What can we learn from the course of COVID-19 in Africa?7 August 2020• PRESSRELEASE
On August 7, the WHO reports more than 1 million recorded COVID-19 infections in Africa and calls it a turning point. Yet, the number of people who are sick or deceased on the continent is relatively low. How is that possible? In an article in Science, LUMC researchers and partners in Africa highlight the possible causes and add the hypothesis that the distinct wiring of the immune system might also be playing a role in the relatively low COVID-19 death rates in Africa.
According to the authors, many predicted a very dark scenario for Africa with millions of COVID-19 deaths as many countries on the continent grapple with poverty, poor health systems and unhygienic conditions. However, factors such as country lockdowns, bans on mass gatherings, young population age, and less diabetes and cardiovascular diseases probably contributed to the dampened COVID-19 death rates so far.
Intense exposure to microorganisms
LUMC LEaDing fellow Simon Jochems and Professor of Parasitology Maria Yazdanbakhsh, with their co-authors, write in Science that the more intense exposure to microorganisms and parasites might also play an important role in the reported low death rate per capita in Africa compared to many other parts of the world. This exposure leads to a distinct wiring of the immune system. Yazdanbakhsh: “We have shown together with our partners in low to middle income countries that the immune system of people living in less urban areas is very distinct. This is not just because of genetics, but more importantly due to environmental factors. Of note, the largest burden of disease of COVID-19 in Africa is found in South-Africa, the most developed country on the continent, accounting for over 50% of cases.”
Previous research has shown that the immune system of someone living in the Netherlands is very distinct from a person with the same age and sex living in Senegal, Gabon or Indonesia. But more importantly, someone living in an urban area of these countries has even a more distinct immune system than a genetically similar person living in a rural area of the same country. “A distinct immune system will also mean a distinct response to SARS-CoV-2. For example, one of the immune cells in the lungs that leads to the cytokine storm, might be better regulated in Africans and therefore cause less havoc upon infection with SARS-CoV-2”, explains Jochems, an expert in mucosal immunology and in particular of the airways.
Africa in COVID-19 research roadmap
Therefore, Africa should be included in the COVID-19 research roadmap, states Yazdanbakhsh. “Understanding the variability in the epidemiology of COVID-19 and identifying the key factors that contribute to the course of the pandemic, can help us develop innovative policies, therapies and vaccines that help the global fight against this and possibly future pandemics.”
“What is contributing most strongly to the pattern of COVID-19: social distancing, ban on large gatherings, socioeconomic segregation, or washing hands? Why is young age protective? Which cells or signals in the immune system need to be triggered to prevent the excessive inflammation? The answers to all these questions, through multisectoral research, would provide us with the knowledge that we need to stop the pandemic."
LUMC Global programme
The long term and sustained relations between LUMC and African research partners has been essential in being able to publish these insights. Yazdanbakhsh: “In order to understand global health issues, looking at and working closely together with researchers in continents such as Africa is indispensable.” This is the reason why the LUMC will put extra effort in its international outreach through the LUMC Global programme.
For more information, please read the paper 'COVID-19 in Africa: dampening the storm?' in Science.
Photo: Diagnosis of COVID-19 in the laboratory in CERMEL, Gabon. Curtsy of Professor Ayloa Akim Adegnika.