Study explores differences in COVID-19 severity internationally

Sept. 9, 2021

The U.S. Centers for Disease Control and Prevention (CDC) recently awarded a $10 million grant to a team at the University of Florida for a project examining factors influencing COVID-19 severity in sub-Saharan Africa.

The team and its international collaborators will study the current and past history of exposure to the SARS-CoV-2 virus and its genetic variants that cause COVID-19 in two African countries, along with other factors. The project will also use engineered CRISPR-based genetic tests for detecting SARS-CoV-2 and other pathogens.

“It’s fundamentally curious,” said Rhoel Dinglasan, Ph.D., M.P.H., a professor of infectious diseases with the University of Florida College of Veterinary Medicine, part of UF Health, the university’s academic health center. “It seems like COVID-19 is not affecting people in Africa as severely as it has in North America. But why?”

The Democratic Republic of Congo and Nigeria have so far reported fewer infections and deaths due to COVID-19 compared with heavily affected western countries, Dinglasan said. The researchers will coordinate closely with the Africa Centres for Disease Control and Prevention to characterize host and pathogen features that differentiate the pandemic experience of the United States and sub-Saharan countries.

Dinglasan, who is also affiliated with the UF Emerging Pathogens Institute, is well acquainted with human and zoonotic diseases that are endemic to sub-Saharan Africa. His work has primarily focused on vector-borne diseases, such as malaria and arboviruses like West Nile, dengue and Zika.

The idea for the current COVID-19 comparative project was born out of curiosity. Dinglasan couldn’t help but notice that, compared with Florida, severe COVID-19 didn’t appear as widespread at many of the sites in the Democratic Republic of Congo where he conducts malaria research. It could be that these areas have tested fewer people compared with other countries, but Dinglasan suspects this alone does not fully explain the disparity.

“Although lack of testing capacity may explain differences in case numbers, the lower number of severe cases leading to death suggests that other factors may be influencing the local COVID-19 epidemic in each country,” said Dinglasan. “When we remove mitigation strategies such as testing, masking, physical distancing and vaccination, we are left looking at what endemic diseases people in other countries are experiencing as the influencing factors.”

Common parasitic infections found in sub-Saharan Africa, such as malaria and schistosomiasis, can suppress the immune system, which might then prevent severe COVID-19 from developing, he said. A dampened immune response during a SARS-CoV-2 infection can, in turn, prevent the cascade of hyperinflammation that often proves so deadly in COVID-19 patients. Another possibility is that infections with other diseases results in cross-protective immunity.

Dinglasan has several long-term malaria studies ongoing in urban and rural settings in the Democratic Republic of Congo and has connections at a network of clinics and hospitals that will be useful in the new research. Through long-standing personal relationships in Nigeria, the project will leverage existing surveillance networks there, too.

“Nigeria has a system of clinics and hospitals already in place to monitor infectious diseases across urban and rural settings as well,” said Dinglasan. “The ability to mirror surveillance approaches in two countries will help us learn about differences in diverse infectious disease patterns between rural villages and denser urban areas.”

The study results will enable scientists to characterize the different epidemiological presentations of COVID-19 in two populous African countries and relate the data to different public health interventions in Nigeria and the Democratic Republic of Congo, Happi added.

Researchers will collect blood samples from 1,500 participants per country to test for markers of past and current SARS-CoV-2 infection and other endemic parasites or viruses. The samples will be collected four times over several years to track participants’ health and disease risk.

University of Florida Health

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