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

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).

We assessed the associations between long-term (2015-19) nitrogen dioxide (NO₂) and fine particulate matter with an aerodynamic diameter of ≤2.5 microm (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.

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 (microg/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 (microg/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.

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.