Sero-protection of Hepatitis B vaccine and factors associated with vaccine failure among vaccinated medical students at Makerere University

Abstract

Hepatitis B virus infection is a major global health problem which is known to cause liver failure, cirrhosis and hepatocellular carcinoma. Production of HbsAb which is stimulated by HBV vaccine provides sero- protection against HBV infection. However, not all vaccinated individuals develop protective or durable levels of antibody against HbsAg due to vaccine failure. Testing for HbsAb and establishing the extent of sero-protection achieved after vaccination is important. The aim of this study therefore was to determine the sero-protection of hepatitis B vaccine among vaccinated medical students at COVAB in Makerere University and factors associated with the vaccine failure. A cross-sectional study was conducted using a random sampling technique. One hundred and fifty two medical students at COVAB in Makerere University who had received atleast one dose of the vaccine and had well documented vaccination cards were enrolled. Socio-demographic characteristics were obtained through a structured questionnaire and three to four millilitres of blood were collected from each child. Fastep rapid diagonistic test was used for qualitative detection of HbsAb and HbcAb and subsequent HBV viral DNA detection among HbcAb positive participants. The mean age was 24 +1 (SD) years. Anti-HBs were detected in 92.1% of participants with a slightly higher proportion of females 50/52(96.2%) than males 90/100(90%).The proportion of participants with a protective antibodies was significantly associated to the number of vaccine doses received. Seroprevalence of HbcAb was 11.8% .Occult hepatitis B infection was not detected in any of the HbcAb positive participants.In conclusion, there is a high rate of sero-protection conferred by hepatitis B vaccine among vaccinated medical students at COVAB in Makerere University which is associated with full vaccine dose adherence.