MATERIALS AND METHODS: A prospective, cross-sectional study involving 352 students, comprising 109 (31.0%) males and 243 (69.0%) females. Blood specimens were tested for anti-HBs, where levels of ≥10 mIU/mL was considered reactive and protective. Students with non-reactive levels were given a 20 μg HBV vaccine booster. Anti-HBs levels were tested six weeks after the first booster dose. Those with anti-HBs <10 mIU/mL were then given another two booster doses, at least one month apart. Anti-HBs levels were tested six weeks after the third dose.
RESULTS: Ninety-seven students (27.6%) had anti-HBs ranging from 10 to >1000 mIU/mL while 255 (72.4%) had anti-HBs <10 mIU/mL. After one booster dose, 208 (59.1%) mounted anti-HBs ≥10 mIU/mL. Among the remaining 47 (13.3%), all except two students (0.6%) responded following completion of three vaccination doses. They were negative for HBsAg and anti-HBcore antibody, thus regarded as non-responders.
CONCLUSIONS: Anti-HBs levels waned after 20 years post-vaccination, where more than 70% were within non-reactive levels. For healthcare workers, a booster dose followed by documenting anti-HBs levels of ≥10 mIU/mL may be recommended, to guide the management of post-exposure prophylaxis. Pre-booster anti-HBs testing may not be indicated. Serological surveillance is important in long-term assessment of HBV vaccination programs. No HBV carrier was detected.
OBJECTIVE: This study aimed to detect occult hepatitis B virus in hepatitis B surface antigen-negative serum using anti-HBc as a marker of previous infection.
PATIENT AND METHODS: A total of 1000 randomly selected hepatitis B surface antigen-negative sera from blood donors were tested for hepatitis B core antibody and hepatitis B surface antibody using an ELISA and nested polymerase chain reaction was done using primers specific to the surface gene (S-gene).
RESULTS: Of the 1000 samples 55 (5.5%) were found to be reactive, of which 87.3% (48/55) were positive for hepatitis B surface antibody, indicating immunity as a result of previous infection however, that does not exclude active infection with escaped mutant HBV. Nested PCR results showed the presence of hepatitis B viral DNA in all the 55 samples that were positive for core protein, which is in agreement with the hepatitis B surface antibody result.
CONCLUSION: This study reveals the 5.5% prevalence of occult hepatitis B among Malaysian blood donors as well as the reliability of using hepatitis B core antibody in screening for occult hepatitis B infection in low endemic, low socioeconomic settings.
DESIGN AND SETTINGS: A prospective cohort study of vaccinated undergraduate students of University Putra Malaysia.
PATIENTS AND METHODS: A total of 408 undergraduate students who received infant hepatitis B vaccination volunteered for this study; 5 mL of venous blood was taken from the volunteers. Hepatitis B surface antigen (HBsAg) and core antibodies were tested using a commercially available enzyme-linked immunosorbent assay kit according to the manufacturer's instructions (DRG international Inc., USA). Molecular detection of hepatitis B viral DNA was performed using nested polymerase chain reaction.
RESULTS: The prevalence of isolated anti-HBc among the vaccinated cohort was found to be 5.0%, out of which 80% had a hepatitis B surface antibodies (anti-HBs) titer higher than 10 IU/L, while 20% had less than 10 IU/L anti-HBs titer. All the anti-HBc positivesubjects had detectable hepatitis B viral DNA in their serum. Anamnestic response was found to be 100% among isolated anti-HBc with negative antibody.
CONCLUSION: Isolated anti-HBc developed protective levels of anti-HBs after a single dose of recombinant hepatitis B vaccination. HBV DNA was detected in all isolated anti-HBc indicating occult chronic HBV infection with undetectable HBsAg.
METHODS: A multisite cross-sectional study was conducted in HIV-infected patients currently <25 years old receiving antiretroviral treatment (ART) who had HBV surface antigen (HBsAg), or HBV surface antibody (anti-HBs) or HBV core antibody (anti-HBc) tested during 2012-2013. HBV coinfection was defined as having either a positive HBsAg test or being anti-HBc positive and anti-HBs negative, reflective of past HBV infection. HBV seroprotection was defined as having a positive anti-HBs test.
RESULTS: A total of 3380 patients from 6 countries (Vietnam, Thailand, Cambodia, Malaysia, Indonesia and India) were included. The current median (interquartile range) age was 11.2 (7.8-15.1) years. Of the 2755 patients (81.5%) with HBsAg testing, 130 (4.7%) were positive. Of 1558 (46%) with anti-HBc testing, 77 (4.9%) were positive. Thirteen of 1037 patients with all 3 tests were anti-HBc positive and HBsAg and anti-HBs negative. One child was positive for anti-HBc and negative for anti-HBs but did not have HBsAg tested. The prevalence of HBV coinfection was 144/2759 (5.2%) (95% confidence interval: 4.4-6.1). Of 1093 patients (32%) with anti-HBs testing, 257 (23.5%; confidence interval: 21.0-26.0) had positive tests representing HBV seroprotection.
CONCLUSIONS: The estimated prevalence of HBV coinfection in this cohort of Asian HIV-infected children and adolescents on ART was 5.2%. The majority of children and adolescents tested in this cohort (76.5%) did not have protective HBV antibody. The finding supports HBV screening of HIV-infected children and adolescents to guide revaccination, the use of ART with anti-HBV activity and future monitoring.