COVID-19 in Africa: Milder than expected — but why?

Hundreds of thousands or even millions of deaths and serious infections causing the collapse of already shaky health care systems —this is how experts imagined the effect of the coronavirus pandemic in most African countries.

But, more than four months later, one can say that this horror scenario has not materialized.

While rates of infection and death on other continents have sometimes exploded in recent months, Africa has been spared a high COVID-19 mortality rate — and this despite the fact that people in cities like Dakar and Lagos live under very crowded conditions, with many suffering from poverty and a lack of basic hygienic facilities.

Scientists have been examining the possible reasons for the mild course of the pandemic on the continent.

In an analysis for the journal Science in August, one group of researchers surmised that early action by authorities may have played a role.  "Measures such as travel restrictions, curfews and school closures were implemented early in Africa compared with other continents, often before an African country had detected a case," they wrote.

The authors attributed this readiness to take early action to the experiences of many African countries with other infectious diseases such as Ebola and Lassa fever. The rapid response most likely led to a slower spread of the infection, they said.

'The measures are working'

"We know that the measures are working," says Edward Chu, emergency medicine adviser at Doctors Without Borders. "However, strict measures are difficult to maintain over a long period of time. We can therefore assume that with further relaxation, the number of infections will also increase."

Nevertheless, according to the authors of the Science article, there must be other reasons why the worst-case scenario has not occurred, because "[m]ost people work in the informal business sector, such as in traditional markets, making strict lockdown measures impossible to implement."

Young continent

Age, for example, could be one reason. On average, the population of the African continent is 19.7 years old — only half as old as people in the US. Although the novel coronavirus also infects the young, it is mainly the elderly who come to hospitals with severe cases of the disease and die from the infection.

The low recorded infection rates could also be related to this low average age on the continent. That is because young people are more often asymptomatic. Because they do not become noticeably ill, they are less likely to be tested and examined, says Chu — especially when the country's health care system is shaky anyway and testing capacity is low.

"The lack of testing capacity makes it extremely difficult to say how much the pandemic will actually affect the populations of African countries," says Chu.

Parasitic boost to immune system?

The analysis published in Science says immune systems influenced by African environments could be another reason for the comparatively mild course of the pandemic. "It is increasingly recognized that the immune system is shaped not only by genetics but also by environmental factors, such as exposure to microorganisms and parasites. This educates the immune system to protect against invading pathogens not only specifically but also nonspecifically," the researchers write.

This could decisively mitigate the severity of an infectious disease and be another reason why the expected high number of victims in Africa has so far failed to materialize.

 The immunologist and parasitologist Achim Hörauf is researching this hypothesis at the University Hospital in Bonn. He is especially interested in worms, which live more or less harmoniously as parasites in the bodies of people in many African countries.

This harmony is possible only because in many cases the worms do not trigger a strong immune response. They avoid it by signaling to the immune system with certain secretions that there is no reason for it to get het up. "It could be that the COVID-19 infection is better tolerated this way," says Hörauf. An excessively violent response from the immune system can lead to severe courses of COVID-19.

While parasites may make a milder course of infection more likely, non-infectious conditions such as cardiovascular illnesses, obesity and type 2 diabetes often cause big problems. And these are typical diseases above all in Western industrialized countries. At least, for now: In the urban regions of African states, these lifestyle diseases have already found their way into the population. 

Collateral damage

But although the expected complete catastrophe has not yet occurred, SARS-CoV-2 has still had devastating consequences for Africa. "The virus indirectly has enormous effects on many people in the African states. The collateral damage caused by the pandemic measures could be much more acute in many countries than the direct damage caused by the virus," says physician Chu. The youngest ones are hit the hardest here, Chu says, adding that food and medication shortages often have fatal consequences for children in particular.

The organization UNAIDS, for example, reported back in May that there were bottlenecks in the supply of antiretroviral drugs, which are essential for the treatment of HIV. The closure of national borders and the temporary suspension of air traffic opened up a supply gap that was exacerbated by the fact that HIV drugs were used to treat COVID-19 patients as well.

UNAIDS and the World Health Organization (WHO) have predicted that this situation could lead to an additional 500,000 AIDS deaths. The aid organization Oxfam warned in July that measures imposed to stem the spread of the pandemic could result in 12,000 starvation deaths per day around the globe by the end of the year.

Six of the 10 "worst hunger hotspots" named by Oxfam are in Africa.