Nearly two-thirds of Africans have already been infected with SARS-CoV-2 — the virus responsible for COVID-19, WHO said, announcing the release of a new assessment of virus seroprevalence on the continent.  The analysis, a systematic review of some 150 studies, was published on the pre-print server, medRXiv.org.

Addressing a press briefing on Thursday, Dr Matshidiso Moeti, WHO Regional Director for Africa said the WHO study demonstrates that there had been some 800 million infections as of September 2021 – nearly 100 times greater than the 8.2 million cases reported at the time.   

To arrive at the estimate, WHO synthesized the results of 151 studies published on virus seroprevalence in Africa between January 2020 and December 2021. It found that blood samples with SARS-CoV-2 antibodies skyrocketed from about 3% in June of 2020 to 65% by September of 2021. Exposure to the virus rose sharply following the emergence of the Beta and the Delta variants, she said. And that data doesn’t even consider the big Omicron wave of infections that hit countries in southern Africa in early December and continued into early 2022. 

The study is the first systematic review of disease incidence in the region that has consistently shown the lowest COVID infection rates – but is also plagued by an overall lack of reporting of health data generally on major diseases as well as deaths. 

The study was carried out by a team of scientists from WHO’s African Regional Office, WHO Headquarters in Geneva, and a group of Canadian scholars from McGill University, University of Calgary and elsewhere. 

It’s unusually broad in scope, covering data from some 22 of the continent’s 54 WHO member states (the African Union counts the disputed Sahrawi Arab Democratic Republic in Western Sahara as its 55th member). More significantly, the studies cover countries that include some 71% of the continent’s roughly 1 billion inhabitants. And it includes data from all of Africa’s major geographical regions – all of which had very different experiences with COVID response.   

The Ghana experience

One of the West African studies considered in the report was carried out in Ghana, by a research team including Dr Irene Owusu Donkor, a postdoctoral fellow at Ghana’s Noguchi Memorial Institute for Medical Research.

Appearing at the briefing, Donkor noted that her team conducted the study between February and December 2021 to measure seroprevalence of COVID-19 among 6,000 individuals spread across Ghana’s rural and major urban areas. The results yielded a 68% rate of seropositivity, which means that 68% of the people tested had been exposed to the SARS-CoV-2 virus. 

“We also saw that males and females have the same levels of exposure. However, we saw that people aged between 15 to 19 years were the most exposed,” Donkor told journalists.

Testing policy responsible for significant underreporting

Moeti attributed the significant underreporting in Africa to the prioritization of symptomatic individuals for testing, due in part to the shortage of COVID tests and challenges in rolling out COVID tests very widely at key stages of the pandemic. She said this meant that Africa’s reported cases are not true reflection of infections considering not every infected person shows symptoms.

“In Africa, the focus was very much on testing people who were symptomatic when there were challenges in having access to testing supplies. We are under-representing the true number of people who have been exposed and infected by the virus,” she told journalists. 

She however noted that this is not peculiar to Africa as experts presume that there has been significant underreporting of COVID infections in countries.  For instance, while there have been about 495 million reported COVID infections worldwide, to date, the latest WHO estimates, are that some 45.2% of the world’s 7.9 billion people were likely infected by the virus as of September 2021, she said.

“We do know, however, that fewer studies are conducted in Africa than elsewhere. The production of accurate data in Africa is further complicated, because 67% of people with COVID-19 on the continent have no symptoms,” Moeti added. 

Donkor called for more seroprevalence studies and to continue with routine surveillance to ensure that cases are quickly detected while also using the waves that have been seen so far with the various variants to put the pandemic in check.

Moeti told Health Policy Watch that the implication of this finding is the need for the expansion of surveillance for COVID-19 on an ongoing basis in African countries.

“It’s very important for governments and partners and even populations to know the actual situation — to know something that is closer to the true situation because it is this that’s going to guide the preparedness and the adjustment of prevention measures as the situation continues to evolve,” she told Health Policy Watch.

WHO publication of global estimate of COVID cases, still pending 

WHO is supposed to be preparing for the publication of a formal global estimate of actual COVID cases, which highlights the worldwide problems with COVID under-reporting at the end of this month, sources told Health Policy Watch.  Originally that publication was to have been issued at the end of March, but it has been delayed, the sources said.  

As with the publication of any WHO data, political issues involving member state agreement can lead to the delay, and even censorship, of what are supposed to be professional WHO assessments.