Regular exercise may enhance the efficacy of Covid-19 vaccines, with protection against severe disease rising hand in hand with increased activity, according to research among members of Discovery Health’s incentive programme, Vitality.
Discovery Health is the medical scheme administrator subsidiary of JSE-listed health and life insurer Discovery, and its Vitality scheme rewards members who exercise regularly with incentives such as discounts on shopping and travel.
The vaccinated participants were healthcare workers who received a single dose of Johnson & Johnson’s Covid-19 shot between February and October 2021, under the Sisonke study run by the Medical Research Council (MRC).
Previous research that showed an association between regular exercise and greater protection from Covid-19 vaccination has relied on people self-reporting their activity levels, and measured blood antibody levels to gauge the effectiveness of the jabs. This study has gone a step further by drawing on data captured by Vitality members’ wearable devices and Discovery Health’s statistics on Covid-19 and hospital admissions, drawn from its client medical schemes.
Researchers measured vaccine effectiveness by avoidance of hospital admission, and compared vaccinated and unvaccinated individuals in three physical activity categories.
Participants were stratified based on their average monthly activity levels in the two years preceding the start of the study: low activity was defined as less than an hour of moderately intense exercise a week, medium activity between an hour and three hours, and high activity as more than three hours. Moderately intense activity was defined as having an average heart rate of between 70 and 79% of maximum heart rate.
The risk of hospital admission among vaccinated healthcare workers was reduced by 60% in the group who engaged in low levels of physical activity, and by 72% and 86% in the medium and high physical activity groups, respectively.
“There isn’t a more powerful non-pharmaceutical intervention than exercise,” said study co-author Jon Patricios, a researcher at Wits Sports and Health. “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,” he said.
Discovery Health chief healthcare analytics actuary Shirley Collie said the study added to a growing body of evidence showing regular exercise boosts the effectiveness of vaccines.
“Ours is not the first study of this nature. Past studies that have measured antibody responses to determine vaccine efficacy [looking at vaccines like the flu vaccine] suggest that regular physical activity of moderate intensity enhances the protective effect of vaccines, especially in those with immune dysfunction including the elderly,” she said.
MRC president Glenda Gray said more research was needed to understand why exercise enhances the protective effects of vaccination. “It may be a combination of enhanced antibody levels, improved T-cell [response] and psychosocial factors,” she said.
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