VIENNA — Epidemiological modelling showed that scale-up of hepatitis B mother-to-child transmission intervention and treatment in Africa will be as important in the progress to elimination as infant vaccination, according to a presentation at the International Liver Congress 2019.
“Modelling is a way to use data of different types and combine them together under strictly defined rules,” Shevanthi Nayagam, MD, from Imperial College London in the United Kingdom, said during her presentation. “It does not replace empirical data, but it is a useful tool. The questions modelling can answer are whether a goal is possible, how it can be done in a cost-effective way, and how can we monitor the progress of our interventions?”
Nayagam first addressed China as an example of an “incredible success story” in mother-to-child transmission (MTCT) HBV intervention. The country has managed to achieve high coverage of both infant and birth-dose interventions through abolishing patient fees, gaining funding support from the Global Alliance for Vaccines and Immunization, and increasing hospital births with rural reform policies.
In Africa, however, there is low coverage of MTCT interventions. Currently, only 12 countries have introduced birth dosing into national policy and the regional coverage of birth dosing is around 10%. Additionally, there is no systematic screening of pregnant mothers for HBV and the many barriers to birth dose vaccination include high rates of unassisted births.
“Successful implementation of any targeted strategy intervention requires antinatal screening with hepatitis B surface antigen, which is not routinely performed, and hepatitis e-antigen viral load testing to stratify transmission risk, which is limited by cost and availability,” Nayagam said.
Other constraints in quantifying the impact of intervention scale-up include limited data on HBV epidemiology and intervention efficacy in Africa, along with uncertainty around which models of care will lead to successful uptake of interventions in the face of costs.
Nayagam stated that there is promising progress on the road to elimination of HBV, but there remains large heterogeneity between global regions. Focus is needed on building evidence-based strategies for scaling up HBV MTCT screening and treatment interventions in Africa.
“There are a variety of roles that modeling can play to help guide public health policy both at global and country levels: we can argue the case, we can guide strategy decisions, help set targets, and monitor progress,” she said. “However, to achieve any of this, we need better empirical data to refine epidemiological projections and make this a useful tool.” – by Talitha Bennett
Nayagam S. Epidemiological models to guide targets. Presented at: International Liver Congress; April 10-14, 2019; Vienna, Austria.
Disclosures: Healio Gastroenterology and Liver Disease was unable to confirm relevant financial disclosures at the time of publication.