present study was to estimate the epidemiological impact of removing the mask-wearing recommendation in Japan. We developed a model to assess the consequences of declining mask-wearing coverage after the government revoked its recommendation in February 2023. The declining mask-wearing coverage was estimated using serial cross-sectional data, and a mathematical model was devised to determine the age-specific incidence of COVID-19 using the observed case count in Tokyo from week of October 3, 2022 to October 30, 2023. We explored model-based counterfactual scenarios to measure hypothetical situations in which the mask-wearing coverage decreases or increases relative to the observed coverage. The results show that mask-wearing coverage declined from 97% to 69% by the week of October 30, 2023, and that if the mask-wearing recommendation had continued, 427 lives could have been saved in Tokyo. If the mask-wearing coverage had declined to 25% of the observed level, the model suggests there might have been 1587 additional deaths. Thus, revoking the mask-wearing recommendation had a substantial epidemiological impact. In future pandemics, our proposed approach could provide a real-time quantification of the effects of relaxing countermeasures.

To clarify the infection control measures required in the event of a new infectious disease outbreak, we conducted a questionnaire survey on the infection control measures implemented against coronavirus disease 2019 (COVID-19).

An invitation to participate in this survey was sent to the heads of 2689 facilities affiliated with the members of the Japanese Society for Infection Prevention and Control in February 2023, requesting responses to the online survey using Google Forms by March 2023.

Six hundred and forty-five facilities, including 20 clinics and 625 hospitals, participated in the survey. This survey revealed that various infection control measures were implemented, including universal masking in the non-COVID-19 ward (96.5 %), screening tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on scheduled admission (89.0 %), SARS-CoV-2 tests (98.7 %), and isolation in private rooms (76.5 %) for inpatients with fever. However, nosocomial infections and clusters of COVID-19 occurred in 94.4 % and 90.9 % of cases during the investigation period, respectively. One of the reasons for these results is that healthcare personnel (HCP) and patients were common index cases of nosocomial infections, and the most common cause of clusters was the work of symptomatic HCPs. These results suggest that HCPs should understand that they can be index cases or spreaders. On the other hand, the most common support from external facilities was healthcare centers, followed by physicians or nurses from other hospitals.

In response to the emergence of infections, it is important to consider implementing infection control measures for HCPs and patients.

Assess healthcare workers' (HCW) attitudes toward universal masking, and gowns and gloves used as part of transmission-based precautions.

Cross-sectional survey.

Academic, tertiary care medical center in Baltimore, Maryland.

HCW who work in patient care areas and have contact with patients.

In May 2023, a 15-question web-based survey was distributed by the hospital's communications team via email. The survey contained questions to assess HCW perceptions of universal masking policies prior to the availability of COVID-19 vaccines and at the time of the survey, and the use of gowns and gloves for transmission-based precautions. Descriptive statistics were used to summarize data. Differences in agreement with universal masking over time, level of agreement with gown and glove policies, and with all PPE types across respondent characteristics were assessed.

257 eligible respondents completed the survey. Nurses and patient care technicians (43%) and providers (17%) were the most commonly reported roles. Agreement with universal mask use decreased from 84% early in the pandemic to 55% at the time of the survey. 70% and 72% of HCW agreed masks protect themselves and others, respectively. 63% expressed any level of annoyance with mask wearing, the most often due to communication challenges or physical discomfort. 75% agreed with gown use for antibiotic-resistant bacteria compared with 90% for glove use.

The majority of HCW agree with the use of PPE to prevent pathogen transmission in the healthcare setting. Agreement with universal mask use for patient care shifted during the COVID-19 pandemic.

The use of non-pharmacological preventive measures during the COVID-19 pandemic has helped to reduce the incidence of multiple airborne or contact diseases. The objective of this paper was to evaluate the impact that all preventive measures have had on the transmission of different microorganisms, both by respiratory and contact transmission.

We compared the incidence of different infectious episodes coded with the CIAP-2 code (International Classification of Primary Care second edition of the WONCA International Classification Committee) collected from the computerized history of primary care, both with respiratory tract and digestive tract involvement, in the period from March 2018 to February 2020 (pre-pandemic period) and from March 2020 to February 2022 (pandemic period). The data corresponded to the entire region, with an estimated average population for the four years of 650,000 people. The statistical treatment of the data consisted of a descriptive analysis with the calculation of absolute values and percentages. Rates were calculated and compared using data provided by the National Institute of Statistics as a denominator. The P was obtained by statistical comparison by the exact method. A comparison of rates was made.

The incidence in the number of CIAP-2 episodes studied, both corresponding to respiratory and gastrointestinal pathologies, comparing the period March 2018-February 2020 with the period March 2020-February 2022 decreased by 65.81%, from 534,439 cases to 182,707.

The preventive measures applied during the pandemic produce a significant decrease in pathology involving the respiratory or the digestive tract.

The outbreak of the COVID-19 pandemic led to a sharp increase in disposable surgical mask usage. Discarded masks can release microplastic and cause environmental pollution. Since masks have become a daily necessity for protection against virus infections, it is necessary to review the usage and disposal of masks during the pandemic for future management. In this study, we constructed a dynamic model by introducing related parameters to estimate daily mask usage in 214 countries from January 22, 2020 to July 31, 2022. And we validated the accuracy of our model by establishing a dataset based on published survey data. Our results show that the cumulative mask usage has reached 800 billion worldwide, and the microplastics released from discarded masks due to mismanagement account for 3.27% of global marine microplastic emissions in this period. Furthermore, we illustrated the response relationship between mask usage and the infection rates. We found a marginally significant negative correlation existing between the mean daily per capita mask usage and the rate of cumulative confirmed cases within the range of 25% to 50%. This indicates that if the rate reaches the specified threshold, the preventive effect of masks may become evident.

