HIV and Hepatitis Burden Laid Bare Among Women Who Inject Drugs in Mozambique

Women who inject drugs in Mozambique carry a heavy and unevenly distributed burden of HIV and viral hepatitis, according to a new cross-sectional study published in BMC Public Health. Drawing on data collected between July 2023 and March 2024 in five of the country’s largest cities, researchers from Mozambique’s Instituto Nacional de Saúde and Portugal’s Instituto de Higiene e Medicina Tropical estimated that 28.6 percent of women who inject drugs are living with HIV, while 19.7 percent carry antibodies against hepatitis C virus and 5.3 percent test positive for hepatitis B surface antigen. The findings, drawn from a subgroup analysis of a national bio-behavioral survey, offer one of the clearest quantitative portraits yet of how blood-borne infections cluster among a population that has long remained largely invisible in Mozambican health statistics.

The study was embedded in the second round of a bio-behavioral survey of people who inject drugs of any gender, conducted in Maputo, Beira, Tete, Quelimane and Nampula. From the larger survey sample, the researchers isolated 524 women who inject drugs, each of whom completed a structured questionnaire covering sociodemographic characteristics, drug use patterns, sexual behavior and healthcare access, and provided samples for rapid point-of-care testing for HIV, hepatitis B surface antigen and hepatitis C antibodies. Because people who inject drugs are difficult to reach through conventional household surveys, the team used respondent-driven sampling, a chain-referral technique in which initial participants, or seeds, recruit peers from their own social networks, and the resulting recruitment chains are statistically weighted to reduce the biases introduced by network-based recruitment.

Respondent-driven sampling allowed the investigators to calculate weighted prevalence estimates that better reflect the underlying population of women who inject drugs in each city rather than merely the convenience sample they managed to enroll. For HIV, the weighted prevalence of 28.6 percent came with a wide 95 percent confidence interval of 15.5 to 41.6 percent, a reflection of both the subgroup’s size and the variability of infection across cities. The weighted prevalence of hepatitis C antibodies, 19.7 percent, carried an even wider interval of 3.1 to 36.2 percent, underscoring how heterogeneous the epidemic is across urban settings. Hepatitis B surface antigen positivity, at 5.3 percent, was comparatively narrow at 3.4 to 7.3 percent.

Unadjusted analyses revealed striking patterns. HIV prevalence peaked among women aged 25 to 34 years and rose markedly with both age and the duration of injection drug use, a relationship consistent with cumulative exposure risk over years of sharing needles, syringes, cookers or other injection paraphernalia. Geography mattered as well: prevalence was highest in Maputo City, the capital and largest urban center, suggesting that dense urban drug markets and sexual networks may amplify transmission. The hepatitis C picture mirrored this concentration of risk, since the virus, which is transmitted efficiently through blood-to-blood contact, is a sensitive marker of unsafe injection practices accumulated over time.

To move beyond simple associations, the researchers applied modified Poisson regression with robust standard errors, a modeling approach well suited to binary outcomes such as infection status because it yields adjusted prevalence ratios that are easier to interpret than odds ratios when outcomes are common. After adjustment for confounding, two factors remained independently associated with HIV infection: older age, with women aged 35 years or older showing an adjusted prevalence ratio of 11.9 compared with those aged 16 to 17 years, a confidence interval of 4.0 to 35.6, and residence in Maputo. Conversely, secondary or higher education and the absence of recent symptoms of sexually transmitted infections were associated with lower HIV prevalence, pointing to the intertwined roles of educational attainment, sexual health and injection-related risk in shaping vulnerability.

The magnitude of the age effect deserves emphasis. An adjusted prevalence ratio of nearly twelve means that, after accounting for other measured factors, the oldest women in the sample were roughly twelve times more likely to be living with HIV than the youngest. This gradient is consistent with the natural history of an epidemic that has had years to accumulate in older cohorts of people who inject drugs, but it also signals that women who began injecting more recently are not spared risk; rather, they represent an opportunity for early intervention before infection becomes established in their networks.

The study also traced the HIV care continuum among the women found to be living with the virus, and the results reveal both progress and a persistent bottleneck. Among women who inject drugs living with HIV, 85.0 percent were aware of their status, a comparatively high level of knowledge that likely reflects the reach of community-based testing. Of those aware, 86.6 percent were on antiretroviral therapy, and of those on treatment, 75.7 percent had achieved viral suppression. Each stepwise attrition may seem modest, but compounded, they mean that only a fraction of all HIV-positive women who inject drugs in these cities are virally suppressed, the condition that both preserves individual health and prevents onward transmission.

The authors highlight the gap between antiretroviral therapy initiation and viral suppression as a priority for further investigation. Retention in care, adherence support, stigma within health facilities, interruptions in drug supply and the competing demands of daily survival for women who use drugs can all erode the effectiveness of treatment programs. Because viral suppression is the endpoint that matters most for both morbidity and prevention, understanding why nearly a quarter of women on treatment have not achieved it is a research question with direct programmatic consequences.

The hepatitis findings carry their own implications. A hepatitis B surface antigen prevalence of 5.3 percent places the surveyed women in a range consistent with intermediate endemicity, raising questions about access to hepatitis B vaccination, which in Mozambique is delivered through routine childhood immunization but may have missed adults now in their twenties and thirties. The anti-HCV prevalence of 19.7 percent, meanwhile, points to substantial exposure to hepatitis C, a curable infection since the advent of direct-acting antiviral agents, yet one that remains undiagnosed and untreated in most low-resource settings. Integrating hepatitis B and C testing, vaccination where indicated, and treatment into existing HIV and harm-reduction services would allow a single point of contact to address all three blood-borne viruses.

The study’s conclusions converge on a clear set of priorities: expanded harm-reduction services, including sterile injecting equipment and opioid substitution therapy where feasible; integrated testing and treatment for HIV, hepatitis B and hepatitis C; and prevention efforts targeted to the cities and age groups bearing the heaviest burden, particularly Maputo and women in mid-adulthood with long injection histories. Funded by the Global Fund to Fight AIDS, Tuberculosis and Malaria and approved by Mozambique’s national ethics bodies, the survey demonstrates that even in settings where women who inject drugs are few in number relative to men, their infection burden is severe enough to demand dedicated attention. Without such attention, the authors warn, the gaps documented here will continue to translate into preventable infections and preventable deaths.

Subject of Research: Prevalence and risk factors of HIV, hepatitis B, and hepatitis C among women who inject drugs in Mozambique

Article Title: Prevalence and risk factors of HIV, HBV, and HCV among women who inject drugs in five Mozambican cities: a subgroup analysis of a cross-sectional biological and behavioral survey, 2023–2024

Article References: Banze, Á. R., Muleia, R., Nuvunga, S., Craveiro, I., Seabra, S. G., & Baltazar, C. S. (2026). Prevalence and risk factors of HIV, HBV, and HCV among women who inject drugs in five Mozambican cities: a subgroup analysis of a cross-sectional biological and behavioral survey, 2023–2024. BMC Public Health. https://doi.org/10.1186/s12889-026-29934-1

Image Credits: AI Generated

DOI: 10.1186/s12889-026-29934-1

Keywords: HIV, hepatitis B, hepatitis C, women who inject drugs, Mozambique, harm reduction, respondent-driven sampling, antiretroviral therapy, viral suppression, cross-sectional survey, public health, Prevalence