Hepatitis B sero-prevalence in children under 15 years of age in South Africa using residual samples from community-based febrile rash surveillance

A case-control study of risk factors for incident hepatitis B virus infection in South African blood donors

OBJECTIVES

Hepatitis B virus (HBV) infection remains a global health problem. Risk factors for HBV infection are usually assessed in prevalent rather than incident infections. To identify demographic and behavioral risks associated with incident HBV among South African blood donors.

METHODS

A case-control study was performed between November 2014 and January 2018. Cases were blood donors testing positive for HBV DNA with or without hepatitis B surface antigen but negative for antibody to hepatitis B core antigen. Participants completed an audio computer-assisted structured interview on exposures during the previous 6 months. Sex-specific multivariable logistic regression yielded independent associations between risks and HBV infection.

RESULTS

56 females and 37 males with incident HBV were compared to 438 female and 439 male controls, respectively. For females, risk factors were accepting money or goods for sex, using agents to prepare one's anus prior to anal sex, penetrating injury, non-Black race, and lower educational status. Men reporting homosexual or bisexual orientation or sex with other men, previous injury, referral for HBV testing, or lack of medical insurance were at increased risk. For both sexes, having more than two male sexual partners increased risk.

CONCLUSIONS

Sexual behaviors predominated over parenteral exposures as risks for incident HBV in both female and male blood donors.

A systematic review reveals that African children of 15-17 years demonstrate low hepatitis B vaccine seroprotection rates

Childhood HBV immunization remains globally fundamental to the elimination of hepatitis B virus (HBV). However, monitoring proportions of HBV vaccine seroprotection and their determinants among African Pediatric recipients is crucial. This study sought to verify extent of immune protection accorded by the HBV vaccine in African children of up to 17 years of age by pooling the prevalence of seroprotection reported by primary studies conducted in the Northern, Western, and Southern African regions. We included 19 eligible articles out of the 197 initially downloaded, published from 1999 to 2021 from African Journals Online (AJOL), EMBASE, Scopus, and PubMed. The study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO), University of York Centre for Reviews and Dissemination, under the registration number CRD42022361277. Significantly higher (p < 0.0001) proportion of HBV vaccine seroprotection (69.07%) was found among children under 15 years of age than children 15-17 years (32.368%), 95% CI [34.2454-39.0847%]. Whereas successful integration of the HBV vaccine on the extended programs on immunizations (EPI) has been a major achievement in the reduction of HBV infection in Africa, markedly reduced HBV vaccine seroprotection is persistently demonstrated among adolescent children 15-17 years of age. Future studies are required to clarify the need for booster dose vaccination in most at risk populations and age groups.

Hepatitis B infection status among South Africans attending public health facilities over a five-year period: 2015 to 2019

Hepatitis B, a potentially life-threatening viral infection of the liver, remains a global public health concern despite the availability of effective vaccines for over three decades. The aim of our study was to provide national data on active hepatitis B infections in the public health sector of South Africa. We conducted retrospective analyses on national laboratory data over the period 2015 to 2019. We identified 176,530 cases who tested positive for HBsAg (active infection) with a test positivity rate of 9.02%. Of these active infections, 11,355 (6.43%) were found to be chronically infected. We linked 24,839 (14.07%) and 2,461 (21.67%) HBeAg positive results to all active HBV infections and identified chronic infections respectively. Clearance of HBsAg was observed in 5,569 cases, inclusive of clearance in 135 chronic cases. Active HBV infections were significantly higher in men than women over the five years (p < 0.0001). Among individuals who were vaccine-eligible as infants (0 to 19 years old), we observed 4,981 active HBV infections, including 1,131 infections under five years old, majority of which (65.78%) were under one year old. In the under five-year age group, the HBsAg population positivity rate was 0.02% and test positivity rate was 4.83%. Among all women with active HBV infections (78,935), 85.17% were of reproductive age and of these, 13.73% were HBeAg positive. Without a birth dose of the HBV vaccine, lack of routine HBsAg screening at antenatal care, and HBsAg and HBeAg prevalence among women of reproductive age, it is likely that the majority of cases under five years old were vertically infected. Optimal HBV vaccine coverage, inclusive of a birth dose, is key to eliminating horizontal and vertical transmission of HBV. Early identification of HBV chronicity through real time data analysis is fundamental in reducing the risk of liver cirrhosis and hepatocellular carcinoma.

