Descriptive overview of the study population at start of follow-up.

Descriptive overview of the study population at start of follow-up.</p

Crude vaccine effectiveness against SARS-CoV-2 reinfection during periods of Alpha, Delta, or Omicron dominance.

(DOCX)</p

Definition of country of origin.

(DOCX)</p

Adjusted VE against SARS-CoV-2 reinfection during periods of Alpha, Delta, or Omicron dominance.

(A) Alpha variant (B.1.1.7), 20 February–15 June 2021. (B) Delta variant (B.1.617.2), 4 July–20 November 2021. (C) Omicron variant (B.1.1.529), 21 December 2021–31 January 2022. VE adjusted for age, sex, country of origin, comorbidity, staying at hospital, calendar time, and test incidence. CI, confidence interval; SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2; VE, vaccine effectiveness.</p

Checklist of items that should be included in reports of <i>cohort studies</i>.

(DOC)</p

Adjusted VE against SARS-CoV-2 reinfection during periods of Alpha, Delta, or Omicron dominance.

Adjusted VE against SARS-CoV-2 reinfection during periods of Alpha, Delta, or Omicron dominance.</p

Events in the study population (all ages) and proportion among those 65 years or older during periods of Alpha, Delta, or Omicron dominance.

(DOCX)</p

Overview of ICD-10 codes included in the comorbidity variable.

(DOCX)</p