Prevalence and factors associated with seroprotection after primary series of hepatitis b vaccination among children seen in the outpatient setting of Philippine Children’s Medical Center

ABSTRACT

BACKGROUND@#Hepatitis B is a vaccine-preventable condition that could develop into cirrhosis and hepatocellular carcinoma. Identifying patients at risk for Hepatitis B infection despite the universal implementation of Hepatitis B vaccination will help improve the immunization program.@*OBJECTIVE@#To determine the prevalence and factors associated with seroprotection among children 3 months to 18 years old primary Hepatitis B vaccination series.@*METHODOLOGY@#This is a cross-sectional study among children 3 months to 18years old with complete Hepatitis B immunization. Demographic, social and clinical data were correlated with response to HBsAg, Anti-HBs and Total Anti-HBc tests.@*RESULTS@#Among 110 subjects from different age groups, 52% had seroprotective anti-HBs levels (>10 mIU/ml). Seventy four percent seroprotection was seen in subjects with <5 years interval from vaccination, 26% in cases after 5-10 years, and 38% at 10 years after vaccination with significant difference. Other factors such as gender, geographic area, type of vaccine, schedule, age at first dose and place of vaccine were not associated with seroprotection.@*CONCLUSION@#Fifty two percent seroprotection from Hepatitis B infection among different age groups was demonstrated in our study. Interval year after vaccination was the only factor established to have significant association with seroprotection, with < 50% decline of anti-HBs level at 5 years or more after vaccination. @*RECOMMENDATIONS@#Community studies with larger population are needed. Anti-HBs detection 5 years or more post-vaccination may be considered to identify patients at risk for breakthrough infection. Repeat serologic testing among non-seroprotected subjects is recommended.