Sunday, June 26

Trying to solve a Covid mystery: Africa’s low death rates

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KAMAKWIE, Sierra Leone — There are no Covid fears here.

The district’s Covid-19 response center has registered just 11 cases since the start of the pandemic, and no deaths. At the regional hospital, the wards are packed — with malaria patients. The door to the Covid isolation ward is bolted shut and overgrown with weeds. People cram together for weddings, soccer matches, concerts, with no masks in sight.

Sierra Leone, a nation of eight million on the coast of Western Africa, feels like a land inexplicably spared as a plague passed overhead. What has happened — or hasn’t happened — here and in much of sub-Saharan Africa is a great mystery of the pandemic.

The low rate of coronavirus infections, hospitalizations and deaths in West and Central Africa is the focus of a debate that has divided scientists on the continent and beyond. Have the sick or dead simply not been counted? If Covid has in fact done less damage here, why is that? If it has been just as vicious, how have we missed it?

The answers “are relevant not just to us, but have implications for the greater public good,” said Austin Demby, Sierra Leone’s health minister, in an interview in Freetown, the capital.

The assertion that Covid isn’t as big a threat in Africa has sparked debate about whether the African Union’s push to vaccinate 70 percent of Africans against the virus this year is the best use of health care resources, given that the devastation from other pathogens, such as malaria, appears to be much higher.

In the first months of the pandemic, there was fear that Covid might eviscerate Africa, tearing through countries with health systems as weak as Sierra Leone’s, where there are just three doctors for every 100,000 people, according to the World Health Organization. The high prevalence of malaria, H.I.V., tuberculosis and malnutrition was seen as kindling for disaster.

That has not happened. The first iteration of the virus that raced around the world had comparatively minimal impact here. The Beta variant ravaged South Africa, as did Delta and Omicron, yet much of the rest of the continent did not record similar death tolls.

Studies that tested blood samples for antibodies to SARS-CoV-2, the official name for the virus that causes Covid, show that about two-thirds of the population in most sub-Saharan countries do indeed have those antibodies. Since only 14 percent of the population has received any kind of Covid vaccination, the antibodies are overwhelmingly from infection.

A new W.H.O.-led analysis, not yet peer-reviewed, synthesized surveys from across the continent and found that 65 percent of Africans had been infected by the third quarter of 2021, higher than the rate in many parts of the world. Just 4 percent of Africans had been vaccinated when these data were gathered.

So the virus is in Africa. Is it killing fewer people?

Some speculation has focused on the relative youth of Africans. Their median age is 19 years, compared with 43 in Europe and 38 in the United States. Nearly two-thirds of the population in sub-Saharan Africa is under 25, and only 3 percent is 65 or older. That means far fewer people, comparatively, have lived long enough to develop the health issues (cardiovascular disease, diabetes, chronic respiratory disease and cancer) that can sharply increase the risk of severe disease and death from Covid. Young people infected by the coronavirus are often asymptomatic, which could account for the low number of reported cases.

Plenty of other hypotheses have been floated. High temperatures and the fact that much of life is spent outdoors could be preventing spread. Or the low population density in many areas, or limited public transportation infrastructure. Perhaps exposure to other pathogens, including coronaviruses and deadly infections such as Lassa fever and Ebola, has somehow offered protection.

Since Covid tore through South and Southeast Asia last year, it has become harder to accept these theories. After all, the population of India is young, too (with a median age of 28), and temperatures in the country are also relatively high. But researchers have found that the Delta variant caused millions of deaths in India, far more than the 400,000 officially reported. And rates of infection with malaria and other coronaviruses are high in places, including India, that have also seen high Covid fatality rates.

So are Covid deaths in Africa simply not counted?

Most global Covid trackers register no cases in Sierra Leone because testing for the virus here is effectively nonexistent. With no testing, there are no cases to report. A research project at Njala University in Sierra Leone has found that 78 percent of people have antibodies for this coronavirus. Yet Sierra Leone has reported only 125 Covid deaths since the start of the pandemic.

Most people die in their homes, not in hospitals, either because they can’t reach a medical facility or because their families take them home to die. Many deaths are never registered with civil authorities.

This pattern is common across sub-Saharan Africa. A recent survey by the United Nations Economic Commission for Africa found that official registration systems captured only one in three deaths

The one sub-Saharan country where almost every death is counted is South Africa. And it’s clear from the data that Covid has killed a great many people in that country, far more than the reported virus deaths. Excess mortality data show that between May 2020 and September 2021, some 250,000 more people died from natural causes than was predicted for that time period, based on the pattern in previous years. Surges in death rates match those in Covid cases, suggesting the virus was the culprit.

Dr. Lawrence Mwananyanda, a Boston University epidemiologist and special adviser to the president of Zambia, said he had no doubt that the impact in Zambia had been just as severe as in South Africa, but that Zambian deaths simply had not been captured by a much weaker registration system. Zambia, a country of more than 18 million people, has reported 4,000 Covid-19 deaths.

“If that is happening in South Africa, why should it be different here?” he said. In fact, he added, South Africa has a much stronger health system, which ought to mean a lower death rate, rather than a higher one.

A research team he led found that during Zambia’s Delta wave, 87 percent of bodies in hospital morgues were infected with Covid. “The morgue was full. Nothing else is different — what is different is that we just have very poor data.”

The Economist, which has been tracking excess deaths throughout the pandemic, shows similar rates of death across Africa. Sondre Solstad, who runs the Africa model, said that there had been between one million and 2.9 million excess deaths on the continent during the pandemic.

“It would be beautiful if Africans were spared, but they aren’t,” he said.

But many scientists tracking the pandemic on the ground disagree. It’s not possible that hundreds of thousands or even millions of Covid deaths could have gone unnoticed, they say.

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