The true coronavirus tax in sub-Saharan Africa may be masked by the enormous variability of risk and control factors

One of the early features of reporting on a coronavirus pandemic was the perception that sub-Saharan Africa was largely spared the growing infection and mortality rates that disrupted countries around the world.

Although a seemingly mild, real tribute to the new coronavirus, SARS-CoV-2, in sub-Saharan Africa may be masked by the tremendous variability of risk factors combined with surveillance challenges, according to a paper published in the journal Nature Medicine by an international team led by Princeton University researchers.

“Although reports of SARS-CoV-2 billing in sub-Saharan Africa to date have been generally low compared to other regions, we must take into account the extreme national and subnational variability of pandemic drivers in this region,” said first author Benjamin Rice, presidential postdoctoral fellow. a researcher in ecology and evolutionary biology at Princeton.

Accurate projections for sub-Saharan African countries remain difficult given the lack of information on the prevalence of risk factors such as chronic diseases and access to health care, Rice said. But he and his co-authors synthesized a wide range of information on risk factors and infection trends for sub-Saharan Africa from February 25 to December 20, 2020.

The researchers then developed an interactive network tool that shows the impact that various risk factors – such as chronic disease rates, local population density and the percentage of urban population living in overcrowded apartments – could have on the trajectory of pandemics.

Researchers have developed an interactive online tool to estimate the rate of severe coronavirus infections per country based on the influence of various risk factors. Any two risk factors can be selected at once from the left toolbar. As an example, the multicolored map shown above shows the relative risk in each country of diabetes prevalence (horizontal line) ranging from lowest (white) to highest (pink) and the number of hospital beds per 100,000 people (vertical line) ranging from most (white). ) to at least (green). The color of the square where these two values ​​meet indicates a risk of severe COVID-19 infection in the country, from low (white) to very high (dark blue). The above tabs show additional interactive actions. Access the full-size tool. Interactive map of Malawi Rajeev, Marjolein Bruijning and Ian Miller, Department of Ecology and Evolutionary Biology

Researchers have also developed a series of simulations to assess the role of different drivers of viral spread. Their results showed that climatic differences between the population centers of sub-Saharan Africa have little effect on early outbreak trajectories.

This finding is consistent with research by Rice’s co-authors Rachel Baker, a research associate with Princeton’s High Meadows Institute of Environment (HMEI), and C. Jessica Metcalf, associate professor of ecology and evolutionary biology and public affairs at Princeton and an associate of HMEI. published suggesting that climatic conditions in summer and winter would have minimal effect on the coronavirus during the pandemic phase. Baker, Metcalf, and many authors of the current study are linked to the HMEI initiative on climate change and infectious diseases.

The Nature Medicine article also found that differences in connectivity, although rarely taken into account, are likely to contribute to differences in the way the virus has spread in sub-Saharan Africa, said co-author Fidisoa Rasambainarivo, a Madagascar-based postdoctoral research associate at HMEI.

“These results could allow officials to predict what might happen in their countries given the different contexts of human movement and health networks across sub-Saharan Africa,” Rasambainarivo said.

The researchers developed national and subnational analyzes that indicated specific environments in which strengthening coronavirus surveillance could bring the greatest return, Metcalf said. An urgent focus in sub-Saharan Africa is developing a better understanding of the intersection between the pace of the epidemic and the likelihood of disruptions to local and national health systems, which are already fragile in many areas.

These results underscore the importance of development tools such as serology to better measure sensitivity in order to directly assess the current situation and landscape of risk, ”Metcalf said.

Additional authors from Princeton in this paper include postdoctoral researcher Marjolein Bruijning et al. candidates Malavika Rajeev and Ian Miller, all in the Department of Ecology and Evolutionary Biology.

Authors from the University of Antananarivo and the University of Fianarantso in Madagascar, Johns Hopkins University School of Medicine, were also in the paper. University of Southampton, Research Institute for Development and University of Paris, Stellenbosch University of South Africa and the University of Wisconsin-Madison.

The paper “Variation of SARS-CoV-2 outbreaks across sub-Saharan Africa” ​​has been published online Feb. 2, Nature Medicine. This work was supported by the Cooperative Institute for Ground Modeling (CIMES), the High Meadows Institute for Environmental Protection (HMEI), and the Princeton Institute for International and Regional Studies (PIIRS).

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