Hepatitis B Virus Immunity Gap: A Six-Year Laboratory Data Review of Hepatitis B Serological Profiles in Gauteng Province, South Africa

Background

In 1995, the hepatitis B vaccine in South Africa was incorporated into the childhood expanded programme of immunization. We report on immunity gaps of laboratory-based hepatitis B virus (HBV) among patients in public facilities in Gauteng Province from 1st January 2014 to 31st December 2019. Methodology. We analyzed HBV serological data extracted from the National Health Laboratory Services Central Data Warehouse (NHLS CDW). A descriptive analysis was performed for hepatitis B surface antigen (HBsAg), antibodies to HBV core (anti-HBc) total, anti-HBc IgM, and antibodies to HBV surface antigen (anti-HBs) according to annual distribution, age groups, and sex.

Results

The HBsAg positivity rate was 7.0% (75,596/1,095,561; p=0.001): 7.4% (96,532/944,077) in the 25 years and over age group and 4.0% (358/9,268 and 325/10,864) in the under 5 and 13-24 year age groups. The positivity rates of the other HBV serological markers were as follows: anti-HBc total was 37.0% (34,377/93,711; p  <  0.001), anti-HBc IgM was 2.4% (5,661/239,237; p=0.05), and anti-HBs was 37.0% (76,302/206,138; p ≤ 0.001). Naturally acquired HBV immunity was detected in 25.7% (11,188/43,536) of patients in the 25 years and over age group, and 9.7% and 8.2% (113/1,158 and 541/6,522) among those under 5 years and 13-24 year age group, respectively (p  <  0.001). Vaccine-induced immunity was 56.6% (656/1,158) in children under 5 years and 10.2% (4,425/43,536) among those 25 years and above (p  <  0.001). Fifty-six percent (29,404/52,581) of patients were HBV seronegative; predominantly among patients in the 13-24 year age group (60.6%; (3,952/6,522)) and 25 years and over (56.3% (24,524/43,536)) (p=<0.001).

Conclusion

The HBV infection seroprevalence remains high in South Africa, with Gauteng province having high intermediate endemicity. However, the HBV immunity gap has shifted from younger children to older children and adults.

Low prevalence of hepatitis B virus infection in HIV-uninfected pregnant women in Cape Town, South Africa: implications for oral pre-exposure prophylaxis roll out

Background

Oral daily preexposure prophylaxis (PrEP) using emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF) is recommended as standard of care for prevention in individuals at high risk for HIV infection, including pregnant and postpartum cisgender women. FTC/TDF is also active against hepatitis B virus (HBV); however, concern has been raised that providing PrEP to individuals infected with HBV could lead to hepatitis flares and liver injury, especially in the setting of suboptimal PrEP use.

Methods

We conducted a cross-sectional analysis of baseline data from the PrEP in pregnant and postpartum women (PrEP-PP) cohort study from February 2020–March 2022 in one antenatal care clinic in Cape Town, South Africa (SA) to evaluate: (1) the field performance of a point of care test (POCT) (Determine II, Abbott Inc., Japan) for diagnosis of hepatitis B surface antigen (HBsAg) in a maternity setting, (2) the prevalence of HBV in a cohort of pregnant women not living with HIV.

Results

We enrolled 1194 HIV sero-negative pregnant women at their first antenatal visit. Median age was 26 years (IQR = 22–31 years); 52% were born before 1995 (before universal HBV vaccination had started in South Africa). Median gestational age was 22 weeks (IQR = 16–30 weeks). There were 8 POCT and laboratory confirmed HBV cases among 1194 women. The overall prevalence of 0.67% (95% CI = 0.34–1.32%). In women born before 1995, 8 of 622 women were diagnosed with HBsAg; the prevalence was 1.29% (95% CI = 0.65–2.52%), and in women born in 1995 or after (n = 572); the prevalence was 0% (95% CI = 0.0–0.67%). We confirmed the test results in 99.8% of the rapid HBsAg (Determine II). Sensitivity was 100% (95% CI = 68–100%). Specificity was 100% (95% CI = 99.67–100%).

