A woman in a nurse's uniform and mask receives a vaccination.

A health-care worker in Lusaka is vaccinated against COVID-19.Credit: Xinhua/Shutterstock

Almost one-third of more than 1,000 bodies taken to a morgue in Lusaka in 2020 and 2021 tested positive for SARS-CoV-2, implying that many more people died of COVID-19 in Zambia’s capital than official numbers suggest1. Some scientists say that the findings further undermine the ‘African paradox’, a narrative that the pandemic was less severe in Africa than in other parts of the world.

This idea arose after health experts noticed that sub-Saharan nations were reporting lower case numbers and fewer COVID-19 deaths than might be expected. But researchers say that the findings from Zambia could reflect a broader truth — that a deficit of testing and strained medical infrastructure have masked COVID-19’s true toll on the continent. The findings have not yet been peer reviewed.

Ignoring the true extent of COVID-19 in Lusaka and beyond “is so wrong. People were ill. They’ve had their families destroyed,” says co-author Christopher Gill, a global-health specialist at Boston University in Massachusetts. One of his colleagues in Zambia died of COVID-19 while working on the project.

“It’s not hypothetical to me,” says Gill.

Missing COVID cases

When SARS-CoV-2 began spreading globally, many health researchers worried that the virus would devastate sub-Saharan Africa. But the surprisingly low numbers of reported COVID-19 cases in the region led to the perception “that severe debilitation and deaths caused by COVID-19 were somehow less in Africa compared to other continents”, says Yakubu Lawal, an endocrinologist at the Federal Medical Centre Azare in Nigeria.

Lawal and other scientists speculated2 that the relative youth of Africa’s population might have helped to spare the continent, but also suspected that official numbers were under-reported. The question was by how much.

Seeking answers, Gill and his colleagues in Zambia tested bodies in one of Lusaka’s largest morgues for SARS-CoV-2 over several months in 2020 and 2021. Test positivity was 32% overall — and reached around 90% during the peak of the waves caused by the Beta and Delta variants. Moreover, only 10% of the people whose bodies were found to contain the virus after death had tested positive while still alive. Some had falsely tested negative, but most had never been tested at all.

Although Gill and his colleagues can’t confirm that all of these people died of COVID-19, the results still stand in sharp contrast to official numbers. So far, there have been fewer than 4,000 confirmed COVID-19 deaths in Zambia, a country of around 19 million people. Separate findings published on 10 March suggest that Zambia’s ‘excess’ deaths — those above what would usually be expected — from 1 January 2020 to the end of 2021 exceeded 80,0003.

The Lusaka numbers mesh with statistics from South Africa, where a 2021 study found that only 4–6% of SARS-CoV-2 infections in two communities were officially documented4. Further study of the same communities showed that 62% of study participants had been infected at least once from July 2020 to August 20215. Co-author Cheryl Cohen, an epidemiologist at the University of the Witwatersrand in Johannesburg, South Africa, says that many of these infections were asymptomatic, but that people with symptoms might also have gone undetected because of the cost and difficulty of getting tested.

Gill suspects that a major reason for the gap between his results and official counts is that most people in Zambia who die of COVID-19 do so outside medical care. Four out of five people tested in the study were never admitted to a hospital; the majority of unreported infections were in people living in Lusaka’s lowest-income neighbourhoods.

“Nobody’s vaccinated. Nobody has masks. Nobody has access to the medical care they need,” says Gill. “We’re in a population that is already stressed and unhealthy, and then — bam! In comes COVID.”

Vast variation

But not everyone is convinced that the Lusaka findings invalidate the idea of the African paradox. In Ethiopia, for instance, “our experience is people get infected with the virus, are asymptomatic or have mild symptoms, and recover”, says Amare Abera Tareke, a physiologist at Wollo University in Dessie. “While it is difficult to ignore the current finding, we have to take it cautiously.”

Gill worries that the idea that Africa was spared the worst of the pandemic might have led people to take unnecessary risks or contributed to “the lack of urgency” in supplying African nations with vaccines.

“I suppose this could be unique to Lusaka,” he says, “But boy, you’d really have to try hard to explain why.”