Two Gambians have been found to be re-infected by variants of Sars-COV-2, the virus that causes COVID-19, making them the first of such cases in the African sub-region.
The study by researchers including Bakary Sanyang, Oghenebrume Wariri, and others from the Medical Research Council Unit of The Gambia at the London School of Hygiene and Tropical Medicine and the National Public Health Laboratories, Kotu in The Gambia published on June 03 in The Lancet confirmed that the cases of reinfections was among two healthy Gambian individuals aged 31 years and 36 years, occurring within a time frame of 5 months and 6 months, respectively.
Using genomic analysis, the researchers found that both individuals had mild symptoms during the second infection that lasted less than one week. During the initial infection, one individual, they said, had mild symptoms, whereas the other was asymptomatic, having been tested as a contact of a positive case.
“In summary, our data conclude that at least two reinfections have occurred in The Gambia. These events have occurred in healthy young individuals infected with similar viral variants in the first and second episode,” the researchers wrote, noting also that “If reinfections with similar strains are possible, herd immunity in west Africa could take longer than expected as a large majority of cases are asymptomatic or with mild disease and these probably develop weaker immune responses.”
They also expressed concern that, in the absence of widespread vaccination, reinfections could become more common when the new variants becoming predominant in the region, raising the urgent need for Community-based immunological studies.
The Gambia, West Africa’s smallest country, reported 4712 cases and 150 deaths by March 1, 2021. According to the study, 460 SARS-CoV-2 genomes from confirmed cases had been sequenced in the country, with 430 (93·5%) genomes already submitted on the GISAID database, a global science initiative and primary source that provides open-access to genomic data of influenza viruses and the coronavirus.
Elsewhere in the United States, researchers from the University of Missouri School of Medicine and MU Health Care in their recent study have shown that the re-infection rate of COVID-19 among more than 9,000 U.S. patients with severe COVID-19 was less than 1%.