INTRODUCTION
Vaccines are immunizing agents for the prevention of infectious diseases caused by pathogenic microorganisms and their metabolites, which are artificially attenuated, inactivated or genetically modified. Vaccines not only provide individual protection to those vaccinated, but also produce herd immunity by reducing the disease's spread among the population when reaching a certain percentage of the immunized population, thereby protecting those who are unable to be vaccinated for certain reasons[1]. Additionally, vaccines possess economic benefits, with deaths and disabilities prevented by vaccination leading to the increased economic productivity in addition to the reduced healthcare expenditures[2]. It has also been demonstrated that vaccination can slow down the rise of antimicrobial drug resistance and address global health threats by directly reducing the incidence of susceptible and drug-resistant infections or decreasing the overall incidence of disease, thereby reducing the appropriate and inappropriate use of antimicrobials[3].
Infectious diseases are one of the leading causes of death in children due to their underdeveloped immune system as susceptible to numerous infectious diseases[4]. Early-life infections may potentially result in unfavorable growth and developmental delays, exerting negative influences on long-term health and cognitive abilities[5]. In order to protect children from serious and even fatal infectious diseases, the World Health Organization (WHO) launched the Expanded Programme on Immunization in May 1974. Thereafter, vaccination lists and schedules have been established to promote child vaccine coverage and broaden the scope of vaccination.
Currently, almost all countries have routine immunization schedules in place to ensure routine childhood vaccination coverage. Routine pediatric vaccination has significantly reduced morbidity, disability, and mortality from vaccine-preventable diseases[6]. The WHO globally estimated that vaccines may prevent 2-3 million deaths annually. Moreover, due to the usage of vaccines, a wide range of infectious diseases that have caused severe health and life-threatening damage to children throughout history have been largely controlled; for instance, smallpox has been eradicated from the world, in which several regions such as the Americas, the Western Pacific, and Europe have been certified as polio-free, and the prevalence of infectious diseases (e.g., measles and mumps) has been remarkably reduced[7].
However, routine pediatric vaccination coverage is affected by several factors. A recent review published in World Journal of Virology by Locke et al[8] studied and examined the influences of coronavirus disease 2019 (COVID-19) on infant, child, and adolescent vaccinations. This review revealed a decline, delays, or interruptions in the routine pediatric vaccination during the pandemic, with a reduction in some countries’ pre- and post-COVID-19 pandemic eras, and emphasized the importance of governmental efforts in the maintenance and reduced delays in routine childhood vaccinations. Beyond variations in vaccination coverage attributed to differences in country, region, ethnicity, or economic status, contemporary attitudes toward vaccines play a pivotal role in influencing vaccination coverage. Diseases that were once feared and inspired a desire for vaccination are now remarkably less prevalent, and some publics are skeptical about vaccinations due to concerns arising from side effects of vaccinations[1]. In addition, regional or worldwide outbreaks may cause a reduction or interruption in vaccination coverage, including regional conflicts and pandemics[9-11]. The COVID-19 outbreak that started in December 2019 globally caused disruptions or reductions in vaccination coverage, in which routine pediatric vaccination coverage was also severely affected. In the present study, the influences of the COVID-19 pandemic on the routine pediatric vaccination and the corresponding coping and preventative strategies were discussed.
METHODOLOGY
The MEDLINE and PubMed databases were search to retrieve articles that were published in English using associations of search queries related to the concepts of COVID-19 (severe acute respiratory syndrome coronavirus 2), pandemic (epidemic, outbreak), pediatric (childhood), and vaccination (vaccine). Further references were added by hand-searching in the relevant literature, and they were included in the final manuscript based on consensus among all authors.
