Unsolved problems and future perspectives of hepatitis B virus vaccination

Table 1 Prevalence and transmission of hepatitis B virus

Prevalence	High	Intermediate	Low
Carrier rate	≥ 8%	2%-7%	≤ 1%
Region	Southeast Asia	Mediterranean basin	United States
	China	Eastern Europe	Canada
	Pacific islands	Central Asia	Central Asia
	Sub-Saharan Africa	Japan	Western Europe
	Alaska (Eskimos)	Latin and South America	Australia
		Middle East	New Zealand
Predominant age at infection	Perinatal	Early childhood	Adult
	Early childhood
Predominant mode of infection	Maternal to infant	Percutaneous	Sexual contact
	Percutaneous	Sexual contact	Percutaneous

Table 2 Factors associated with poor response to hepatitis B virus vaccination

Factors
Underlying medical conditions
Chronic HBV infection
Hemodialysis
Immature neonates
HIV infection
Immunosuppressor administration
Genetic factors
HLA haplotypes
Celiac disease
SNPs (cytokine, chemokine)
Technical errors
Intra-gluteal injection
Inappropriate storage conditions

SNPs: Single nucleotide polymorphisms; HLA: Human leukocyte antigen; HBV: Hepatitis B virus.

Table 3 High risk individuals for hepatitis B virus infection and recommendations for booster vaccination

Individuals	Booster recommendation
Health-care workers	Single dose if anti-HBs < 10 mIU/mL
Men who have sex with men	Ensure primary vaccination, boosters are unnecessary
Persons with multiple sexual partners	Ensure primary vaccination, boosters are unnecessary
Injection drug users	No evidence to support booster vaccinations
Patients with hemodialysis	Additional boosters to maintain anti-HBs > 10 mIU/mL
Institutionalized patients	Not recommended
Public safety workers	Single dose if anti-HBs < 10 mIU/mL
Spouse, sexual partners and household members of HBV carriers	Receive primary vaccination, boosters are unnecessary
Recipients of liver transplantation	Additional boosters to maintain anti-HBs > 10 mIU/mL

HBs: Hepatitis B surface antigen.