Proportion of pregnant women with HBV infection eligible for antiviral prophylaxis to prevent vertical transmission: A systematic review and meta-analysis

Background & Aims: In 2020, the World Health Organization (WHO) recommended peripartum antiviral prophylaxis (PAP) for pregnant women infected with hepatitis B virus (HBV) with high viremia (>= 200,000 IU/ml). Hepatitis B e antigen (HBeAg) was also recommended as an alternative when HBV DNA is unavailable. To inform policymaking and guide the implementation of prevention of mother-to-child transmission strategies, we conducted a systematic review and meta-analysis to estimate the proportion of HBV-infected pregnant women eligible for PAP at global and regional levels. Methods: We searched PubMed, EMBASE, Scopus, and CENTRAL for studies involving HBV-infected pregnant women. We extracted proportions of women with high viremia (>= 200,000 IU/ml), proportions of women with positive HBeAg, proportions of women cross-stratified based on HBV DNA and HBeAg, and the risk of child infection in these maternal groups. Proportions were pooled using random-effects meta-analysis. Results: Of 6,999 articles, 131 studies involving 71,712 HBV-infected pregnant women were included. The number of studies per WHO region was 66 (Western Pacific), 21 (Europe), 17 (Africa), 11 (Americas), nine (Eastern Mediterranean), and seven (South-East Asia). The overall pooled proportion of high viremia was 21.27% (95% CI 17.77-25.26%), with significant regional variation: Western Pacific (31.56%), Americas (23.06%), Southeast Asia (15.62%), Africa (12.45%), Europe (9.98%), and Eastern Mediterranean (7.81%). HBeAg positivity showed similar regional variation. After cross-stratification, the proportions of high viremia and positive HBeAg, high viremia and negative HBeAg, low viremia and positive HBeAg, and low viremia and negative HBeAg were 15.24% (95% CI 11.12-20.53%), 2.70% (95% CI 1.88-3.86%), 3.69% (95% CI 2.86-4.75%), and 75.59% (95% CI 69.15-81.05%), respectively. The corresponding risks of child infection following birth dose vaccination without immune globulin and PAP were 14.86% (95% CI 8.43-24.88%), 6.94% (95% CI 2.92-15.62%), 7.14% (95% CI 1.00-37.03%), and 0.14% (95% CI 0.02-1.00%). Conclusions: Approximately 20% of HBV-infected pregnant women are eligible for PAP. Given significant regional variations, each country should tailor strategies for HBsAg screening, risk stratification, and PAP in routine antenatal care. Impact and implications: In 2020, the WHO recommended that pregnant women who test positive for the hepatitis B surface antigen (HBsAg) undergo HBV DNA testing or HBeAg and those with high viremia (>= 200,000 IU/ml) or positive HBeAg receive PAP. To effectively implement new HBV PMTCT interventions and integrate HBV screening, risk stratification, and antiviral prophylaxis into routine antenatal care services, estimating the proportion of HBV-infected pregnant women eligible for PAP is critical. In this systematic review and meta-analysis, we found that approximately one-fifth of HBV-infected pregnant women are eligible for PAP based on HBV DNA testing, and a similar proportion is eligible based on HBeAg testing. Owing to substantial regional variations in eligibility proportions and the availability and costs of different tests, it is vital for each country to optimize strategies that integrate HBV screening, risk stratification, and PAP into routine antenatal care services. Systematic review registration: This study was registered with PROSPERO (Protocol No: CRD42021266545).