Study registration: *
Publication Liu C, medRxiv, 2021
Dates: 2020-12-04 to 2021-09-21
Funding: Public/non profit (The National Library of Medicine/National Human Genomic Research Institute and the National Institute of Allergy and Infectious Diseases of the National Institutes of Health )
Conflict of interest: no COI (The authors declare no competing interest)

Methods

Study design:Cohort
Description of participants: Adults including elderly and co-morbidities with no history of COVID-19 in multiple centres in New York, USA
Inclusion criteria:
  • Individuals older than 18 years
  • residing in New York City
  • no evidence of SARS-CoV-2 infection before entry date
  • attended Columbia University Irving Medical Center/New York Presbyterian (CUIMC/NYP)
  • tested between January 18, 2021 to September 21, 2021

Exclusion criteria:
  • Received doses from more than one manufacturer
  • received only one vaccine dose

Follow-up duration (months): 9.70
Vaccines:
  • 2 doses of BNT162b2 or 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
Data accessibility: The original EHR data used for the current study are available from the corresponding authors on reasonable requests and institutional approvals. Dr. Chunhua Weng had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The code to replicate this study in another OMOP compatible database is available in https://github.com/WengLab-InformaticsResearch/Covid19-Breakthrough Corresponding author: Chunhua Weng, PhD; Email: cw2384@cumc.columbia.edu
General comment In addition to the preprint, the supplementary material were used in data extraction and risk of bias assessment. Authors used matching and adjustment to account for confounding. 78.8% received Pfizer/BNT162b2, while 21.2% received Moderna/mRNA-1273. The infections table (eTable 2) appears to have a date typographical error; it states after "June" 18, 2021 but the text and other figures indicate this should probably be after "January" 18, 2021.
Concerns over uncontrolled confounding, missing data on a confounder and (for infection outcomes) the possibility that controls would only be identified if they seek testing; in addition there are uncertainties over the possibility of selection bias in a test-negative design.