Study registration: *
Publication Bajema K, MMWR, 2021
Dates: 2021-07-01 to 2021-08-06
Funding: Not reported/unclear
Conflict of interest: no COI (Vincent C. Marconi reports research grants from Eli Lilly and Co., Gilead Sciences, and ViiV Healthcare. No other potential conflicts of interest were disclosed.)

Methods

Study design:Test-negative
Description of participants: U.S. veterans hospitalized at five Veterans Affairs Medical Centers (VAMCs) in USA.
Inclusion criteria:
  • Adults aged ≥18 years
  • hospitalized at five VAMCs (in Atlanta, Georgia
  • Bronx, New York
  • Houston, Texas
  • Los Angeles, California
  • and Palo Alto, California)
  • Patients were eligible for inclusion if they had COVID-19–like illness (i.e., fever, new or worsened cough or shortness of breath, loss of taste or smell, oxygen saturation on room air <94%, requirement for noninvasive ventilation or endotracheal intubation with mechanical ventilation, or chest radiograph or computed tomography pulmonary findings consistent with pneumonia) and a molecular test (reverse transcription–polymerase chain reaction [RT-PCR] or isothermal nucleic acid amplification test) for SARS-CoV-2 performed within 14 days before admission or during the first 72 hours of hospitalization.

Exclusion criteria:
  • Participants who received only 1 dose of an mRNA COVID-19 vaccine, 2 mRNA doses with receipt of the second dose <14 days before the qualifying SARS-CoV-2 test, mixed mRNA vaccine products (i.e., a different product for each dose), or the Janssen (Johnson & Johnson) COVID-19 vaccine

Follow-up duration (months): 1.2
Vaccines:
  • 2 doses of BNT162b2
  • 2 doses of mRNA-1273
  • 2 doses of either BNT162b2 or mRNA-1273
Variant description :
Variant name: Delta
Evidence: Direct evidence (effectiveness determined by sequencing cases)
Documents
available

Protocol

NR

Statistical plan

NR

Data-sharing stated: NR
Data accessibility: NR
General comment Some concerns regarding residual confounding and bias in the selection of participants into the study.