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Regular physical activity may boost effectiveness of Covid-19 jab

- Wits University

A new study by a team of South African researchers shows the more you exercise, the more protective Covid vaccination seems to be.

Regular physical activity may boost the effectiveness of the Covid-19 jab, with the level of protection afforded against serious infection rising in tandem with the amount of physical activity done, suggests research published online in the British Journal of Sports Medicine.

The research done by team of South African scientists, including from Wits Sport and Health (WiSH), a Research Group at Wits University in Johannesburg, South Africa, shows convincing evidence that regular physical activity helps ward off the consequences of serious Covid-19 infection, reducing the risk of hospital admission, intensive care, assisted ventilation or death. Similarly, vaccination also minimises these risks.

Previously published research, also by WiSH using Discovery Health data, on the additive effects of physical activity on vaccination against various infections, suggests that it enhances the body’s immune response. Up until the recent study, it was not known whether this might also apply to SARS-CoV-2, the virus responsible for Covid-19 infection.

For the study, researchers drew on anonymised Discovery Health medical records and wearable activity tracker data for healthcare workers belonging to a medical insurance scheme as well as a health promotion and behavioural change programme. 

Participants were mapped to physical activity categories using their average monthly levels in the two years preceding the start of the study: under 60 minutes of a week (low); at least 60-149 minutes (medium); and 150 minutes + (high).

Covid-19 swab test results were analysed for 53,771 participants with low levels of physical activity, 62,721 with medium levels, and 79,952 with high levels. 

Complete health, Covid-19 vaccination and physical activity data were obtained for 196,444 adults who tested negative for SARS-CoV-2. The study participants were vaccinated between mid-February to the end of October 2021 with a single dose of the Johnson & Johnson vaccine.

Vaccine effectiveness against Covid-19 among fully vaccinated people in the low physical activity category was 60%. In other words, the risk of hospital admission was reduced by 60% in this group.  

Comparable risk reductions for those in the medium and high physical activity groups were, respectively, 72% and 86%. 

“Those who were fully vaccinated and who clocked up high weekly levels of physical activity were nearly three times less likely to be admitted to hospital than those who were vaccinated but in the low physical activity category,” says Professor Jon Patricios from Wits Sports and Health.

Similarly, those in the medium physical activity category were nearly 1.5 times less likely to be admitted to hospital with Covid-19 infection.

“The findings suggest a possible dose–response where high levels of physical activity were associated with higher vaccine effectiveness,” says Patricios. 

“This substantiates the WHO recommendations for regular physical activity — namely, that 150–300 minutes of moderate intensity physical activity per week has meaningful health benefits in preventing severe disease, in this context against a communicable viral infection.”

As this is an observational study, the researchers were not able to establish the reason for the increased effectiveness of the vaccine. However, it is suggested that it may be because of a combination of enhanced antibody levels, improved T cell immunosurveillance, and psychosocial factors.

The researchers also warn that the results cannot be generalised to other populations, virus variants, or other types of Covid-19 vaccines.

“The protective effect of physical activity appears to result from exercise’s powerful effect at many levels of the body’s physiology that impact almost every organ system including the immune system,” says Patricios.

“Public health messaging should encourage physical activity as a simple, cost-effective way of enhancing vaccine effectiveness to mitigate the risk of severe Covid-19 illness requiring hospital admission.”

The Wits Institute for Sports and Health received a boost earlier this year when the family of Brian and Dorothy Zylstra pledged R80 million towards the Institute in their name. This donation from the Skye Foundation was announced at the launch of the Friends of Wits in Australia in May as part of the centenary campaign.