Conclusion

The prevalence of HBV was very low in pregnant women not living with HIV and was only in women born before the HBV vaccine was included in the Expanded Program of Immunization. The Determine II POCT HBsAg showed excellent performance against the laboratory assay. HBV screening should not be a barrier to starting PrEP in the context of high HIV risk communities.

Prevalence and Risk Factors for Hepatic Steatosis in Children With Perinatal HIV on Early Antiretroviral Therapy Compared to HIV-Exposed Uninfected and HIV-Unexposed Children

Objectives

We evaluated the prevalence and risk factors for hepatic steatosis in South African children with perinatally acquired HIV (PHIV) who started treatment early and remain on long-term antiretroviral therapy (ART) compared to HIV-uninfected children.

Design

A cross-sectional study from April 2019 to October 2021. PHIV, HIV-exposed uninfected (HEU) and HIV-unexposed (HU) children were enrolled from an ongoing cohort study.

Methods

All children had transient elastography (TE) with controlled attenuation parameter (CAP). Liver enzymes, lipogram, insulin and glucose were sent after an overnight fast. Multivariable linear regression analyses identified predictors of CAP. Hepatic steatosis was defined as CAP>248kPa.

Results

215 children (111 [52%] male; median age 14.1 years; IQR 12.7-14.9) participated in the study, 110 PHIV, 105 HIV-uninfected (36 HEU, 69 HU). PHIV initiated ART at a median age of 2.7 months (IQR 1.8-8.5). Hepatic steatosis prevalence was 9% in PHIV, 3% in HEU and 1% in HU children (p = 0.08). However, 8% of lean (body mass index z-score ≤ +1) PHIV had hepatic steatosis compared to zero lean HEU or HU children (p = 0.03). In multivariable linear regression analysis of all PHIV, body mass index (BMI) z-score was positively associated with CAP (p = 0.001) while CD4 count (p = 0.02) and duration of suppression of HIV viraemia (p = 0.009) were negatively associated with CAP, adjusting for age, sex and ethnicity.

Conclusions

Hepatic steatosis prevalence was higher in lean PHIV than lean HIV-uninfected South African children. Longer suppression of HIV viraemia and higher CD4 count were associated with lower CAP and might be protective factors for hepatic steatosis in PHIV children.

Prevalence and incidence rates of laboratory-confirmed hepatitis B infection in South Africa, 2015 to 2019

Background

Hepatitis B virus (HBV), a global public health threat, is targeted for elimination by 2030. As national HBV prevalence and incidence is lacking for South Africa, our study aimed to provide such data in the public health sector.

Methods

We analysed laboratory-confirmed HBV data from 2015 to 2019 to determine annual prevalence and incidence rates of HBV infection per 100,000 population, HBsAg and anti-HBc IgM test positivity rates, and HBsAg and anti-HBc IgM testing rates per 100,000 population. Time trend and statistical analyses were performed on HBsAg and anti-HBc IgM test positivity rates.

Results

The national prevalence rate of HBV infection per 100,000 population increased from 56.14 in 2015 to 67.76 in 2019. Over the five years, the prevalence rate was higher in males than females, highest amongst individuals 25 to 49 years old and highest in Gauteng province. The HBsAg test positivity rate dropped from 9.77% in 2015 to 8.09% in 2019. Over the five years, the HBsAg test positivity rate was higher in males than females, amongst individuals 25 to 49 years old and amongst individuals of Limpopo province. Amongst HBsAg positive children under 5 years old, the majority (65.7%) were less than a year old. HBsAg testing rates per 100,000 population were higher in females under 45 years of age and in males 45 years and above. The national incidence rate of acute HBV infection per 100,000 population dropped from 3.17 in 2015 to 1.69 in 2019. Over the five-year period, incidence rates were similar between males and females, highest amongst individuals 20 to 39 years old and highest in Mpumalanga province. Amongst individuals 20 to 24 years old, there was a substantial decline in the incidence and anti-HBc IgM test positivity rates over time. Anti-HBc IgM testing rates per 100,000 population were higher in females under 40 years of age and in males 40 years and above.

Conclusion

Critical to hepatitis B elimination is strengthened infant vaccination coverage and interruption of vertical transmission. Transmission of HBV infection in adults may be reduced through heightened awareness of transmission routes and prevention measures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12391-3.