This study aims to investigate international measures for pandemic control in the workplace based on guidelines from international organizations to learn from their experiences.

We conducted a qualitative study using content analysis. The search method involved reviewing published guidelines on preventing and responding to the COVID-19 pandemic in workplaces. After the screening process, ten guidelines were included in the content analysis. During the analysis, 200 meaning codes, 49 subcategories, and eleven categories were identified. Trustworthiness criteria were utilized to ensure the accuracy and strength of the findings.

Eleven categories of international content during the COVID-19 pandemic were legal requirements and duties of employees and employers, structural and program changes, risk assessment, risk communication, information and training, internal and external consultation and cooperation, provision of facilities and tools for workplace hygiene, special conditions, special groups, closing and reopening workplaces, reducing contact and exposure and mental health.

Protecting employees during a pandemic requires a multifaceted approach and strong advocacy. The operational plan for pandemic control should be developed based on the level of risk, with support tailored to employees' conditions and needs. Cooperation among international organizations is essential to develop a standardized plan and issue comprehensive guidelines in response to health emergencies with a global perspective and local implementation, drawing from the lessons learned during the COVID-19 pandemic.

Determine SARS-CoV-2 IgG antibody incidence over time in unvaccinated pediatric healthcare workers (pHCWs).

A prospective longitudinal cohort of unvaccinated pHCWs measuring the incidence of new infection after initial prevalence was established at 4.1% with seropositive predominance in emergency department (ED)-based pHCWs. Serum samples were collected at follow-up visits to detect new SARS-CoV-2 seropositivity. Univariate analysis was performed to estimate different incidence rates between participant demographics, job, employment location, and community risk factors. Anxiety levels about COVID-19 were collected. SARS-CoV-2 antibody decay postinfection and neutralization antibodies were evaluated. Log-linear Poisson regression models were used to estimate incidence.

Of 642 initially enrolled, 390 pHCWs presented for at least one follow-up serology test after baseline analysis. The incidence of SARS-CoV-2 seropositivity was 8.2%. The seropositive cohort, like the negative one, consisted mainly of females in non-ED settings and nonphysician roles. There were no statistically significant differences in incidence across variables. Seropositive participants dropped antibody titers by 50% at 3 months. Neutralization antibodies correlated to SARS-CoV-2 binding antibodies (r = 0.43, P < 0.0001).

The incidence of seropositivity was 8.2%. Although seropositivity was higher among ED staff during the early stages of the pandemic, this difference declined over time, likely due to the universal adoption of personal protective equipment.

The COVID-19 pandemic resulted in rapid changes aimed at reducing disease transmission in maternity services in Australia. An increase in personal protective equipment (PPE) in the clinical and community setting was a key strategy. There was variation in the type of PPE and when it was to be worn in clincial practice.

This paper reports on Australian midwives' experiences of PPE during the pandemic.

This sequential mixed methods study was part of the Birth in the Time of COVID-19 (BITTOC 2020) study. Data were obtained from in-depth semi-structured interviews with midwives in 2020 followed by a national survey undertaken at two time points (2020 and 2021). Qualitative open-text survey responses and interview data were analysed using content analysis.

16 midwives were interviewed and 687 midwives provided survey responses (2020 n = 477, 2021 n = 210). Whilst midwives largley understood the need for increased PPE, and were mainly happy with this, as it was protective, they reported a number of concerns. These included: inconsistency with PPE type, use, availability, quality, fit and policy; the impact of PPE on the physical and psychological comfort of midwives; and the barriers PPE use placed on communication and woman centred care. This at times resulted in midwives working outside of policy.

These findings highlight the need for future comprehensive pandemic preparedness that ensures policy and procedure recommendations are consistent and PPE is available, of approriate quality, and individually fitted in order to ensure that Australian maternity services are well placed to manage future pandemics.

In the initial phase of the SARS-CoV-2 pandemic, masking has been widely accepted in healthcare institutions to mitigate the risk of healthcare-associated infection. Evidence, however, is still scant and the role of masks in preventing healthcare-associated SARS-CoV-2 acquisition remains unclear.We investigated the association of variation in institutional mask policies with healthcare-associated SARS-CoV-2 infections in acute care hospitals in Switzerland during the BA.4/5 2022 wave.

SARS-CoV-2 infections in hospitalized patients between June 1 and September 5, 2022, were obtained from the "Hospital-based surveillance of COVID-19 in Switzerland"-database and classified as healthcare- or community-associated based on time of disease onset. Institutions provided information regarding institutional masking policies for healthcare workers and other prevention policies. The percentage of healthcare-associated SARS-CoV-2 infections was calculated per institution and per type of mask policy. The association of healthcare-associated SARS-CoV-2 infections with mask policies was tested using a negative binominal mixed-effect model.

We included 2'980 SARS-CoV-2 infections from 13 institutions, 444 (15%) were classified as healthcare-associated. Between June 20 and June 30, 2022, six (46%) institutions switched to a more stringent mask policy. The percentage of healthcare-associated infections subsequently declined in institutions with policy switch but not in the others. In particular, the switch from situative masking (standard precautions) to general masking of HCW in contact with patients was followed by a strong reduction of healthcare-associated infections (rate ratio 0.39, 95% CI 0.30-0.49). In contrast, when compared across hospitals, the percentage of health-care associated infections was not related to mask policies.

Our findings suggest switching to a more stringent mask policy may be beneficial during increases of healthcare-associated SARS-CoV-2 infections at an institutional level.

