Background
The damaging medical consequences, as well as the destructive economic and social ripple effects of the COVID-19 pandemic have been well described.1 Individuals’ physical and mental health, behaviour and social security have been impacted.2 As of September 2022, over 6.5 million people have died from the disease.3 Non-pharmacological interventions to control the spread of COVID-19 have included limiting citizens’ movement (‘lockdowns’), emphasising physical distancing, hand sanitising and mask wearing. The most effective non-pharmacological interventions appear to have been lockdowns.4 Counterintuitively, in the context of lockdowns, these interventions often significantly limited individuals’ access to physical activity. There are now excellent data supporting the protective effects of regular physical activity against severe COVID-19 outcomes, such as hospital and intensive care unit admission, ventilation and death.5–8
For pharmacological interventions against COVID-19, vaccination remains a clinically effective and cost-effective modality. Recent studies show vaccine effectiveness against COVID-19-related hospital admissions at between 73% and 94%.9 Healthcare workers across eight locations in the USA who were fully vaccinated (2 weeks after a second dose) with mRNA BNT162b2 (Pfizer-BioNTech) were 90% less likely to be infected than those who were unvaccinated.10 Similar findings were shown with inactivated SARS-CoV-2 vaccines.11 Vaccine effectiveness has been shown across age bands, ethnic groups, and risk categories.12
The emergence of the field of exercise immunology has enhanced understanding of how regular moderate intensity physical activity improves immunosurveillance with many pronounced health benefits.13 These studies have extended to include the effect of physical activity on vaccine effectiveness. The most studied vaccine in the context of chronic physical activity and vaccine effectiveness is the influenza vaccine. Regular high levels of physical activity have been shown to improve immune responses to influenza vaccination, especially in older adults.14 15 A study evaluating the effects of physical activity in women administered the pneumococcal vaccine found no significant difference between women who embarked on a physical lifestyle intervention and those who did not, but acknowledged potential methodological limitations,16 while the effects of physical activity on vaccines administered to younger people have been equivocal.17 Most of these studies have measured antibody responses to determine vaccine efficacy and suggest that regular physical activity of moderate intensity enhances the protective effect of vaccines, especially in those with immune dysfunction, including the elderly.
In a South African patient cohort exposed to the 20 hours/501Y.V2 (‘Beta’) variant, the Ad26.COV2.S vaccine has been shown to be 64% effective against moderate to severe COVID-19 and 81.7% effective against severe to critical disease, 28 days or more after vaccination.18
To our knowledge, no study has assessed the association between measured physical activity and vaccination effectiveness against COVID-19 admission. This study’s findings may inform guidance on physical activity for individuals with reduced immune function, including the elderly and those with comorbidities, cohorts shown to be particularly vulnerable to severe outcomes from COVID-19.