ROUTINE PEDIATRIC VACCINATION DURING THE COVID-19 PANDEMIC
Locke et al[8] retrospectively analyzed changes in routine childhood vaccination coverage during the COVID-19 pandemic and its epidemiological factors, and they found that routine vaccination coverage was severely affected by COVID-19, especially among children in the United States. Routine childhood vaccines, such as diphtheria-tetanus-pertussis (DTP) vaccine, measles, mumps and rubella (MMR) vaccine, and polio vaccine exhibited a decrease in vaccination coverage, with DTP and MMR vaccines showing a reduction of more than 7.0% in vaccination coverage compared with expectations. Kujawski et al[12] assessed the influences of the COVID-19 pandemic on pediatric and adolescent vaccination administration in the United States, and also revealed substantial disruptions in vaccination administration for children and adolescents during the COVID-19 pandemic in 2020 and early 2021. Other studies reported that childhood vaccination rates significantly decreased in some regions and countries, such as Alabama[13], Singapore[14], and Brazil[15] during the COVID-19 pandemic. Carias et al[16] projected measles vaccination coverage for the cohort of children, and found that projected vaccination coverage would drop to 80% or below after stay-at-home orders were lifted during the pandemic. Therefore, sustained catch-up immunization efforts were needed.
The COVID-19 pandemic affected immunization programs worldwide, and it led to millions of children missing out on vaccinations, contributing to a substantial rise in the count of zero-dose and incompletely vaccinated children[17]. From the commencement of the COVID-19 epidemic until 2021, there was a general decrease in global childhood vaccination rates[18]. Childhood vaccination rates had recovered in 2022, while still had not returned to pre-epidemic rates, and the recovery level was uneven across countries[19]. In addition to the adverse effects of social determinants of health such as unemployment, poverty, and disruption of education[20], the lack of vaccine supply due to shortage of health resources and health manpower contributed to the decline in vaccination coverage during the epidemic[21]. Moreover, skepticism about the safety, efficacy, and necessity of vaccines, as well as concerns about their side effects, contributed to the decline in vaccination coverage, with the extent and magnitude of the problem increasing further during the epidemic[20]. Another study demonstrated that vaccination confidence is lost mainly among young people, which is a worrying trend that may have long-term public health consequences[22]. Furthermore, Kraaijeveld et al[23] pointed out that healthy children’s routine vaccination against COVID-19 was ethically unjustified.
COPING AND PREVENTATIVE STRATEGIES
Interruptions in vaccination have a negative impact on children's health, and studies found that interruptions in routine vaccination could increase the risk of mortality from vaccine-preventable diseases by 10.0%. Moreover, race, age, and place of residence are all factors that influence vaccine interruptions and routine vaccination coverage. The authors recommend that governments take proactive measures to address missed vaccinations by prioritizing catch-up programs. Moreover, communities should establish a more inclusive system ensuring universal access to vaccines for all children[8]. Some countries and the United Nations had also taken steps to restore and compensate for interruptions in routine vaccination coverage[24]. The WHO, together with the United Nations Children's Fund and the Global Alliance for Vaccines and Immunization, and other organizations, have called 2023 a year of intensified action to "catch up", calling for child immunization services to be restored to pre-pandemic levels[19]. Shet et al[21] proposed several actions to help restore vaccination, including identifying and implementing catch-up vaccination strategies, strengthening vaccine routine information management systems, adapting health planning and establishing best practices to more effectively respond to the future epidemics.
CONCLUSION
Vaccination is an important measure to protect the population from infections and detrimental influences of vaccine-preventable diseases. Increasing vaccination coverage not only reduces the incidence of several diseases and their serious consequences and improves the humans’ health, but also plays a pivotal role in the economy and in addressing global health threats. A decline in vaccination coverage for various reasons may negatively affect children's health and even threaten their future lives. Therefore, innovative actions and strategies should be taken to restore the stagnation or even decline in routine pediatric vaccination coverage during the COVID-19 pandemic and minimize their public health effects in the future.
ACKNOWLEDGEMENTS
We express our gratitude to all colleagues, reviewers, and editors for their valuable contributions in enhancing the quality of this manuscript.
Provenance and peer review: Invited article; Externally peer reviewed.
Peer-review model: Single blind
Specialty type: Health policy and services
Country/Territory of origin: China
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P-Reviewer: Setiawati Y, Indonesia S-Editor: Liu JH L-Editor: A P-Editor: Bu BZ