COVID-19, caused by the SARS-CoV-2 virus, is a highly pathogenic emerging infectious disease. Healthcare personnel (HCP) are presumably at higher risk of acquiring emerging infections because of occupational exposure. The prevalence of COVID-19 in HCP is unknown, particularly in low- to middle-income countries like El Salvador. The goal of this study was to determine the seroprevalence of anti-SARS-CoV-2 antibodies among HCP in El Salvador just prior to vaccine rollout in March 2021. We evaluated 2176 participants from a nationally representative sample of national healthcare institutions. We found 40.4% (n = 880) of the study participants were seropositive for anti-spike protein antibodies. Significant factors associated with infection included younger age; living within the central, more populated zone of the country; living in a larger household (≥7 members); household members with COVID-19 or compatible symptoms; and those who worked in auxiliary services (i.e., housekeeping and food services). These findings provide insight into opportunities to mitigate SARS-CoV-2 risk and other emerging respiratory pathogens in HCP in El Salvador.

Infection prevention (IP) measures are designed to mitigate the transmission of pathogens in healthcare. Using large-scale viral genomic and social network analyses, we determined if IP measures used during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic were adequate in protecting healthcare workers (HCWs) and patients from acquiring SARS-CoV-2.

We performed retrospective cross-sectional analyses of viral genomics from all available SARS-CoV-2 viral samples collected at UC San Diego Health and social network analysis using the electronic medical record to derive temporospatial overlap of infections among related viromes and supplemented with contact tracing data. The outcome measure was any instance of healthcare transmission, defined as cases with closely related viral genomes and epidemiological connection within the healthcare setting during the infection window. Between November 2020 through January 2022, 12 933 viral genomes were obtained from 35 666 patients and HCWs.

Among 5112 SARS-CoV-2 viral samples sequenced from the second and third waves of SARS-CoV-2 (pre-Omicron), 291 pairs were derived from persons with a plausible healthcare overlap. Of these, 34 pairs (12%) were phylogenetically linked: 19 attributable to household and 14 to healthcare transmission. During the Omicron wave, 2106 contact pairs among 7821 sequences resulted in 120 (6%) related pairs among 32 clusters, of which 10 were consistent with healthcare transmission. Transmission was more likely to occur in shared spaces in the older hospital compared with the newer hospital (2.54 vs 0.63 transmission events per 1000 admissions, P < .001).

IP strategies were effective at identifying and preventing healthcare SARS-CoV-2 transmission.

Inpatient behavioral health units (BHUs) had unique challenges in implementing interventions to mitigate coronavirus disease 2019 (COVID-19) transmission, in part due to socialization in BHU settings. The objective of this study was to identify the transmission routes and the efficacy of the mitigation strategies employed during a COVID-19 outbreak in an inpatient BHU during the Omicron surge from December 2021 to January 2022.

An outbreak investigation was performed after identifying 2 COVID-19-positive BHU inpatients on December 16 and 20, 2021. Mitigation measures involved weekly point prevalence testing for all inpatients, healthcare workers (HCWs), and staff, followed by infection prevention mitigation measures and molecular surveillance. Whole-genome sequencing on a subset of COVID-19-positive individuals was performed to identify the outbreak source. Finally, an outbreak control sustainability plan was formulated for future BHU outbreak resurgences.

We identified 35 HCWs and 8 inpatients who tested positive in the BHU between December 16, 2021, and January 17, 2022. We generated severe acute respiratory coronavirus virus 2 (SARS-CoV-2) genomes from 15 HCWs and all inpatients. Phylogenetic analyses revealed 3 distinct but genetically related clusters: (1) an HCW and inpatient outbreak likely initiated by staff, (2) an HCW and inpatient outbreak likely initiated by an inpatient visitor, and (3) an HCW-only cluster initiated by staff.

Distinct transmission clusters are consistent with multiple, independent SARS-CoV-2 introductions with further inpatient transmission occurring in communal settings. The implemented outbreak control plan comprised of enhanced personal protective equipment requirements, limited socialization, and molecular surveillance likely minimized disruptions to patient care as a model for future pandemics.

At the beginning of the COVID-19 pandemic, whether performing CPR on patients with COVID-19 would be effective or increase COVID-19 transmission to health care workers was unclear.

Did the prevalence of do-not-resuscitate (DNR) orders by COVID-19 status change over the first year of the pandemic as risks such as COVID-19 transmission to health care workers improved?

This cross-sectional study assessed DNR orders for all adult patients admitted to ICUs at two academic medical centers in Chicago, IL, between April 2020 and April 2021. DNR orders by COVID-19 status were assessed using risk-adjusted mixed-effects logistic regression and propensity score matching by patient severity of illness.

The study population of 3,070 critically ill patients were 46% Black, 53% male, with median age (interquartile range [IQR]) 63 (50-73) years. Eighteen percent were COVID-19 positive and 27% had a DNR order. Black and Latinx patients had higher absolute rates of DNR orders than White patients (30% vs 29% vs 23%; P = .006). After adjustment for patient characteristics, illness severity, and hospital location, DNR orders were more likely in patients with COVID-19 in the nonpropensity score-matched (n = 3,070; aOR, 2.01; 95% CI, 1.64-2.38) and propensity score-matched (n = 1,118; aOR, 1.91; 95% CI, 1.45-2.52) cohorts. The prevalence of DNR orders remained higher for patients with COVID-19 than patients without COVID-19 during all months of the study period (difference in prevalence over time, P = .751).

In this multihospital study, DNR orders remained persistently higher for patients with COVID-19 vs patients without COVID-19 with similar severity of illness during the first year of the pandemic. The specific reasons why DNR orders remained persistently elevated for patients with COVID-19 should be assessed in future studies, because these changes may continue to affect COVID-19 patient care and outcomes.

