Almost two-thirds of Africans had developed coronavirus antibodies by last September, indicating the continent’s infection rate has been much higher than official figures show, the World Health Organisation (WHO) said on Thursday. It estimated that there had been 800-million infections by the end of the third quarter of 2021, 97 times higher than the 8.2-million recorded cases.
Exposure to SARS-CoV-2, the virus that causes Covid-19, soared from 3% in June 2020 to 65% in September 2021, the WHO concluded in a meta-analysis of 151 seroprevalence studies published on the preprint server MedRxiv ahead of peer review. Since vaccination coverage in Africa was still very low at this stage, the majority of people who had developed antibodies to the virus would have done so from natural infection.
The WHO’s findings are broadly in line with a SA study led by Wits dean of health Shabir Madhi, which found more than 70% of people living in Gauteng had developed coronavirus antibodies from prior infection or vaccination by December 2021.
Undercounting of coronavirus infections was a worldwide phenomenon because so many cases were asymptomatic, but it was particularly acute in Africa due to its limited testing capacity, said WHO-Africa regional head Matshidiso Moeti. Testing has been severely rationed in Africa and has focused on travellers and the sickest among symptomatic patients. Worldwide, the true number of infections is estimated to be 16 times greater than the number of reported cases.
The study found wide variations between African regions, with seroprevalence ranging from 56.1% in Southern Africa to 75.5% in Middle Africa by the end of the third quarter last year. The WHO noted that the proportion of people with coronavirus antibodies surged after the emergence of the coronavirus variants Beta and Delta, which were each more transmissible than the strains they displaced.
Moeti said routine testing was vital for managing the coronavirus pandemic, even as the latest Omicron-driven wave of infections eased.
“Testing enables us to track the virus in real-time, monitor its evolution and assess the emergence of new variants. Countries must ramp up testing, contact tracing and surveillance so we can stay a step ahead of Covid-19,” she said.
The WHO’s analysis provided clear evidence of the continued circulation of Covid-19 in Africa, she said, urging people to get inoculated.
Vaccine coverage in Africa, which initially struggled to obtain supplies, remains lower than in other regions of the world. Only 15.8% of its population is fully immunised, according to the Africa Centre for Disease Control and Prevention.
“The risks of more lethal variants emerging which overwhelm immunity gained from past infections cannot be brushed aside,” said Moeti.
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