The ENABLE 1.5 Lassa Research Programme is scaling up study to address gaps in knowledge on Lassa fever, its connection with malaria, and community readiness for forthcoming vaccines.
The study, funded by the Coalition for Epidemic Preparedness Innovations, CEPI, was made available to the News Agency of Nigeria on Sunday.
NAN reports that the study commenced in late 2024 and will run till mid-2026 across Liberia, Nigeria, and Sierra Leone, with significant scientific and public health goals.
The prospective cohort study recruited 5,000 participants, at least 1,000 per site, monitored closely for a year to measure Lassa virus incidence, malaria co-infection and long-term complications, including permanent hearing loss.
This phase of the study builds on ENABLE 1.0 (2021–2023), which enrolled more than 23,000 participants in Benin, Guinea, Liberia, Nigeria and Sierra Leone, revealing important data on Lassa virus exposure and distribution patterns.
The study said that the earlier phase recorded an overall Lassa virus seroprevalence of about 30 per cent, with Edo State, Nigeria, reporting the highest incidence rate, 1.9 cases per 1,000 persons in surveillance findings.
It disclosed that children were as vulnerable to Lassa fever as adults.
“Mild cases are often missed, while malaria coinfection rates in Lassa patients remain poorly studied, necessitating targeted data gathering and analysis.
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“ENABLE 1.5 will determine symptomatic infection rates confirmed by RT-PCR testing, measure malaria co-infection among Lassa patients, and assess sensorineural hearing loss incidence in survivors to inform vaccine trials and health interventions,” it said.
The study would also evaluate community perceptions of Lassa vaccination and willingness to join future clinical trials, using participatory approaches to improve acceptance and build trust in targeted populations.
To reduce participant dropout, the study said that researchers would involve community health workers and survivors as advocates, alongside sensitisation campaigns on rodent control, environmental sanitation and insecticide-treated mosquito net usage in high-risk communities.
Communities from ENABLE 1.0 would receive updates on past findings, ensuring transparency and strengthening local relationships, while random household selection in Lassa hotspots will ensure a balanced representation across five age categories.
The study said that participants would undergo regular check-ups, blood tests and hearing assessments.
It said that suspected cases would be tested for both diseases, and confirmed cases referred promptly to treatment centres following national health guidelines.
It said that survivors would be followed for months to monitor recovery progress, detect delayed complications and collect valuable information about the long-term health and socioeconomic impact of the disease on affected individuals.
NAN recalls that Lassa fever is an acute viral haemorrhagic illness mainly spread by contact with infected rodent urine or droppings. Severe cases can cause multi-organ failure, with fatality rates reaching 70 per cent.
Although historically peaking during dry seasons, recent trends suggest year-round transmission in Nigeria, Liberia, and Sierra Leone, driven potentially by climate change, urbanisation and other evolving socio-environmental factors influencing disease patterns.
CEPI said that ENABLE 1.5 would generate robust evidence for late-stage vaccine trials, inform delivery strategies and strengthen regional outbreak preparedness and response for Lassa fever and associated health challenges.
“By understanding the true burden, including mild cases and paediatric infections, we can better target interventions and prepare effectively for the introduction of future vaccines,” CEPI said in its statement.
The findings are expected to shape West Africa’s response to a disease that has persisted for decades, ensuring that when vaccines become available, communities will accept and benefit from them. NAN