Background: Mask use is recommended to reduce the transmission of severe acute respiratory syndrome coronavirus 2. The safety of mask use in adults and children with asthma is unknown. Objective: The objective of this study is to evaluate the effect of mask use on peripheral oxygen saturation (SpO₂) in those with and those without asthma. Methods: A two-stage cross-sectional study was performed. In the first stage, the SpO₂ concentration in adults and children with and without asthma was measured with the adults and children at rest during mask use. In the second stage, children years 6-17 performed a 6-minute walk test while wearing masks. The SpO₂ concentration was measured before the exercise and at 3 and 6 minutes into exercise. Subjective dyspnea was evaluated by using the Pediatric Dyspnea Scale (PDS). Results: In the first stage, SpO₂ levels in 393 subjects were analyzed. In the second stage, 50 pediatric subjects were included, 25 with and 25 without asthma. There was no difference in SpO₂ levels between those with and those without asthma in adults and children wearing masks while at rest, with median SpO₂ 98% in both groups. There was no difference in oxygen saturation or reported level of dyspnea between the children with asthma and children without asthma performing the 6-minute walk test while wearing masks. Median SpO₂ levels were at or near 99% in the asthma and non-asthma groups at all time points. Median PDS scores were similar between the asthma and non-asthma groups. Conclusion: Mask use did not affect SpO₂ in adults and children at rest or in children performing low-to-moderate intensity exercise. These findings were consistent in those with and without asthma.

The efficacy of face masking for the public is not convincing to prevent the transmission of respiratory tract viruses such as SARS-CoV-2 when the criteria of evidence-based medicine are applied. This finding is mainly explained by the results from randomized-controlled trials (RCTs) when a high prevalence of the infection and a high compliance in mask wearing was assured. Throughout these studies no significant protective effect was observed. Observational studies with surgical masks describe a significant protective effect, but are prone to confounders such as physical distance. Respirators do not provide an additional health benefit compared to surgical or medical masks (RCTs). Community masks can even increase the risk of infection (RCTs). Based on the categories of evidence-based medicine, the efficacy results can best be categorized as conflicting evidence. Many relevant adverse events are described when masks are worn for hours such as dyspnea (12.2-52.8%), headache (3.9-73.4%), pruritus (0.0-60.0%), and skin reactions (0.0-85.0%). Their frequency is often higher with respirators. In future pandemics, masks should only be recommended or mandated for settings in which a clinically relevant health benefit can be expected, defined as the prevention of severe, critical or fatal disease, that clearly outweighs the expectable associated adverse reactions.

We compared the individual-level risk of hospital-onset infections with multidrug-resistant organisms (MDROs) in hospitalized patients prior to and during the coronavirus disease 2019 (COVID-19) pandemic. We also quantified the effects of COVID-19 diagnoses and intrahospital COVID-19 burden on subsequent MDRO infection risk.

Multicenter, retrospective, cohort study.

Patient admission and clinical data were collected from 4 hospitals in the St. Louis area.

Data were collected for patients admitted between January 2017 and August 2020, discharged no later than September 2020, and hospitalized ≥48 hours.

Mixed-effects logistic regression models were fit to the data to estimate patients' individual-level risk of infection with MDRO pathogens of interest during hospitalization. Adjusted odds ratios were derived from regression models to quantify the effects of the COVID-19 period, COVID-19 diagnosis, and hospital-level COVID-19 burden on individual-level hospital-onset MDRO infection probabilities.

We calculated adjusted odds ratios for COVID-19-era hospital-onset Acinetobacter spp., P. aeruginosa and Enterobacteriaceae spp infections. Probabilities increased 2.64 (95% confidence interval [CI], 1.22-5.73) times, 1.44 (95% CI, 1.03-2.02) times, and 1.25 (95% CI, 1.00-1.58) times relative to the prepandemic period, respectively. COVID-19 patients were 4.18 (95% CI, 1.98-8.81) times more likely to acquire hospital-onset MDRO S. aureus infections.

Our results support the growing body of evidence indicating that the COVID-19 pandemic has increased hospital-onset MDRO infections.

The global health pandemic caused by the SARS-coronavirus 2 (COVID-19) has led to the adoption of facemasks as a necessary safety precaution. Depending on the level of risk for exposure to the virus, the facemasks that are used can vary. The aim of this study was to examine the effect of different types of facemasks, typically used by healthcare professionals and the public during the COVID-19 pandemic, on measures of voice.

Nineteen adults (ten females, nine males) with a normal voice quality completed sustained vowel tasks. All tasks were performed for each of the six mask conditions: no mask, cloth mask, surgical mask, KN95 mask and, surgical mask over a KN95 mask with and without a face shield. Intensity measurements were obtained at a 1ft and 6ft distance from the speaker with sound level meters. Tasks were recorded with a 1ft mouth-to-microphone distance. Acoustic variables of interest were fundamental frequency (F0), and formant frequencies (F1, F2) for /a/ and /i/ and smoothed cepstral peak prominence (CPPs) for /a/.

Data were analyzed to compare differences between sex and mask types. There was statistical significance between males and females for intensity measures and all acoustic variables except F2 for /a/ and F1 for /i/. Few pairwise comparisons between masks reached significance even though main effects for mask type were observed. These are further discussed in the article.

The masks tested in this study did not have a significant impact on intensity, fundamental frequency, CPPs, first or second formant frequency compared to voice output without a mask. Use of a face shield seemed to affect intensity and CPPs to some extent. Implications of these findings are discussed further in the article.

