Long-term air pollution exposure and risk of SARS-CoV-2 infection: A UK-wide cohort study

Background: The association between air quality and risk of SARS-CoV-2 infection is poorly understood. We investigated this association using serological individual-level data adjusting for a wide range of confounders, in a large population-based cohort (COVIDENCE UK).

Methods: We assessed the associations between long-term (2015-19) nitrogen dioxide (NO₂) and fine particulate matter with an aerodynamic diameter of ≤2.5 μm (PM_2.5), exposures with SARS-CoV-2 infection, level of antibody response among those infected, and COVID-19 disease severity. We used serological data from 10,489 participants in the COVIDENCE UK cohort, and estimated annual average air pollution exposure at each participant's home postcode.

Results: After controlling for potential confounders, we found a positive association between 5-year NO₂ and PM_2.5 exposures and the risk of seropositivity: 10 unit increase in NO₂ (μg/m³) was associated with an increasing risk of seropositivity by 1.092 (95% CI 1.02 to 1.17; p-for-trend 0.012). For PM_2.5, 10 unit increase (μg/m³) was associated with an increasing risk of seropositivity by 1.65 (95% CI 1.015-2.68; p-for-trend 0·049). In addition, we found that NO₂ was positively associated with higher antibody titres (p-for-trend 0·013) among seropositive participants, with no evidence of an association for PM_2.5.

Conclusion: Our findings suggest that the long-term burden of air pollution increased the risks of SARS-CoV-2 infection and has important implications for future pandemic preparedness. This evidence strengthens the case for reducing long-term air pollution exposures to reduce the vulnerability of individuals to respiratory viruses.