The hepatitis B vaccine has been part of the South African Expanded Program on Immunization since April 1995 but its long-term impact remains unknown. This study tested 1,206 sera collected from patients aged 1-25 years from various health facilities across the country for HBV serological markers and HBV DNA. Based on the year the vaccine was introduced, samples were stratified by age into pre- and post-vaccine introduction populations, which were then compared for evidence of immunity and chronic carriage using the Chi-square test. Where HIV status was known, subset analyses were performed. Immunity to HBV infection increased from 13.0% in the pre- to 57.0% in the post-vaccine introduction population (P < 0.001). This decreased with increasing age within the post-vaccine introduction population (76.1% for 1-5 years, 50.0% for 6-10 years, and 46.3% for 11-16 years). In addition, HBV chronic carriage was significantly (P = 0.003) reduced in the post- (1.4%) compared to the pre-vaccine introduction population (4.2%). The difference in prevalence of active HBV infection in the serologically exposed pre- and post-vaccine introduction populations was not statistically significant. Subset analyses showed that evidence of immunity was significantly (P < 0.001) higher in the HIV negative compared to the HIV positive subset in both populations. Universal hepatitis B vaccination has been a remarkable success, with a significant increase in immunity to HBV infection. The observation that HBV chronic carriage increases as immunity wanes over time calls into question whether the time has come to consider a pre-adolescence vaccine booster dose policy.
Background and objective The aim of this study was to investigate the prevalence of occult hepatitis B virus (HBV) infection and the HBV surface (S) gene variants circulating in the South African population after nearly two decades of universal hepatitis B vaccination. Study design From a previous serosurvey, 201 serum samples with serological evidence of exposure to HBV were identified and these were stratified into post- and pre-vaccine introduction populations. For all samples, HBV DNA was screened and quantified using a real-time PCR assay and results analysed together with HBV serological markers. Where HIV results were available, subset analysis was performed. The HBV S gene was PCR-amplified and sequences analysed for a total of 37 isolates. Results The prevalence of occult HBV infection reduced from 70.4% in the pre-vaccine introduction era to 66.0% post-vaccine introduction. There was an association between HIV infection and an increase in prevalence of occult HBV infection within the post-vaccine introduction population, although this was not statistically significant. Furthermore, sequence analysis revealed the following HBV subgenotypes; A1 (n = 34), A2 (n = 2) and a rare D4 isolate. HBV S gene variants, including diagnostic escape mutants were isolated. Conclusion There was a decline in the prevalence of occult HBV infection in post-vaccination South Africa, although the disease burden remains significant in the HIV co-infected population. After nearly two decades of a universal hepatitis B vaccination programme, no positive selection of vaccine escape mutants were observed.
This study aimed to determine the feasibility of vaginal/cervical nurse-assisted self-sampling (NASS) and the agreement between human papilloma virus (HPV) tests on self-samples versus clinician-taken (CT) specimens.Women participated voluntarily for cervical cancer screening at St. Aklesia Memorial Hospital. Eighty-three women provided a total of 166 coupled self-taken and CT specimens collected. Specimens were stored at room temperature for a maximum of 10 months and analyzed using validated the RIATOL qPCR HPV genotyping test, a quantitative polymerase chain reaction (qPCR) high-throughput HPV E6, E7 assay. The average age of the participating women was 32 years. Seventy-three women (87.9%) felt that NASS was easy to use. An overall HPV, high-risk (HR) HPV, and low-risk HPV prevalence was 22.7% (15/66), 18.2% (12/66), and 6.1% (4/66), respectively. The overall HR HPV prevalence was 17.2% (NASS) and 15.5% (CT). The most prevalent HPV type was HPV51; HPV 16 was only detected in 1 woman (CT+NASS) and HPV18 only in 1 woman (CT). The overall measurement agreement between self-taken and CT samples was moderate with a kappa value of 0.576 (P < .001). Lifetime partnered with >2 men were associated with HR HPV positivity (P < .001). There was a strong statistical association between HR HPV positivity and visual inspection with acetic acid- positive (P < .001). The NASS for HPV testing could be seen as an alternative option and might be acceptable to Ethiopian women. The overall HR HPV prevalence was comparable with Sub-Saharan countries in the general population.
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