This rapid systematic review of evidence asks whether (i) wearing a face mask, (ii) one type of mask over another and (iii) mandatory mask policies can reduce the transmission of SARS-CoV-2 infection, either in community-based or healthcare settings. A search of studies published 1 January 2020-27 January 2023 yielded 5185 unique records. Due to a paucity of randomized controlled trials (RCTs), observational studies were included in the analysis. We analysed 35 studies in community settings (three RCTs and 32 observational) and 40 in healthcare settings (one RCT and 39 observational). Ninety-five per cent of studies included were conducted before highly transmissible Omicron variants emerged. Ninety-one per cent of observational studies were at 'critical' risk of bias (ROB) in at least one domain, often failing to separate the effects of masks from concurrent interventions. More studies found that masks (n = 39/47; 83%) and mask mandates (n = 16/18; 89%) reduced infection than found no effect (n = 8/65; 12%) or favoured controls (n = 1/65; 2%). Seven observational studies found that respirators were more protective than surgical masks, while five found no statistically significant difference between the two mask types. Despite the ROB, and allowing for uncertain and variable efficacy, we conclude that wearing masks, wearing higher quality masks (respirators), and mask mandates generally reduced SARS-CoV-2 transmission in these study populations. This article is part of the theme issue 'The effectiveness of non-pharmaceutical interventions on the COVID-19 pandemic: the evidence'.

In an effort to decrease transmission during the first years of the COVID-19 pandemic, public health officials encouraged masking, social distancing, and working from home, and restricted travel. However, many studies of the effectiveness of these measures had significant methodologic limitations. In this analysis, we used data from the TrackCOVID study, a longitudinal cohort study of a population-based sample of 3846 adults in the San Francisco Bay Area, to evaluate the association between self-reported protective behaviors and incidence of SARS-CoV-2 infection.

Participants without SARS-CoV2 infection were enrolled from August to December 2020 and followed monthly with testing and surveys (median of four visits).

A total of 118 incident infections occurred (3.0% of participants). At baseline, 80.0% reported always wearing a mask; 56.0% avoided contact with nonhousehold members some/most of the time; 9.6% traveled outside the state; and 16.0% worked 20 or more hours per week outside the home. Factors associated with incident infection included being Black or Latinx, having less than a college education, and having more household residents. The only behavioral factor associated with incident infection was working outside the home (adjusted hazard ratio 1.62, 95% confidence interval 1.02-2.59).

Focusing on protecting people who cannot work from home could help prevent infections during future waves of COVID-19, or future pandemics from respiratory viruses. This focus must be balanced with the known importance of directing resources toward those at risk of severe infections.

Three years after the beginning of the COVID-19 pandemic, better knowledge on the transmission of respiratory viral infections (RVI) including the contribution of asymptomatic infections encouraged most healthcare centers to implement universal masking. The evolution of the SARS-CoV-2 epidemiology and improved immunization of the population call for the infection and prevention control community to revisit the masking strategy in healthcare. In this narrative review, we consider factors for de-escalating universal masking in healthcare centers, addressing compliance with the mask policy, local epidemiology, the level of protection provided by medical face masks, the consequences of absenteeism and presenteeism, as well as logistics, costs, and ecological impact. Most current national and international guidelines for mask use are based on the level of community transmission of SARS-CoV-2. Actions are now required to refine future recommendations, such as establishing a list of the most relevant RVI to consider, implement reliable local RVI surveillance, and define thresholds for activating masking strategies. Considering the epidemiological context (measured via sentinel networks or wastewater analysis), and, if not available, considering a time period (winter season) may guide to three gradual levels of masking: (i) standard and transmission-based precautions and respiratory etiquette, (ii) systematic face mask wearing when in direct contact with patients, and (iii) universal masking. Cost-effectiveness analysis of the different strategies is warranted in the coming years. Masking is just one element to be considered along with other preventive measures such as staff and patient immunization, and efficient ventilation.

To assess the added risk of acute endophthalmitis after intravitreal injections associated with the widespread use of face masks during the COVID-19 pandemic.

In this retrospective, single-center study, records of patients with acute endophthalmitis following intravitreal bevacizumab (IVB) injections during the pre-COVID era-that is, March 1st , 2013 to October 31st , 2019 -and the COVID-19 era-that is, March 1st , 2020 to April 1st , 2021 -were reviewed and compared.

A total of 28,085 IVB injections were performed during the pre-COVID era; nine eyes of nine patients developed acute post-IVB endophthalmitis in this era, giving an overall incidence of 0.032% (3.2 in 10,000 injections). In the COVID era, 10,717 IVB injections were performed; four eyes of four patients developed acute post-IVB endophthalmitis in this era, giving an overall incidence of 0.037% (3.7 in 10,000 injections). The incidences of post-IVB endophthalmitis during these two eras were not statistically significantly different (P = 0.779).

Face masking protocols seem unlikely to impose any additional risk of post-IVB endophthalmitis.

Wearing masks could still be one of the few non-pharmaceutical interventions for controlling the pandemic. There are people who wear them and people who don't, but this framing is overly simplistic. We aim to chart the contradictions in attitudes and behavior regarding mask wearing and describe the messaging challenge that these generate.

Our data come from a survey administered to a nationally representative sample of 2000 respondents from the YouGov panel of US households in August-September 2020.

Respondents were asked whether they wear a facemask when they go outside their home since the COVID-19 epidemic began and whether they support or oppose your municipal government passing mask wearing regulation. We also collected respondents' demographic and economic characteristics, knowledge regarding the facts of COVID-19 and political ideology.

A substantial majority of Americans (60%) both favor a masking requirement and are themselves wearing masks, while 13% oppose a mask mandate and do not wear masks. In contrast, 17% of Americans oppose a mask mandate but are currently wearing one, while 10% do not wear a mask but favor a mask mandate. These two groups are distinctively different from one another and the other groups in their socioeconomic characteristics, risk perception and political beliefs.

Our study offers a better understanding of the mismatch between mask wearing behavior and attitude toward the mask mandate, which will help the public health authorities to devise policies regarding mask wearing as an effective intervention to manage the pandemic.

Professional soccer athletes are at risk of acquiring severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). United States Major League Soccer (MLS) uses protocol-based SARS-CoV-2 testing for identification of individuals with coronavirus disease 2019.

