Africa out of Corona

But what's happening in Africa? To answer this question, a serological test adapted to the African context is currently being deployed in six countries. The aim is to gain a better understanding of the spread of the virus on a continent apparently less affected than the West by coronavirus-related mortality, and thus limit the deleterious effects of an ill-adapted response.

In Africa, the Covid-19 epidemic began two or three weeks after the one that hit Europe. " We could have feared the worst, but with the exception of a few countries such as South Africa, we didn't see the tsunami of serious hospitalizations and fatal forms observed in the West," reports Eric Delaporte, researcher at the TransVIHMI* laboratory and infectious disease specialist at Montpellier University Hospital. How can this difference be explained? This is the challenge of the ARIACOV project led by TransVIHMI and piloted by this physician accustomed to the African field, where he has notably monitored the AIDS and Ebola epidemics.

Testing for coronaviruses in general

There are many possible explanations for the lower mortality rate from Covid in Africa, not least demographics and the youthfulness of the population, which is inevitably less affected by severe forms of the disease. Other factors, notably environmental, may come into play but, as Eric Delaporte points out, "given the low diagnostic capacity in these countries, the first question is to know whether or not the virus is spreading, and to what extent it is spreading in the population, in order to assess the dynamics of the epidemic", explains the coordinator of the COVID Sud Task Force (ANRS, REACTing/Inserm, IRD).

To answer this first question, a major epidemiological survey was launched in six partner countries: Senegal, Ghana, Guinea, Cameroon, Benin and the Democratic Republic of Congo. To carry out these screening campaigns, a serological test specifically adapted to the African context was developed. What makes it special? It contains markers for different coronaviruses, not just SARS-CoV-2. " The aim is to be able to differentiate between people who have been affected by SARS or MERS, but also to add markers for winter coronaviruses and coronaviruses present in African fauna [read the article "Bats under the radar "]", explains the researcher.

Why look for contamination by coronaviruses, which may be present in wildlife but have never caused illness in humans ? Because humans may well have encountered these coronaviruses without having developed any illness or symptoms, but having developed antibodies". This encounter could be at the origin of a cross-immunity phenomenon, and thus explain the low spread of the virus, thanks to a kind of semi-protection. " It's only a hypothesis, but it needs to be studied," says Eric Delaporte.

Adapting the response to the actual epidemic

Several surveys will be carried out in different countries, each involving a minimum sample of 1,500 people, and repeated every two months if possible, in order to assess the dynamics of the epidemic. This essential assessment is combined with a sociological analysis of the impact of the epidemic and containment on healthcare systems and societies in general. In Africa, even more than in the West, the side-effects of these protective measures can be more serious than the virus itself.

"In Africa today, fewer people are vaccinated, and access to antiretroviral and tuberculosis treatments is more complicated," explains Eric Delaporte. This is due not only to the fear of being contaminated when visiting health centers, but also to the closure of borders and flight restrictions linked to confinement. "Most of the drugs are generics manufactured in India. Stock-outs are to be feared, and theWHO has estimated that a disruption in access to antiretrovirals lasting more than six months would result in several hundred thousand more AIDS deaths," warns the doctor. Not to mention the consequences of confinement on access to food in countries where a significant proportion of the population lives from day to day.

TransVIHMI 's scientists are already encountering a number of obstacles when it comes to sending the reagents needed for serological testing to Africa. This is due to the pre-emption of batches by Western supplier countries, faced with managing their own emergencies. This is a new situation for Eric Delaporte: "The Covid epidemic is global, unlike those we usually see in Africa. We have to make sure that the emergency in Northern countries is not managed to the detriment of Africa, which could then take second place to the rest of the world".

* UMR TransVIHMI (UM, IRD, INSERM U1175, Université Check Anta Diop (Dakar, Senegal), Université Yaoundé 1 (Cameroon))