Benin COVID-19: “No scientifically proven data today allows preventive treatment with antimalarials,” according to Professor Thierry Adoukonou
In the first edition of “Questions for the Experts,” an initiative of the African School of Economics, Professor Thierry ADOUKONOU, Director of the Public Health and Epidemiology School (ENATSE) at the University of Parakou explains the low COVID-19 contamination rate in Africa. He also points out the position of scientists with regard to the effectiveness of antimalarial therapies.
ASE: Professor Adoukonou, how do we explain the low contamination rate of COVID-19 in Africa as opposed to the WHO estimates?
Prof. Adoukonou: Since its outbreak in China in the district of Hubei in December 2019, the new coronavirus infection has gradually spread around the world. First in Asia then in Europe and America and in Africa since February. However, the epidemiological indicators are not the same everywhere. It should be remembered that the spread of an infection by the contagious pathogenic agent in a population is strongly linked to the factor R0, which is well known in epidemiology. This number is nothing but the number of people who are potentially subjected to being contaminated by someone who was once infected. Indeed, the virus’ spread rate depends not only on factors related to the virus but also on the host and the ecosystem (environment). To specifically answer the question, we were expecting an exponential increase in cases in Africa given the precarious living conditions and health system in this region of the globe. Africa has more than a billion people, almost 3 to 4 times the population of the United States (USA), but has fewer cases than the United States. Furthermore, the total number of deaths on May 16, 2020 in Africa (around 2,630) is very far from the more than 88,000 deaths recorded in the USA. The low screening rate cannot solely explain this because, by relating the number of positive cases to the number of subjects screened or to the population, Africa still seems relatively unaffected. Several reasons could explain:
- The African population is relatively younger (more than 70% of the population is under 30 years old) compared to Westerners, but very large serological surveys in the general population would allow these data to be better specified;
- The disease affects older people more severely;
- Possible effect of the climate (not yet formally demonstrated). At this level, we note a strong disparity even within Africa. Intertropical Africa seems more spared than the Maghreb and South Africa, with milder climates;
- Possible awareness of antimalarials (this region of the world has more than 90% of malaria cases). Antimalarials having shown an effect on the virus in vitro;
- Comorbidities (diabetes, cardiovascular disease, etc.) are less frequent, the population being relatively young;
- A possible genetic susceptibility;
- The delay in the onset of infection in this region (being better prepared and aware of the infection);
These assumptions should be confirmed by epidemiological and ecological studies.
ASE: Do malaria treatments have a preventive effect on COVID19?
Prof. Adoukonou: Chloroquine and hydroxychloroquine have an effect on membrane viruses. In fact, chloroquine in vitro inhibits viral replication by blocking the acidification of the pH and also acts on the cascade of inflammatory reactions (cytokine storm). These effects are almost the same with other antimalarials. This is proven in vitro on several viruses (e.g. Dengue, Chikungunya, and SARS-Cov-1). But all the clinical trials carried out in these infections are negative or even harmful. Currently validated scientific data do not argue in favor of the effectiveness of chloroquine and its derivatives on COVID-19 but its ineffectiveness is not clearly proven. Although observational studies seem to show a reduction in viral load, it is unclear whether this is the natural history of the disease or a real effect of the treatment. No large-scale clinical trial has shown the efficacy of chloroquine or any antimalarial in the treatment of COVID-19.
This requires great caution, especially since this treatment is not devoid of cardiac and visual side effects. On the preventive level, it is not scientifically justified to speak of chemoprophylaxis. No study today has shown that taking any antimalarials will protect against the disease. In science we need proof with recognized standards. We must not fall into dogmatism. Nor should we, under the pretext of any urgency, do anything and flout the essential ethical rules which are the principle of beneficence, non-maleficence and freedom. Remember that in more than 80% of the cases the infection is asymptomatic and that only less than 5% of infected people will present complications requiring resuscitation. The rate of side effects is not insignificant with these drugs. Furthermore, attention should be drawn to the misuse of these drugs which could induce resistance. We should not forget that WHO draws attention to the hazards related to their untimely use and that Africa could face the emergence of resistance, especially for malaria.
In conclusion, no scientifically proven data today authorizes preventive treatment with antimalarials.
