Contact without protection: high antenatal attendance, minimal hepatitis B testing in Nigerias mother-to-child prevention cascade -- how far from elimination?

Hepatitis B is a leading preventable cause of liver cancer, and in high-burden settings most chronic infection is acquired around birth. Nigeria carries Africas largest hepatitis B burden. Preventing mother-to-child transmission requires a chain of antenatal steps: testing pregnant women, acting on the result, and vaccinating the newborn. No nationally representative study has assembled these into a single prevention cascade. We built the first national hepatitis B mother-to-child prevention cascade for Nigeria and measured how far it falls from the World Health Organizations triple-elimination targets. We analysed the 2023-24 Nigeria Demographic and Health Survey, the first Nigerian survey to carry both a maternal hepatitis B module and infant birth-dose records. Among 13,341 women with a most recent live birth in the preceding three years, each linked to that childs immunisation record, we estimated coverage at each cascade step (antenatal attendance, hepatitis B testing in antenatal care, result received, and the infant birth dose) using complex-survey methods, and examined patterning by wealth, education, residence, travel time, and region. Although 72% of mothers attended antenatal care, only 12.3% (95% CI 11.4-13.2) were tested for hepatitis B there, and among the few tested almost all received a result: the loss fell at testing, not at result-return. The infant birth dose reached 55.0% (53.1-56.9), 35 points below target, and ran at a level unrelated to maternal testing, consistent with universal, non-targeted delivery; place of delivery, not maternal testing, was the dominant correlate of an infant receiving it. Both steps were steeply patterned: antenatal testing ranged from 2.6% in the poorest wealth quintile to 32.4% in the richest, and was lowest in the North-West, the zone with Nigerias highest prevalence. Nigeria already reaches most mothers through antenatal care but rarely uses that contact to test for hepatitis B, and the universal birth dose is only half delivered. The country is far from elimination, and furthest where the virus is commonest. Integrating hepatitis B testing into antenatal care, made free and weighted toward the highest-burden north, would convert contact already achieved into protection.