Effectiveness of COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Frontline Workers Before and During B.1.617.2 (Delta) Variants Predominance — Eight U.S. Locations, December 2020–August 2021

Details

• Personal Author:
  Fowlkes, Ashley ; Gaglani, Manjusha ; Groover, Kimberly ; Thiese, Matthew S. ; Tyner, Harmony ; Ellingson, Katherine
• Corporate Authors:
  CDC COVID-19 Response Team. ; Baylor Scott & White Health. ; Abt Associates, Inc. ; University of Utah. ; St. Luke’s Regional Health Care System (Duluth, Minnesota) ; University of Arizona. Mel and Enid Zuckerman College of Public Health. ; HEROES-RECOVER Cohorts.
• Description:
  During December 14, 2020–April 10, 2021, data from the HEROES-RECOVER Cohorts,* a network of prospective cohorts among frontline workers, showed that the Pfizer-BioNTech and Moderna mRNA COVID-19 vaccines were approximately 90% effective in preventing symptomatic and asymptomatic infection with SARS-CoV-2, the Virus that causes COVID-19, in real-world conditions (1,2). This report updates vaccine effectiveness (VE) estimates including all COVID-19 vaccines available through August 14, 2021, and examines whether VE differs for adults with increasing time since completion of all recommended vaccine doses. VE before and during SARS-CoV-2 B.1.617.2 (Delta) Variants predominance, which coincided with an increase in reported COVID-19 vaccine breakthrough infections, were compared (3,4).
  
  Methods for the HEROES-RECOVER Cohorts have been published previously (1,2,5). Health care personnel, first responders, and other essential and frontline workers in eight U.S. locations across six states were tested weekly for SARS-CoV-2 infection by reverse transcription–polymerase chain reaction (RT-PCR)† and upon the onset of any COVID-19–like illness. Weeks when the Delta Variants accounted for ≥50% of Viruses sequenced, based on data from each respective location, were defined as weeks of Delta Variants predominance. Vaccination was documented by self-report and verified by provision of vaccine cards or extraction from electronic medical records or state immunization registries. Among 4,217 participants, 3,483 (83%) were vaccinated; 2,278 (65%) received Pfizer-BioNTech, 1,138 (33%) Moderna, and 67 (2%) Janssen (Johnson & Johnson) COVID-19 vaccines. Cox proportional hazards models were used to calculate ratios of unvaccinated to fully vaccinated (≥14 days after receipt of all recommended COVID-19 vaccine doses) infection rates, adjusted for occupation, site, and local viral circulation (6), and weighted for inverse probability of vaccination using sociodemographic characteristics, health information, frequency of close social contact, and mask use. This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy.§
  
  Suggested citation for this article: Fowlkes A, Gaglani M, Groover K, et al. Effectiveness of COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Frontline Workers Before and During B.1.617.2 (Delta) Variant Predominance — Eight U.S. Locations, December 2020–August 2021. MMWR Morb Mortal Wkly Rep. ePub: 24 August 2021.
  
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  mm7034e4-H.pdf
  
  
• Subjects:
  CoronaVirus Infections/Prevention & Control COVID-19 Vaccines COVID-19/Epidemiology COVID-19/Prevention & Control Emergency Responders Health Personnel Occupational Diseases Occupations
• Source:
  MMWR: Morbidity and Mortality Weekly Report 2021; v. 70 Early Release
• Series:
  Weekly Report: Morbidity and Mortality Weekly Report (MMWR)
• ISSN:
  0149-2195 (print) ; 1545-861X (digital)
• Document Type:
  Journal Article
• Name as Subject:
  Moderna Covid-19 Vaccine ; Pfizer-BioNTech COVID-19 Vaccine
• Place as Subject:
  United States
• Pages in Document:
  3 pdf pages
• Volume:
  70
• Collection(s):
  Morbidity and Mortality Weekly Report (MMWR)
• Main Document Checksum:
  urn:sha-512:92dd83bab8369b9616020876d11287a1ed511f55383081030aa9b9d2d34ee2bfdc3e9508fe01a4366380e01f852d9f544c858d0e05c8f24b24a3719842e2c808
• Download URL:
  https://stacks.cdc.gov/view/cdc/109175/cdc_109175_DS1.pdf
• File Type:
  [PDF - 209.77 KB ]