A retrospective study assessing the clinical outcomes and costs of acute hepatitis A in Cape Town, South Africa

Modelling the Cost-Effectiveness of Hepatitis A in South Africa

The World Health Organization (WHO) recommends the consideration of introducing routine hepatitis A vaccination into national immunization schedules for children ≥ 1 years old in countries with intermediate HAV endemicity. Recent data suggest that South Africa is transitioning from high to intermediate HAV endemicity, thus it is important to consider the impact and cost of potential routine hepatitis A vaccination strategies in the country. An age-structured compartmental model of hepatitis A transmission was calibrated with available data from South Africa, incorporating direct costs of hepatitis A treatment and vaccination. We used the calibrated model to evaluate the impact and costs of several childhood hepatitis A vaccination scenarios from 2023 to 2030. We assessed how each scenario impacted the burden of hepatitis A (symptomatic hepatitis A cases and mortality) as well as calculated the incremental cost per DALY averted as compared to the South African cost-effectiveness threshold. All costs and outcomes were discounted at 5%. For the modelled scenarios, the median estimated cost of the different vaccination strategies ranged from USD 1.71 billion to USD 2.85 billion over the period of 2023 to 2030, with the cost increasing for each successive scenario and approximately 39-52% of costs being due to vaccination. Scenario 1, which represented the administration of one dose of the hepatitis A vaccine in children < 2 years old, requires approximately 5.3 million vaccine doses over 2023-2030 and is projected to avert a total of 136,042 symptomatic cases [IQR: 88,842-221,483] and 31,106 [IQR: 22,975-36,742] deaths due to hepatitis A over the period of 2023 to 2030. The model projects that Scenario 1 would avert 8741 DALYs over the period of 2023 to 2030; however, it is not cost-effective against the South African cost-effectiveness threshold with an ICER per DALY averted of USD 21,006. While Scenario 3 and 4 included the administration of more vaccine doses and averted more symptomatic cases of hepatitis A, these scenarios were absolutely dominated owing to the population being infected before vaccination through the mass campaigns at older ages. The model was highly sensitive to variation of access to liver transplant in South Africa. When increasing the access to liver transplant to 100% for the baseline and Scenario 1, the ICER for Scenario 1 becomes cost-effective against the CET (ICER = USD 2425). Given these findings, we recommend further research is conducted to understand the access to liver transplants in South Africa and better estimate the cost of liver transplant care for hepatitis A patients. The modelling presented in this paper has been used to develop a user-friendly application for vaccine policy makers to further interrogate the model outcomes and consider the costs and benefits of introducing routine hepatitis A vaccination in South Africa.

Hepatitis A virus seroprevalence among children and adolescents in a high-burden HIV setting in urban South Africa

Hepatitis A virus (HAV) infection is one of the most important global causes of viral hepatitis. Recent reviews suggested that HAV endemicity in South Africa could shift from high to intermediate. A hospital-based HAV seroprevalence study was conducted between February 2018 and December 2019 in Pretoria, South Africa. Systematic sampling was performed on children and adolescents (1-15 years) who attended outpatient services. Participants with a known HIV status and valid HAV serology results were included. Of the 1220 participants, the median age was 7 years (IQR: 4-11), with 648 (53.11%) males and 572 (46.89%) females. Of 628 (51.48%) HIV-infected participants, most (329, 71.83%) were both immunologically and virologically controlled or had low-level viremia (74, 16.16%). Almost three-quarters (894, 73.28%) were living in formal dwellings, and just over half (688, 56.39%) had access to clean water sources inside the house. Increasing age was associated with testing HAV IgG-positive (OR 1.25; 95% CI 1.20-1.30, p < 0.001), with 19.8% of participants one year of age compared with 86.7% of participants 15 years of age. This study suggests that South Africa has an intermediate HAV seroprevalence, with rates < 90% by 10 years of age (68.6%). Increased age and informal dwellings are statistically associated with HAV seropositivity, while HIV status does not significantly influence HAV seropositivity.