Why has Covid-19 largely spared Africa?

A new study led by the World Health Organization (WHO) has found that, by the third quarter of 2021 – thus, before the emergence of the highly contagious Omicron variant in South Africa in November – 65 percent of the African population already had antibodies against SARS-CoV-2. Since at the time when this data was gathered only four percent of the population of the continent has been vaccinated (to date, this number has increased to 14 percent), the vast majority of these antibodies appear to be the result of natural infection. 

But why have hospitalizations and deaths remained so low in West and Central Africa throughout the pandemic? According to Sierra Leone’s health minister Austin Demby, the answers to this question “are relevant not just to us, but have implications for the greater public good.”

Some scientists argue that perhaps Covid-related hospitalizations and deaths are simply not counted in Africa and that, in fact, the pandemic’s toll has been as great on this continent as in many other parts of the world. Indeed, excess mortality data in South Africa shows that during the first two years of the pandemic, over 250,000 more people died than expected from mortality patterns in previous years. Could it be that in other countries there are similar death rates and they are not noticed and reported?

“We have not seen massive burials in Africa. If that had happened, we’d have seen it,” said Dr. Thierno Baldé, the leader of WHO’s Covid emergency response in Africa. “A death in Africa never goes unrecorded, as much as we are poor at record-keeping,” added Dr. Abdhalah Ziraba, an epidemiologist at the African Population and Health Research Center in Nairobi, Kenya. 

“There is a funeral, an announcement: A burial is never done within a week because it is a big event. For someone sitting in New York hypothesizing that they were unrecorded – well, we may not have the accurate numbers, but the perception is palpable. In the media, in your social circle, you know if there are deaths.”

Sierra Leone’s health minister – a trained epidemiologist – strongly agrees: “We haven’t had overflowing hospitals. We haven’t. There is no evidence that excess deaths are occurring.” 

Some scholars argue that high temperatures, the fact that much of daily life is spent outside, the low population density in many areas, and the relatively young population could have been crucial factors that helped spare the Africans from the worst Covid outcomes. However, India has largely similar conditions, and it nearly collapsed under the Delta variant last spring, with over four million estimated deaths.

Perhaps a more plausible explanation would be that many Africans had cross-immunity from being exposed to a variety of other pathogens, including not only other coronaviruses, but also microbes causing deadlier infections such as malaria, Lassa fever, or Ebola. However, this remains an unproven hypothesis in need of investigation. Urgent research is needed to find out if and which of these pathogens might offer cross-protection against SARS-CoV-2. Clarifying this issue is critical not only for solving Africa’s mysterious relation to Covid-19, but also for the future development of better vaccines and treatments worldwide. 

A pre-print version of the WHO seroprevalence study can be found here.

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By Andrei Ionescu, Earth.com Staff Writer