PREPRINT: Determinants of pre-vaccination antibody responses to SARS-CoV-2: a population-based longitudinal study (COVIDENCE UK)
Prospective population-based studies investigating multiple determinants of pre-vaccination antibody responses to SARS-CoV-2 are lacking.
We did a prospective population-based study in SARS-CoV-2 vaccine-naive UK adults between May 1 and Nov 2, 2020. Information on 88 potential risk factors was obtained through online questionnaires, and combined IgG/IgA/IgM responses to SARS-CoV-2 spike glycoprotein were determined in dried blood spots. We used logistic and linear regression to estimate adjusted odds ratios (aORs) and adjusted geometric mean ratios (aGMRs) for potential determinants of SARS-CoV-2 seropositivity (all participants) and antibody titres (seropositive participants only), respectively.
1696 (15.2%) of 11,130 participants were seropositive. Factors independently associated with increased risk included frontline health/care occupation (aOR 1.86, 95% CI 1.49–2.33), international travel (1.22, 1.08–1.37), BMI >30 vs <25 kg/m2 (1.22, 1.05–1.42), Asian/Asian British vs White ethnicity (1.65, 1.10–2.47), and alcohol consumption ≥15 vs 0 units/week (1.26, 1.06–1.49). Light physical exercise associated with decreased risk (0.80, 0.69–0.93, for ≥10 vs 0–4 h/week). Higher titres associated with frontline health/care occupation (aGMR 1.26, 95% CI 1.13–1.41), international travel (1.10, 1.04–1.16), BMI >30 vs <25 kg/m2 (1.09, 1.01–1.17), and Asian/Asian British vs White ethnicity (1.23, 1.03–1.46); these associations were not substantially attenuated by adjustment for disease severity.
Higher alcohol consumption and reduced physical exercise represent new modifiable risk factors for SARS-CoV-2 infection. Recognised associations between Asian/Asian British ethnic origin and obesity and increased risk of SARS-CoV-2 seropositivity were independent of other sociodemographic, clinical, or behavioural factors investigated.