The Evolution of COVID-19 in Africa

While Africa was the subject of concern, the Covid-19 epidemic does not seem to be igniting at the moment. How to explain this situation?

Éric D’Ortenzio is a medical doctor and public health specialist. He is the scientific coordinator of  REACTing (a multi-disciplinary consortium that has been created by a French public research organization under the name of Inserm and that is dedicated to Immunology, Inflammation, Infectiology, and Microbiology) ‘. The former returns for the conversation on a Frensh Journal  on the evolution of the COVID-19 epidemic on the African continent.

In Africa , where is the situation of the epidemic?

The explosion of the Covid-19 epidemic that was feared a few weeks ago has not yet occurred. Official contamination figures are still relatively low: as of June 4th, the  CDC Africa  recorded 162,673 cases and 4,601 deaths on the continent. But some states are more or less affected: talking about Africa in general does not make sense, it is a continent made up of 54 countries and populated by 1.2 billion inhabitants, whose realities are very different depending on the regions.

The Maghreb countries were the first to be affected, notably Egypt , which is one of the first countries to report imported cases, Algeria , Morocco . This age of the epidemic could explain why there are the most cases, reported to the population.

In sub-Saharan Africa, health systems are more or less fragile depending on the country. This would partly explain the disparities in the dynamics of the epidemic: some governments have been able to put in place an important number of tests, others have acquired after years and years of experience in epidemics which they apply during the current crisis.

Countries that can better test their populations are likely to be better able to control the Covid-19 epidemic by isolating the sick and identifying contacts. We can clearly see that the situation differs from place to place: the number of Covid-19 cases, for example, has increased much more in Ivory Coast and Senegal than in Burkina or Mali. What we see, however, represents only the tip of the iceberg, based on the official figures in circulation.

How to explain this weak growth of the epidemic, contrary to the fears expressed at the beginning of the crisis?

Several hypotheses are considered to explain it. The available test offer must have played a role: due to international tension on equipment and reagents, supply difficulties were significant. This would have resulted in insufficient access to tests, and therefore an underestimation of the number of cases. But this does not explain everything.

A second hypothesis is also advanced: the population is on average rather young on the continent, and the proportion of people over 65 is very low (perhaps 5% of the population in sub-Saharan Africa). This could explain this impression that the epidemic is not flaring: the virus would circulate, but the little or asymptomatic forms, not detected, would be in the majority. We know that severe forms mainly concern the elderly or at risk, with comorbidities such as obesity, diabetes, cardiovascular problems. However, even if in Africa we consider that there is an epidemiological transition (from infectious diseases to chronic diseases) and that more and more people develop diabetes, overweight, and cardiovascular pathologies, the prevalence remains lower than that from European or North American countries.

Another hypothesis: the first cases would have rather affected the socio-economic elite, that is to say people who can afford to travel abroad. When they got home, they imported the disease. These first cases, which belonged to the wealthy social classes, could perhaps have been better isolated and tested by the first days following their return. Furthermore, at that time, the governments, worried about the European situation, were starting to put in place containment measures. The conjunction of these two factors would partly explain why the disease has not spread massively in the general population.

Explanations are also to be sought on the side of lifestyles, which differ from those of Western countries. Due to often precarious living conditions, a large part of the population lives more outside. People spend less time in confined and confined spaces where the virus is known to be better transmitted. This also contributes to the dynamics of the epidemic.

Among the avenues to explore is also the immune response: there could be differences in certain populations subjected to numerous microbial exposures. We can hypothesize a cross immunity (the antibodies produced following a previous infection by other pathogenic microbes would also be active, at least partially, against the coronavirus Sars-CoV-2, Editor’s note).

Finally, it would also be necessary to study the question of climate, to determine for example if heat, humidity could play a role.

This bundle of hypotheses would explain why the epidemic does not seem to be igniting in Africa. However, to confirm these assumptions, studies to better understand what happened in each country, at the scale of a region, a city, will be necessary. Only solid, well-analyzed data can explain what happened. 

In this regard, how does the Covid-19 pandemic affect other epidemics?

In the Democratic Republic of the Congo, there has been a resurgence of Ebola virus disease in North Kivu. We thought the epidemic was over, but a few sporadic cases still occur every week in this region  where armed groups clash . These new cases show that the Ebola epidemic is not under control there. A new outbreak in Equateur province , near the town of Mbandaka, has also just been confirmed.

This situation puts the country in difficulty, especially in the face of other epidemics such as that of measles, very deadly since 2019, which also affects the neighboring Central African Republic. The concomitance of other epidemics such as Lassa fever or yellow fever in Nigeria, Rift Valley fever in Sudan, or cholera epidemics in many countries makes the management of these co-circulations of pathogens more complex. This type of situation concerns various other vulnerable areas elsewhere on the continent.

In addition, the issue of access to the diagnosis of Covid-19 disease in rural areas is often complicated. The offer is centralized in the capitals. Several centers take samples there, which are then sent to the reference laboratories where the analyzes are carried out. When a suspect case is identified in the region, its samples can be sent to the capital, but sometimes the patient moves there. If it is indeed positive, it risks spreading the virus.

What is up next for Africa?

the situation remains very fragile, and it is still too early to know how it will develop. The virus will likely still circulate for several months or even years. From an epidemic, the situation will become endemic.

Co-circulation with other infectious diseases (HIV, malaria, tuberculosis, respiratory infections, diarrhea, etc.) is sometimes compounded by increased vulnerability due to malnutrition. This could be problematic in the case of the Covid-19 epidemic. All the more so since it risks disrupting vaccination programs, making populations even more fragile in the face of vaccine-preventable diseases. Programs to fight other pandemics will also be affected.

Vigilance is therefore required. We must not relax, whether in terms of surveillance, testing offer, clinical management, knowledge of the disease in African contexts. The contribution of the human and social sciences is essential here to better understand and propose relevant prevention measures. The determining factor will be the health system. The countries where it is most fragile will be the most at risk, this is where we must strengthen. All the more, obviously, if the political or health situation is difficult: conflicts, population movements, other epidemics …

All this will play. The concern concerns many countries, in particular those with tens of millions of inhabitants, where the population is sometimes concentrated in overcrowded capitals like Lagos, Cairo, Kinshasa, Johannesburg, Nairobi … If the epidemic soared, it would be very problematic.

The attention paid to the circulation of the virus must remain permanent, to prevent this region of the world from suffering the catastrophe announced which could be in a shape of a large second wave of the Covid-19.

‘ https://www.inserm.fr/en/about-inserm

Written by : Moad Mekroum.