Nigeria's Yellow Fever Outbreak Turns Deadly
The World Health Organization (WHO) confirmed yellow fever cases across several states in Nigeria. From January to August 31, 2021, a total of 1,312 suspected cases were reported across 36 States and the Federal Capital Territory (FCT).
A total of 45 blood samples were sent to the Institut Pasteur in Dakar (IPD), and 31 samples tested positive by the Plaque reduction neutralization test (PRNT).
Of these 31 PRNT positive cases, twelve cases had a history of yellow fever vaccination.
Two deaths were reported among the remaining 19 non-vaccinated PRNT positive cases (Case fatality ratio: 11%).
And the investigations into the remaining PRNT-positive cases are ongoing.
According to WHO-UNICEF 2020 estimates, the national immunization coverage for yellow fever was 54% in 2020, which is below the threshold of 80% necessary to protect against outbreaks.
In addition, yellow fever surveillance is sub-optimal.
Not all suspected cases are documented, presumptive positive cases are not always investigated, and investigations of confirmed cases and confirmatory testing results are delayed. Additionally, vaccination status, which is critical for interpretation of laboratory results and case confirmation, may not be reported as part of the investigation.
Accelerated phased vaccination campaigns are planned to cover the entire country by 2024.
Furthermore, the WHO recommends vaccination against yellow fever for all international travelers from 9 months of age going to Nigeria. Nigeria requires a yellow fever vaccination certificate for most travelers as a condition of entry.
Yellow fever vaccines recommended by WHO are safe, highly effective, and provide life-long protection against infection. However, a booster dose of an approved yellow fever vaccine cannot be required of international travelers as a condition of entry, says the WHO.
Previously, the U.S. CDC issued a Level 2 Travel Advisory regarding Nigeria's yellow fever outbreak. The CDC said on September 30, 2021, 'travelers to Nigeria should take steps to prevent yellow fever by getting vaccinated at least ten days before travel and taking steps to prevent mosquito bites.'