Study registration: *
Publication Nordstrom P, SSRN, 2021
Dates: 2020-12-28 to 2021-10-04
Funding: No specific funding (The present study was not funded.)
Conflict of interest: no COI (None to declare.)

Methods

Study design:Cohort
Description of participants: General population including co-morbidities in Sweden.
Inclusion criteria:
  • Fully vaccinated individuals with any Covid-19 vaccine (ChAdOx1 nCoV-19, BNT162b2, or mRNA-1273) in Sweden until 26 May 2021, and all individuals with a confirmed infection until 24 May 2021 with matched unvaccinated individuals.

Exclusion criteria:
  • Matched unvaccinated individuals were excluded if they received a first dose of vaccine or died within 14 days of baseline.

Follow-up duration (months): 9.2
Vaccines:
  • 2 doses of BNT162b2, mRNA-1273 or ChAdOx1-S OR 1 dose of ChAdOx1-S and 1 dose of BNT162b2 or mRNA-12
  • 2 doses of BNT162b2
  • 2 doses of mRNA-1273
  • 2 doses of ChAdOx1-S
  • 1 dose of ChAdOx1-S and 1 dose of BNT162b2 or 1 dose of mRNA-1273
Variant description :
Variant name: Delta
Evidence: Indirect evidence (prevalence of variant in the population: 1 to 99%)
Documents
available

Protocol

NR

Statistical plan

NR

Data-sharing stated: Yes, Now
Data accessibility: The data files used for the present study is publicly unavailable according to regulations under Swedish law. However, all data used for the present study can be applied for from the National Board of Health and Welfare, Statistics Sweden, and the Public Health Agency of Sweden.
General comment Concerns over the lack of adjustment for important confounders, potential misclassificiation of the symptomatic outcome, and exclusion of those previously infected or who died within 14 days.