The biggest research on Lassa fever prevalence in West Africa, run on $26 million funding, has been inaugurated with a focus on tracking the exact scale of prevalence and applying the data to boost the potential of a vaccine.
The Coalition for Epidemic Preparedness Innovations (CEPI) and the Nigeria Lassa Fever Research consortium in December jointly launched the programme, ‘Enable’. It involves a total of 26,000 enrollees from Nigeria, Benin, Guinea, Liberia, and Sierra Leone.
The programme has already enrolled 4,800 Nigerians as first participants over the first week of December under its Nigerian component dubbed ‘Nigeria Lassa Epidemiology’ (NiLE) study.
The findings are expected to answer questions on Lassa virus circulation and support planning for where clinical trials of developed vaccines can take place.
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The facilitators suspect that the true picture of the epidemic prevalence is higher than the current estimate of about 300,000 cases yearly occurring in West Africa, given the factors of variation, severity in symptoms and the dearth of standardised diagnoses.
Nigeria, for instance, confirmed over 600 cases, the largest record, and over 170 deaths in 2018, according to the Nigeria Centre for Disease Control (NCDC).
The viral disease associated with bleeding fever, high morbidity and high fatality was reported first in Borno, a northern Nigerian state.
The disease spreads through coming into contact with infected rodent host or from person-to-person contact via body fluids.
The NCDC, admitting that the actual incidence rate in Nigeria remains uncertain, estimates that case fatality rates range between 3 percent and 42 percent but have remained between 20 percent and 25 percent over the last two years.
In addition to establishing the rate of infection, CEPI in a statement on its website says the research will note age and gender disparity in people infected and provide a more accurate overview of the proportion of asymptomatic and symptomatic cases.
Data gathered from the research will serve as a crucial guide for the design of future late-stage efficacy trials to evaluate potential Lassa vaccine candidates.
Already, two vaccines developed by Inovio and Themis Bioscience with the backing of CEPI funding qualified for clinical trials in 2019.
“Enable is a landmark collaboration and the largest study ever to be undertaken on Lassa fever. In addition to providing crucial data on the prevalence and spread of the disease the work will also help inform CEPI-supported Lassa vaccine efficacy studies, which we hope can be launched in the next few years,” said Richard Hatchett, chief executive officer, CEPI.
Chikwe Ihekweazu, director-general of NCDC, described the huge investment and collaboration as an opportunity to provide a deeper clarity on the burden of Lassa fever in the largest African economy and other African countries affected.
“We are very proud of the rapid investment. In 2019, when NCDC hosted the first-ever Lassa fever International Conference in Abuja, Nigeria, we identified the limited research activities in this area as a challenge and an opportunity,” he said.
Method
Rates of potential infections will be scaled in participants through standard observational measures such as active and passive surveillance.
Under the former, a repeat health status assessment of participants will be conducted by a field worker through home visits or phone meetings.
Passive surveillance will involve encouraging participants to report potential illness or to self-present at a health facility, allowing the suspected or confirmed case to be recorded.
According to CEPI, the study design was devised by all study site partners who will be running the programme across West Africa.
All will follow the same core protocol and methodologies to allow for standardised recording and comparability of Lassa fever incidence data.
A subset of those enrolled in Nigeria and the other Enable programme study sites will take part in an additional assessment to look at the prevalence of Lassa fever antibodies – biomarkers of the immune response.
This will act as an indicator to better guide estimates on how many individuals in the general population are likely to have previously been infected with the virus and are, at present, protected against the disease.
