The spread of hepatitis B virus (HBV) presents a challenge to global health and is a major contributor to infant mortality. Furthermore, infant infection, which is driven by mother-to-child transmission, frequently leads to chronic HBV infection. To curtail the disease burden caused by HBV infection, the World Health Organization (WHO) revised its recommendations for HBV prevention in 2020 to include peripartum antiviral prophylaxis (PAP) among women exhibiting a high viral load of HBV. In the May 2023 publication in The Lancet Gastroenterology and Hepatology, Dr Shevanthi Nayagam and colleagues utilised epidemiological modelling to compare the potential cases of chronic HBV averted under varying vaccination policies for HBV-positive pregnant women and neonatal vaccination. The authors projected that integrating the new guidelines into HBV infection management would lead to a net decrease of 1.1 million in neonatal infections at an attainable cost in 28 of the 106 countries considered. In the 16 major markets (16MM: US, France, Germany, Italy, Spain, UK, Japan, Australia, Brazil, Canada, China, India, Mexico, Russia, South Africa, and South Korea), GlobalData epidemiologists forecast an increase in diagnosed prevalent cases of chronic hepatitis B from nearly 21,816,000 in 2023 to over 22,430,000 in 2029, a trend which may diminish following the successful implementation of new WHO vaccination guidelines.
Dr Nayagam and colleagues analysed the impact of WHO’s HBV vaccination guidance using a dynamic simulation model of the HBV epidemic in 110 countries. The model was run under four different interventions: neonatal vaccination, PAP for pregnant women exhibiting high viral load, PAP-universal for all HBV-positive pregnant women, and vaccination for pregnant women screened positive for HBV based on HBeAg and HbsAg antigen tests. Simulations indicated that among these interventions, neonatal vaccination produced the most effective results, potentially averting six million cases worldwide between 2024 and 2030. Furthermore, the implementation of the new WHO guidance would bolster these numbers, averting another 1.1 million cases. If applied in tandem, the two interventions are projected to reduce incident cases of chronic HBV infections by 90% across all WHO regions. However, analysis also showed that this approach would only meet maximum cost-effectiveness in 28 countries, largely due to the additional costs incurred by the diagnostic screening needed for antigen viral load-based vaccination strategies. Accordingly, the authors suggest that in countries for which the WHO guidance is not financially feasible, most of which are concentrated in Africa and Asia, universal maternal vaccination could allow for significant reductions in chronic HBV infection incidence at a feasible cost point.
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The analysis performed by Nayagam and colleagues presents an optimistic case for the widespread implementation of the WHO’s 2020 HBV prophylaxis recommendations. While the inherently variable nature of health policy across different countries complicates the WHO target of a 90% reduction in incident cases of chronic HBV infection, the study’s model may bolster a case for financial and logistic support for countries otherwise unable to independently enact PAP among high viral load pregnant women and newborns. Successful implementation of the PAP among high viral load HBV patients or neonatal vaccination may lead to a reduction in the caseloads originally forecasted.
