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Living with overweight impedes the body's immune response to SARS-CoV-2

Research led by University of Queensland has revealed that living with overweight can impair the body's antibody response to SARS-CoV-2 infection, but not to the protection offered by vaccination. Led by the University’s School of Chemistry and Molecular Biosciences, their PhD candidate, Marcus Tong, said the findings built on the team's existing research on how COVID-19 affects people who are overweight.

"We've previously shown that being overweight, not just being obese, increases the severity of SARS-CoV-2," eplained Tong. "But this work shows that being overweight creates an impaired antibody response to SARS-CoV-2 infection but not to vaccination."

For their research, the team collected blood samples from people who had recovered from COVID-19 and not been reinfected during the study period, approximately three months and 13 months post-infection. They also collected blood samples from people approximately five months of post-second dose COVID-19 vaccination (the majority of whom did not have a prior SARS-CoV-2 infection). They measured their humoral responses to SARS-CoV-2, grouping individuals based on a BMI greater or less than 25kg m2.

"At three months post-infection, an elevated BMI was associated with reduced antibody levels," he said. "And at 13 months post-infection, an elevated BMI was associated with both reduced antibody activity and a reduced percentage of the relevant B cells, a type of cell that helps build these COVID-fighting antibodies."

In contrast, an elevated BMI had no effect on the antibody response to COVID-19 vaccination at approximately six months after the second vaccine was administered.

"If infection is associated with an increased risk of severe disease and an impaired immune response for the overweight, this group has a potentially increased risk of reinfection," added Associate Professor, Kirsty Short. “It makes it more important than ever for this group to ensure they're vaccinated."

Short explained that from a public health perspective, this data draws into question policies around boosters and lockdowns: "We'd suggest that more personalised recommendations are needed for overweight people, both for ongoing COVID-19 management and future pandemics. Finally, the data provides an added impetus to improve SARS-CoV-2 vaccination in low-income countries, where there's a high percentage of people who are overweight and are dependent on infection-induced immunity."

The findings were reported in the paper, ‘Elevated BMI reduces the humoral response to SARS-CoV-2 infection’, published in Clinical & Translational Immunology. To access this paper, please click here


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