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. 2022 May;16(3):585-593.
doi: 10.1111/irv.12956. Epub 2022 Jan 13.

Incidence of SARS-CoV-2 infection among COVID-19 vaccinated and unvaccinated healthcare personnel, first responders, and other essential and frontline workers: Eight US locations, January-September 2021

Allison L Naleway  1 , Lauren Grant  2 , Alberto J Caban-Martinez  3 , Meredith G Wesley  4 , Jefferey L Burgess  5 , Kimberly Groover  4 , Manjusha Gaglani  6   7 , Sarang K Yoon  8 , Harmony L Tyner  9 , Jennifer Meece  10 , Jennifer L Kuntz  1 , Young M Yoo  2 , Natasha Schaefer-Solle  3 , Lauren E W Olsho  4 , Joe K Gerald  5 , Spencer Rose  6   7 , Matthew S Thiese  8 , Jessica Lundgren  9 , Holly C Groom  1 , Josephine Mak  2 , Paola Louzado Feliciano  3 , Laura J Edwards  4 , Karen Lutrick  5 , Kayan Dunnigan  6   7 , Andrew L Phillips  8 , Julie Mayo Lamberte  2 , Roger Noriega  3 , Brian E Sokol  4 , Marilyn Odean  11 , Katherine D Ellingson  5 , Michael Smith  4 , Kurt T Hegmann  8 , Karley Respet  9 , Monica Dickerson  2 , Alexandra Cruz  3 , Deanna E Fleary  4 , Kempapura Murthy  6 , Angela Hunt  9 , Eduardo Azziz-Baumgartner  2 , Damena Gallimore-Wilson  3 , Jenna A Harder  4 , Leah Odame-Bamfo  6 , Jennifer Viergutz  9 , Melissa Arvay  2 , John M Jones  3 , Peenaz Mistry  4 , Mark G Thompson  2 , Ashley L Fowlkes  2
Affiliations

Incidence of SARS-CoV-2 infection among COVID-19 vaccinated and unvaccinated healthcare personnel, first responders, and other essential and frontline workers: Eight US locations, January-September 2021

Allison L Naleway et al. Influenza Other Respir Viruses. 2022 May.

Abstract

Background: We sought to evaluate the impact of changes in estimates of COVID-19 vaccine effectiveness on the incidence of laboratory-confirmed infection among frontline workers at high risk for SARS-CoV-2.

Methods: We analyzed data from a prospective frontline worker cohort to estimate the incidence of COVID-19 by month as well as the association of COVID-19 vaccination, occupation, demographics, physical distancing, and mask use with infection risk. Participants completed baseline and quarterly surveys, and each week self-collected mid-turbinate nasal swabs and reported symptoms.

Results: Among 1018 unvaccinated and 3531 fully vaccinated workers, the monthly incidence of laboratory-confirmed SARS-CoV-2 infection in January 2021 was 13.9 (95% confidence interval [CI]: 10.4-17.4), declining to 0.5 (95% CI -0.4-1.4) per 1000 person-weeks in June. By September 2021, when the Delta variant predominated, incidence had once again risen to 13.6 (95% CI 7.8-19.4) per 1000 person-weeks. In contrast, there was no reportable incidence among fully vaccinated participants at the end of January 2021, and incidence remained low until September 2021 when it rose modestly to 4.1 (95% CI 1.9-3.8) per 1000. Below average facemask use was associated with a higher risk of infection for unvaccinated participants during exposure to persons who may have COVID-19 and vaccinated participants during hours in the community.

Conclusions: COVID-19 vaccination was significantly associated with a lower risk of SARS-CoV-2 infection despite Delta variant predominance. Our data demonstrate the added protective benefit of facemask use among both unvaccinated and vaccinated frontline workers.

Keywords: SARS-CoV-2; essential worker; vaccine.

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Conflict of interest statement

All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Allison L. Naleway reported institutional funding from Pfizer and Vir Biotechnology for studies unrelated to the submitted work and Jennifer Kuntz receives research funding from Pfizer, Novartis, and Vir Biotechnology for unrelated studies. Matthew S. Thiese reports grants and personal fees from Reed Group and the American College of Occupational and Environmental Medicine, outside the submitted work. No other potential conflicts of interest were disclosed. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

Figures

FIGURE 1
FIGURE 1
Monthly incidence* of SARS‐CoV‐2 among unvaccinated and fully COVID‐19 vaccinated frontline workers—January–September 2021. The unadjusted incidence was calculated for each month as the number of infections relative to the observed person‐weeks, and 95% confidence intervals were estimated using Wald intervals
See this image and copyright information in PMC

References

    1. Baden LR, el Sahly HM, Essink B, et al. Efficacy and safety of the mRNA‐1273 SARS‐CoV‐2 vaccine. N Engl J Med. 2021;384(5):403‐416. - PMC - PubMed
    1. 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. 2021;70(34):1167‐1169. - PMC - PubMed
    1. Polack FP, Thomas SJ, Kitchin N, et al. Safety and efficacy of the BNT162b2 mRNA Covid‐19 vaccine. N Engl J Med. 2020;383(27):2603‐2615. - PMC - PubMed
    1. Sadoff J, Gray G, Vandebosch A, et al. Safety and efficacy of single‐dose Ad26.COV2.S vaccine against Covid‐19. N Engl J Med. 2021;384(23):2187‐2201. - PMC - PubMed
    1. Thompson MG, Burgess JL, Naleway AL, et al. Prevention and attenuation of Covid‐19 with the BNT162b2 and mRNA‐1273 vaccines. N Engl J Med. 2021;385(4):320‐329. - PMC - PubMed

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