Modelling backs a universal hepatitis B birth dose for South Africa's newborns

A modelling study in The Lancet Global Health concludes that South Africa should add a universal hepatitis B birth dose — one given to every newborn — to its current programme, because doing so would avert the most disease and, despite costing the most to run, come out as the most cost-effective option the authors examined [s1]. The finding is a qualified endorsement of the World Health Organization's long-standing recommendation, which South Africa has so far chosen not to follow in full [s1].

South Africa had an estimated hepatitis B prevalence of 4·7–6·0% in 2022 [s1]. In 2023 it introduced a targeted, or selective, hepatitis B birth-dose policy: only infants born to mothers with confirmed hepatitis B positivity are eligible for the birth dose, which is given on top of peripartum antiviral prophylaxis offered to those mothers from the second or third trimester of pregnancy [s1]. That design departs from the WHO recommendation that all newborns receive a hepatitis B birth dose within 24 hours of delivery, given that mother-to-child transmission is the predominant route of infection where the virus circulates steadily [s2].

What the model compared

The authors used a validated model of hepatitis B transmission, disease progression and mortality to simulate South Africa's ongoing epidemic, and ran it forward over a 2025–2100 time horizon [s1]. They compared three strategies against a baseline of no birth-dose coverage: the current South African policy of selective antiviral prophylaxis plus a selective birth dose; a universal birth-dose-only policy; and the WHO-endorsed combination of selective antiviral prophylaxis plus a universal birth dose [s1]. Costs were reported in consumer-price-index-adjusted 2024 rand and outcomes discounted at 3% a year [s1]. The work was funded by the Vaccine Impact Modelling Consortium [s1].

The efficiency paradox at the centre of the result

The headline numbers look, at first, like an argument for the status quo. South Africa's current selective policy is extraordinarily efficient on a per-dose basis: the model put the number of infants needing to be vaccinated to avert one vertically acquired chronic hepatitis B infection at six, with a 95% uncertainty interval of three to 15 [s1]. That is what targeting achieves — the doses go only to the babies known to be at highest risk.

By comparison, a universal birth-dose-only policy required 462 vaccinations per chronic infection averted (223–1,479), and the WHO-endorsed selective-prophylaxis-plus-universal-dose combination required 77 (38–240) [s1]. On this metric alone, the current policy wins by a wide margin.

But number-needed-to-vaccinate measures efficiency, not total benefit — and it is precisely the doses that look "wasted" under a universal policy that catch the infections a screening-based programme misses. Screening is imperfect; some mothers with hepatitis B are not identified, and their infants are not offered the selective dose. A universal dose covers those infants regardless. So the model found that the selective-prophylaxis-plus-universal-dose policy, despite incurring the greatest programmatic costs, averted the greatest disease burden and was the most cost-effective option at a willingness-to-pay threshold of 0·5 times per-capita gross domestic product, or 57,281 rand [s1].

What it means, and what it does not

The authors' interpretation is that their findings support implementing a universal birth-dose policy alongside South Africa's current elimination efforts, rather than replacing the antiviral prophylaxis that protects the highest-risk infants [s1]. The two are complementary: prophylaxis for known cases, a universal dose as the backstop for the ones screening misses.

The context makes the case more than academic. Sub-Saharan Africa carries an estimated 60% of the global burden of viral hepatitis, and vaccination is central to WHO's targets of a 90% reduction in incident cases and a 65% reduction in mortality by 2030 [s2]. A birth dose is one of the few interventions that acts at the exact moment vertical transmission occurs.

The result carries the standard caveats of any modelling analysis: it rests on a validated model, but a model nonetheless, and its cost-effectiveness verdict is anchored to a specific willingness-to-pay threshold and to South African prices in 2024 rand [s1]. It also speaks to South Africa's epidemiology and health system, not automatically to other countries with different prevalence, screening coverage or delivery costs. What it does establish is that the intuitive efficiency of a tightly targeted policy — six vaccinations per infection averted — is not the same as the greatest health return, and can obscure the infections a screening net lets through.

South Africa's decision on whether to move to a universal birth dose is a policy question, not a settled one, and this analysis is an input to it rather than the last word. But the modelled answer is unusually clear about the direction it points.

This article is informational and is not medical advice.

Sources

• [s1] "Cost-effectiveness of the hepatitis B birth-dose vaccine in South Africa: a mathematical modelling analysis," The Lancet Global Health, 2 September 2026. https://doi.org/10.1016/j.langlo.2026.103975
• [s2] "Economic case for universal hepatitis B birth dose vaccination in South Africa" (Comment), The Lancet Global Health, 2 September 2026. https://doi.org/10.1016/j.langlo.2026.104018