Study registration: *
Publication Griffin J, MMWR, 2021
Dates: 2020-12-01 to 2021-07-25
Funding: Not reported/unclear
Conflict of interest: no COI (M. Claire Jarashow reports consulting fees from Uber outside the current work and unpaid board membership of two international nongovernmental organizations (C2C and Developing Communities) outside the current work. No other potential conflicts of interest were disclosed.)

Methods

Study design:Cohort
Description of participants: All aged 12 and up residents of Los Angeles County in multiple centres in USA
Inclusion criteria:
  • Aged 16 and up
  • Los Angeles County resident (excluding Pasadena and Long Beach)
  • with outcomes assessed between July 19-25, 2021.

Exclusion criteria:
  • Previous SARS-CoV-2 infection.

Follow-up duration (months): 7.87
Vaccines:
  • 1 or 2 doses of BNT162b2 or mRNA-1273 or 1 dose of Ad26.COV2.S
Variant description :
Variant name: Delta
Evidence: Indirect evidence (prevalence of variant in the population: >87%)
Documents
available

Protocol

NR

Statistical plan

NR

Data-sharing stated: NR
Data accessibility: NR
General comment In addition to the published report, the supplementary material was used in data extraction and risk of bias assessment. The July 25, 2021 timepoint was extracted. 55.2% had received the Pfizer-BioNTech vaccine, 28.0% had received the Moderna vaccine, and 16.8% had received the Janssen (Johnson & Johnson) vaccine. Study start date of vaccinations was not reported; an estimate of December 2020 was used for California (https://covid19.ca.gov/vaccination-progress-data/).
Substantial concern over the likelihood of uncontrolled confounding.