Per MLS protocol, fully vaccinated players underwent SARS-CoV-2 real-time polymerase chain reaction testing weekly; unvaccinated players were tested every other day. Demographic and epidemiologic data were collected from individuals who tested positive, and contact tracing was performed. Whole genome sequencing (WGS) was performed on positive specimens, and phylogenetic analyses were used to identify potential transmission patterns.

In the fall of 2021, all 30 players from 1 MLS team underwent SARS-CoV-2 testing per protocol; 27 (90%) were vaccinated. One player who had recently traveled to Africa tested positive for SARS-CoV-2; within the following 2 weeks, 10 additional players and 1 staff member tested positive. WGS yielded full genome sequences for 10 samples, including 1 from the traveler. The traveler's sample was Delta sublineage AY.36 and was closely related to a sequence from Africa. Nine samples yielded other Delta sublineages including AY.4 (n = 7), AY.39 (n = 1), and B.1.617.2 (n = 1). The 7 AY.4 sequences clustered together; suggesting a common source of infection. Transmission from a family member visiting from England to an MLS player was identified as the potential index case. The other 2 AY.4 sequences differed from this group by 1-3 nucleotides, as did a partial genome sequence from an additional team member.

WGS is a useful tool for understanding SARS-CoV-2 transmission dynamics in professional sports teams.

This study aimed to develop a unique online infection prevention and control (IPC) training on Covid-19 for healthcare workers in psychiatric institutes in Japan and to examine its efficacy based on its impact on the knowledge, attitude, and confidence about IPC for Covid-19 among the healthcare workers.

This quasi-experimental study was conducted using online training on Covid-19 IPC for healthcare workers in various psychiatric institutes from April 2021 to March 2022. An online training video on Covid-19 IPC was developed. Voluntary healthcare workers in psychiatric institutes located in five prefectures in Japan were recruited to participate in this training. The participants then completed 30 min of online training and surveys about knowledge, attitude, and confidence were conducted pre, post, and three months after the training. The video training and surveys were contextually validated by the experts, but not by any previous study.

A total of 224 participants were included, of which 108 (54.0%) were men. The mean (standard deviation (SD)) age and the mean occupational experience were 47.4 (9.5) and 18.0 (12.6) years, respectively. Among the participants, 190 (84.8%) completed the post-training, and 131 (58.5%) completed the three-month-later training surveys. The total score on the quizzes in the post-training (+ 31.1%, SD 15.7, p-value < 0.01) and three-month-later training (+ 14.9%, SD 16.8, p-value < 0.01) surveys had significantly increased from that in the pre-training survey. In contrast, the total score in the three-month-later training had significantly decreased from that in the post-training survey (-16.1%, SD 16.7, p-value < 0.01).

Thirty minutes of online training about IPC for Covid-19 had improved knowledge, confidence, and attitude among psychiatric healthcare workers. Regular online training would help in preventing the transmission or formation of clusters of Covid-19 in psychiatric healthcare institutes.

Background The Unity® Consortium surveyed teens and parents and guardians of teens across the country at three distinct time points or waves during the COVID-19 pandemic to assess participant attitudes and beliefs regarding COVID-19 mitigation guidelines, such as mask-wearing and physical distancing. Methodology A third-party market research company conducted 15-minute, online surveys from nationally representative panels. Surveys were conducted at three distinct time points or waves (August 2020, February 2021, and June 2021) with 300 teens aged 13-18 years in each wave and 593/531/500 parents and guardians of teens aged 13-18 years in each wave, respectively. Participants responded using a five-point Likert scale (strongly agree to strongly disagree) on their COVID-19 experiences, including the perceived importance of strictly following mask-wearing and/or social distancing guidelines and the perceived effectiveness of mask-wearing and social distancing in preventing the spread of COVID-19. Data were analyzed for differences across waves and demographic variables. Statistical analyses included frequencies, analysis of variance (ANOVA), and t-tests/z-tests. Results While significantly more parents and teens in Waves 2 and 3 knew someone who was hospitalized or died due to COVID-19 compared to Wave 1, significantly fewer in Wave 3 reported experiencing a lot or some stress and worry regarding the pandemic. By Wave 3, 58% of teens and 56% of parents had received at least one dose of a COVID-19 vaccine. Despite changes in experiences over time, a significant majority of parents and teens consistently agreed on the importance and effectiveness of social distancing and masking guidelines against the spread of COVID-19. In Wave 3, the demographic variables significantly associated with agreement on importance included race (Black (92%) > White (80%)), community type (urban (91%) > suburban (79%) and rural (73%)), and positive vaccination status of parents and teens (92%/89%) > not vaccinated (73%/73%), respectively). The demographic variables significantly associated with agreement on effectiveness included race (Black (91%) > White (81%)), community type (urban (89%) > suburban (83%) and rural (71%)), and positive vaccination status of parents and teens (94%/90% > not vaccinated (72%/70%), respectively). Conclusions This study into the perceived importance and perceived effectiveness of mitigation strategies during the COVID-19 pandemic revealed differences in attitudes among sociodemographic groups. Understanding these differences can help shape how adherence to public health guidelines in a pandemic is promoted.

The COVID-19 pandemic accelerated the spread of misinformation worldwide. The purpose of this study was to explore perceptions of misinformation and preferred sources of obtaining COVID-19 information from those living in Canada. In particular, we sought to explore the perceptions of East Asian individuals in Canada, who experienced stigma related to COVID-19 messaging.

We conducted a qualitative thematic analysis study. Interviews were offered in English, Mandarin and Cantonese. Interviewers probed for domains related to knowledge about COVID-19, preferred sources of information, perceived barriers and facilitators of misinformation, and preferences for communication during a health emergency. Interviews were recorded, translated, transcribed verbatim and analyzed using a framework approach. Transcripts were independently double-coded until > 60% agreement was reached. This study received research ethics approval.

