Nigeria’s Lassa fever deaths spike 14% in 2023

…despite 1.6% dip in fatality ratio

A new report by the Nigeria Centre for Disease Control (NCDC) has shown that Lassa fever deaths in Nigeria rose by 14.2 percent in 2023 from 1055 deaths recorded in 2022.

This is despite a 1.6 percent decrease in the case fatality ratio seen last year.

As of week 51 of 2023, the number of new confirmed cases increased from 10 in week 50 to 26 cases, all gathered from Bauchi, Ondo, Taraba, and Plateau States.

Cumulatively, 215 deaths have been reported with a case fatality rate of 17.5 percent which is lower than the rate for the same period in 2022 (17.9 percent).

In total for 2023, 28 states have recorded at least one confirmed case across 121 Local Government Areas.

About 77 percent of all confirmed Lassa fever cases were reported from Ondo, Edo, and Bauchi, while 23 percent were reported from 25 states with confirmed Lassa fever cases.

Of the 77 percent confirmed cases, Ondo reported 35 percent, Edo 28 percent, and Bauchi 14 percent.

The predominant age group affected is between 21 and 30 years.

Two new Healthcare workers were affected in the reporting week 51.

Vaccine

In 2020, the biggest research on Lassa fever prevalence in West Africa, run on $26 million funding, was inaugurated with a focus on tracking the exact scale of prevalence and applying the data to boost the potential of a vaccine.

But the result of the effort is yet to be unveiled.

The Coalition for Epidemic Preparedness Innovations (CEPI) and the Nigeria Lassa Fever Research consortium in December jointly launched the programme, ‘Enable’. It involved a total of 26, 000 enrollees from Nigeria, Benin, Guinea, Liberia, and Sierra Leone.

About 4,800 Nigerians were enrolled as first participants under the Nigerian component of the programme dubbed ‘Nigeria Lassa Epidemiology’ (NiLE) study.

The findings were expected to answer questions on Lassa virus circulation and support planning for where clinical trials of developed vaccines can take place.

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 standardized diagnoses.

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 an infected rodent host or from person-to-person contact via bodily fluids.

The NCDC admitting that the actual incidence rate in Nigeria remains uncertain estimates that case fatality rates range between three per cent and 42 per cent but have remained between 20 per cent and 25 per cent over the last two years.

In addition to establishing the rate of infection, CEPI 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, in a statement on its website.

Data gathered from the research will serve as a crucial guide for designing 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,” Richard Hatchett, chief executive officer of CEPI.

Chikwe Ihekweazu, the former 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.