Prevalence of viral hepatitis B and C in Sierra Leone-current knowledge and knowledge gaps: a narrative review

There are no comprehensive data on viral hepatitis from Sierra Leone; however, a huge disease burden has been observed in different subpopulations. This review summarizes available data on hepatitis B and C virus (HBV and HCV) prevalence in Sierra Leone and identifies knowledge gaps. Despite the non-uniformity of the studies and the lack of systematic case recording, different reports published in recent decades yielded a hepatitis B prevalence of 8.7% among healthcare workers, 11.3% among pregnant women, 15.2% among blood donors and 16.7% in school-age children. The actual HBV prevalence in the general population was reported as 21.7%; similar to what was reported for people living with human immunodeficiency virus (PLHIV). HCV prevalence is 8% and 7% in male and female blood donors, respectively, 4.1% in PLHIV and 2.0% in school children. There are significant knowledge gaps regarding the prevalence of viral hepatitis B and C in Sierra Leone, despite the high burden reported in a few studies. There are limited programmatic interventions on the control and prevention of viral hepatitis in the country. Therefore, well-structured representative studies should provide a solid understanding of the true prevalence of hepatitis B and C to inform best possible public health measures in Sierra Leone.

Hepatitis B virus infection and hepatocellular carcinoma in sub-Saharan Africa: Implications for elimination of viral hepatitis by 2030?

Elimination of viral hepatitis in sub-Saharan Africa by 2030 is an ambitious feat. However, as stated by the World Health Organization, there are unprecedented opportunities to act and make significant contributions to the elimination target. With 60 million people chronically infected with hepatitis B virus (HBV) of whom 38800 are at risk of developing highly fatal hepatocellular carcinoma (HCC) every year, sub-Saharan Africa faces one of the greatest battles towards elimination of viral hepatitis. There is a need to examine progress in controlling the disproportionate burden of HBV-associated HCC in sub-Saharan Africa within the context of this elimination target. By scaling-up coverage of hepatitis B birth dose and early childhood vaccination, we can significantly reduce new cases of HCC by as much as 50% within the next three to five decades. Given the substantial reservoir of chronic HBV carriers however, projections show that HCC incidence and mortality rates in sub-Saharan Africa will double by 2040. This warrants urgent public health attention. The trends in the burden of HCC over the next two decades, will be determined to a large extent by progress in achieving early diagnosis and appropriate linkage to care for high-risk chronic HBV infected persons.

An assessment of hepatitis B virus prevalence in South African young blood donors born after the implementation of the infant hepatitis B virus immunization program: Implications for transfusion safety

BACKGROUND

The prevalence of hepatitis B surface antigen is estimated to be 6.7% in the South African population and in April 1995 the nation introduced universal hepatitis B virus (HBV) vaccination for newborns and infants. We studied the temporal association of this program with HBV prevalence in young blood donors and the contemporary HBV incidence and residual risk of transfusion-transmitted HBV infection (TT-HBV).

METHODS

We used blood donation data from January 2011 to December 2019. Estimation of HBV prevalence donations made by first-time blood donors were analyzed by birth cohort and covariates. To estimate the incidence and residual risk of TT-HBV, mathematical models used data from both first time and repeat donors.

RESULTS

HBV prevalence in first-time donors decreased from 0.84% (95% confidence interval [CI] 0.78-0.90) in 2011 to 0.66% (95% CI 0.61-0.70) in 2019. The post-1995 birth cohort had a significantly lower HBV prevalence of 0.14% (95% CI 0.13-0.15) than the pre-1985 birth cohort of 1.29% (95% CI 1.25-1.33) and the odds of HBV infection were reduced in a multivariable model (odds ratio [OR] = 0.28, 95% CI 0.24-0.34). The residual risk of TT-HBV occurring from window-period, occult, and possible vaccine breakthrough infections were estimated at 36.9, 5.8, and 2.2 per million red blood cell transfusions, respectively.

CONCLUSION

Donors born after the start of routine HBV immunization had significantly lower prevalence of HBV infection, supporting the effectiveness of the vaccination program. The contemporary residual risk of TT-HBV has decreased and should decline further as more vaccinated young people join the donor pool.