Fifty-five interviews were conducted. The majority of participants were women (67%); median age was 52 years. 55% of participants were of East-Asian descent. Participants obtained information about COVID-19 from diverse English and non-English sources including news media, government agencies or representatives, social media, and personal networks. Challenges to seeking and understanding information included: encountering misinformation, making sense of evolving or conflicting public health guidance, and limited information on topics of interest. 65% of participants reported encountering COVID-19  misinformation. East Asian participants called on government officials to champion messaging to reduce stigmatizing and racist rhetoric and highlighted the importance of having accessible, non-English language information sources. Participants provided recommendations for future public health communications guidance during health emergencies, including preferences for message content, information messengers, dissemination platforms and format of messages. Almost all participants preferred receiving information from the Canadian government and found it helpful to utilize various mediums and platforms such as social media and news media for future risk communication, urging for consistency across all platforms.

We provide insights on Canadian experiences navigating COVID-19 information, where more than half perceived encountering misinformation on platforms when seeking COVID-19 information . We provide recommendations to inform public health communications during future health emergencies.

Airborne aerosol transmission, an established mechanism of SARS-CoV-2 spread, has been successfully mitigated in the health care setting through the adoption of universal masking. Upper airway endoscopy, however, requires direct access to the face, thereby potentially exposing the clinic environment to infectious particles. This study quantifies aerosol production during rigid nasal endoscopy (RNE) and RNE with debridement (RNED) as compared with intubation, a posited gold standard aerosol-generating procedure.

Prospective cross-sectional study.

Subspecialty single-center clinic and surgical study.

Three aerosol detectors (NANOSCAN-3910, OPS-3330, and APS-3321) with a particle size sensitivity of 10 to 20,000 nm were utilized to detect particulate production during the clinical care of 209 patients undergoing RNE/RNED and 25 patients undergoing intubation.

RNE and RNED produced statistically significant particles over baseline in 29.3% and 51.0% of subjects (P = .003-.049 and .002-.047, respectively). Intubation produced statistically significant particles in 31.2% (P = .001-.015). The mean ± SD particle diameter in all tests was 69.9 ± 10.5 nm with 99.7% <300 nm. There were no statistical differences in particle production among RNE, RNED, and intubation. The presence of concomitant cough, sneeze, or prolonged speech similarly did not significantly affect particle production during any procedure.

Instrumentation of nasal airway produces airborne aerosols to a similar degree of those seen during intubation, independent of reactive patient behaviors such as cough or sneeze. These data suggest that an improved understanding is necessary of both the definition of an aerosol-generating procedure and the functional consequences of procedural aerosol generation in clinical settings.

Wearing a face mask is a primary public health method to reduce SARS-CoV-2 transmission.

We performed a nested case-control analysis within the North Carolina COVID-19 Community Research Partnership (NC-CCRP) of adults who completed daily surveillance surveys, April 2020 - February 2022. We assessed the association between self-reported mask wearing behavior during nonhousehold interactions and COVID-19 infection during 3 pandemic periods using conditional logistic regression models of risk of infection that were adjusted for demographics, vaccination status, and recent known exposure to COVID-19.

Among 3,901 cases and 27,813 date-matched controls, there was a significant interaction between mask use and time period (P < .001). Prior to July 2021, the odds of a reported infection were 66% higher (aOR = 1.66, 95% CI = 1.43-1.91) among participants reporting ≥1 day not wearing a mask compared to those who reported no days (1,592 cases, 11,717 controls). During the Delta-predominant period, the results were similar (aOR = 1.53, 95% CI = 1.23-1.89; 659 cases, 4,649 controls). This association was attenuated during the Omicron-predominant period, where odds of an infection was 16% higher (aOR = 1.16, 95% CI = 1.03-1.32; 1,563 cases, 10,960 controls).

While the effect of not wearing a mask remains significant, during the Omicron-predominant period we observed a decrease in the association between self-reported mask wearing and risk of SARS-CoV-2 infection.

Traditionally, it is believed that people's behaviours align with their attitudes; however, during COVID-19 pandemic, an attitude-behaviour gap in relation to preventive measures has been observed in recent studies. As such, the mixed-methods research was used to examine the relationships between farmers' biosecurity attitudes and behaviours in Taiwan's chicken industry based on the cognitive consistency theory.

Content analysis of face-to-face interviews with 15 commercial chicken farmers identified their biosecurity responses to infectious disease threats.

The results indicated the mismatch of farmers' attitudes and behaviours towards specific biosecurity measures, in that they act differently than they think. The findings of the qualitative research allowed the research team to conduct the subsequent quantitative, confirmatory assessment to investigate the mismatch of farmers' attitudes and behaviours in 303 commercial broiler farmers. Survey data were analyzed to discover the relationships between farmers' attitudes and behaviours in relation to 29 biosecurity measures. The results show a mixed picture. The percentage of the farmers who had the attitude-behaviour gap towards 29 biosecurity measures ranged from 13.9 to 58.7%. Additionally, at the 5% significant level, there is an association between farmers' attitudes and behaviours for 12 biosecurity measures. In contrast, a significant association does not exist for the other 17 biosecurity measures. Specifically, out of the 17 biosecurity measures, the disconnection of farmers' attitudes and behaviours was observed in three specific biosecurity measures such as using a carcass storage area.

Based on a fairly large sample of farmers in Taiwan, this study confirms the existence of an attitude-behaviour gap in context and applies social theories to provide an in-depth understanding of how infectious diseases are managed in the animal health context. As the results demonstrate the necessity of tailoring biosecurity strategies to address the gap, it is time to reconsider the current approach by understanding farmers' real attitudes and behaviours in relation to biosecurity for the success of animal disease prevention and control at the farm level.

The incidence of healthcare-associated viral respiratory infections in a pediatric hospital decreased from 1.6 /1,000 patient-days in 2019 to 0.2 /1,000 patient-days in 2020 (P < .01), and this was maintained in 2021 despite an increase in community circulation of respiratory viruses. Universal masking, stricter infection control measures, and pandemic public health interventions likely accounted for this improvement.

Hospital employees are at risk of SARS-CoV-2 infection through transmission in 3 settings: (1) the community, (2) within the hospital from patient care, and (3) within the hospital from other employees. We evaluated probable sources of infection among hospital employees based on reported exposures before infection.

A structured survey was distributed to participants to evaluate presumed COVID-19 exposures (ie, close contacts with people with known or probable COVID-19) and mask usage. Participants were stratified into high, medium, low, and unknown risk categories based on exposure characteristics and personal protective equipment.

Tertiary-care hospital in Boston, Massachusetts.

Hospital employees with a positive SARS-CoV-2 PCR test result between March 2020 and January 2021. During this period, 573 employees tested positive, of whom 187 (31.5%) participated.

We did not detect a statistically significant difference in the proportion of employees who reported any exposure (ie, close contacts at any risk level) in the community compared with any exposure in the hospital, from either patients or employees. In total, 131 participants (70.0%) reported no known high-risk exposure (ie, unmasked close contacts) in any setting. Among those who could identify a high-risk exposure, employees were more likely to have had a high-risk exposure in the community than in both hospital settings combined (odds ratio, 1.89; P = .03).

Hospital employees experienced exposure risks in both community and hospital settings. Most employees were unable to identify high-risk exposures prior to infection. When respondents identified high-risk exposures, they were more likely to have occurred in the community.

In the era of the coronavirus disease 2019 (COVID-19) pandemic, surgeons and medical staff are often at a high risk of infection in the operating room, especially when the patient is spontaneously breathing. In this study, we examined the minimum requirements for personal protective equipment with double surgical masks to potentially reduce unnecessary waste of supplies.

Two mannequins were each connected to a test lung machine simulating a surgeon and patient with spontaneous breathing. An aerosol generator containing severe acute respiratory syndrome coronavirus 2 virion particle substitutes was connected to the patient mannequin. The sampling points for the target molecules were set at different distances from the patient mannequin and sent for multiplex quantitative polymerase chain reaction analysis. Three clinical scenarios were designed, which differed in terms of the operating room pressure and whether a fabric curtain barrier was installed between the mannequins.

Analysis of the multiplex quantitative polymerase chain reaction results showed that the cycle threshold (Ct) value of the target molecule increased as the distance from the aerosol source increased. In the negative-pressure operating room, the Ct values were significantly increased at all sample points compared with the normal pressure room setting. The Ct value sampled at the surgeon mannequin wearing double face masks was significantly increased when a cloth curtain barrier was set up between the two mannequins.

Double surgical masks provide elementary surgeon protection against COVID-19 in a negative pressure operating room, with a physical barrier in place between the surgeon and patient who is spontaneously breathing during local anesthesia or sedated surgery.

The potential impact of mask-wearing specifically on early-childhood speech and language development in classrooms has not been widely reported yet, although face masks are compulsory even in educational settings during the COVID-19 pandemic. This study investigated the combined effects of face-mask usage (no mask, surgical and KF94 masks) and room acoustics (RT 0.6 s and 1.2 s, SNR 12 dB and 22 dB) on speech recognition (KS-MWL-P) in preschool children (N = 67) in realistic classroom-acoustic settings using the auralisation technique. The face mask and reverberation time affected pre-schoolers' speech recognition scores. Reducing RT in the classroom improved the pre-schoolers' speech recognition that was reduced by face masks. Children aged 4 and 5 years were affected by face masks and RT more significantly than children aged 6 years. Appropriate room acoustics for classrooms and clear speech of teachers are recommended for better speech recognition in preschool, where pre-schoolers' language and speech development usually occur.

We adopt a time series approach to investigate the historical relation between unemployment, life expectancy, and mortality rates. We fit Vector-autoregressions for the overall US population and for groups identified based on gender and race. We use our results to assess the long-run effects of the COVID-19 economic recession on mortality and life expectancy. We estimate the size of the COVID-19-related unemployment shock to be between 2 and 5 times larger than the typical unemployment shock, depending on race and gender, resulting in a significant increase in mortality rates and drop in life expectancy. We also predict that the shock will disproportionately affect African-Americans and women, over a short horizon, while the effects for white men will unfold over longer horizons. These figures translate in more than 0.8 million additional deaths over the next 15 years.

Face masks have been recommended to reduce SARS-CoV-2 transmission. However, evidence of the individual benefit of face masks remains limited, including by vaccination status.

As part of the COVID-19 Community Research Partnership cohort study, we performed a nested case-control analysis to assess the association between self-reported consistent mask use during contact with others outside the household and subsequent odds of symptomatic SARS-CoV-2 infection (COVID-19) during November 2020-October 2021. Using conditional logistic regression, we compared 359 case-participants to 3544 control-participants who were matched by date, adjusting for enrollment site, age group, sex, race/ethnicity, urban/rural county classification, and healthcare worker occupation.

COVID-19 was associated with not consistently wearing a mask (adjusted odds ratio [aOR] 1.49; 95% confidence interval [CI] [1.14, 1.95]). Compared with persons ≥14 days after mRNA vaccination who also reported always wearing a mask, COVID-19 was associated with being unvaccinated (aOR 5.94; 95% CI [3.04, 11.62]), not wearing a mask (aOR 1.62; 95% CI [1.07, 2.47]), or both unvaccinated and not wearing a mask (aOR 9.07; 95% CI [4.81, 17.09]).

Our findings indicate that consistent mask wearing can complement vaccination to reduce the risk of COVID-19.