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Cited by 707SARS-CoV-2 and COVID-19 ResearchVaccine Coverage and HesitancyCOVID-19 epidemiological studies

Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

Open access
Thompson, Mark G., Burgess, Jefferey L., Naleway, Allison L., Tyner, Harmony L., Yoon, Sarang K., Meece, Jennifer, Olsho, Lauren E.W., Caban-Martinez, Alberto J. +36 more·2021·MMWR. Morbidity and Mortality Weekly Report
DOI 10.15585/mmwr.mm7013e3PMC PMC8022879
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Abstract

In contrast, among fully immunized (≥14 days after second dose) persons, 0.04 infections per 1,000 person-days were reported, and among partially immunized (≥14 days after first dose and before second dose) persons, 0.19 infections per 1,000 person-days were reported. Estimated mRNA vaccine effectiveness for prevention of infection, adjusted for study site, was 90% for full immunization and 80% for partial immunization. These findings indicate that authorized mRNA COVID-19 vaccines are effective for preventing SARS-CoV-2 infection, regardless of symptom status, among working-age adults in real-world conditions. COVID-19 vaccination is recommended for all eligible persons.

AI snapshot

Written from the paper’s full text.

TL;DR

In prospective cohorts across eight U.S. locations during December 14, 2020–March 13, 2021, mRNA COVID-19 vaccines were highly effective against RT-PCR–confirmed SARS-CoV-2 infection among health care personnel, first responders, and other essential and frontline workers. Adjusted vaccine effectiveness was 90% for full immunization and 80% for partial immunization.

Key findings

  • Among 3,950 participants with no previous laboratory documentation of SARS-CoV-2 infection, 205 (5.2%) had RT-PCR–confirmed infection; 2,479 (62.8%) received both recommended mRNA doses and 477 (12.1%) received only one dose.
  • Infection incidence was 1.38 per 1,000 person-days among unvaccinated participants, 0.19 among partially immunized participants, and 0.04 among fully immunized participants.
  • Adjusted mRNA vaccine effectiveness was 90% (95% CI = 68%–97%) for full immunization (≥14 days after second dose) and 80% (95% CI = 59%–90%) for partial immunization (≥14 days after first dose and before second dose).
  • Most PCR-confirmed infections (87.3%) were associated with COVID-19–associated illness symptoms; 10.7% had no symptoms, and only 22.9% were medically attended, including two hospitalizations and no deaths.

Methods

  • HEROES-RECOVER longitudinal cohorts in eight U.S. locations enrolled health care personnel, first responders, and other essential and frontline workers; the vaccine effectiveness analytic sample included 3,950 participants after exclusions.
  • Participants completed weekly active symptom surveillance and self-collected midturbinate nasal swabs weekly regardless of symptom status, plus additional nasal swab and saliva specimens at onset of COVID-19–associated illness; specimens were tested by RT-PCR at Marshfield Clinic Laboratory.
  • Hazard ratios were estimated with the Andersen-Gill extension of the Cox proportional hazards model accounting for time-varying vaccination status; vaccine effectiveness was calculated as 100% × (1−hazard ratio), with an adjusted model including study site and sensitivity analyses adding sex, age, ethnicity, and occupation individually.

Limitations

  • The paper states that vaccine effectiveness estimates should be interpreted cautiously because of moderately wide confidence intervals from limited postimmunization PCR-confirmed infections; this also precluded product-specific estimates and limited adjustment for potential confounders.
  • The paper states that self-collection of specimens and shipment delays could reduce PCR sensitivity; if this disproportionately affected vaccinated persons, vaccine effectiveness would be overestimated.
  • Evident from the text: this is an observational interim analysis over 13 weeks, so residual confounding and limited generalizability are possible; participants were predominantly female, White, non-Hispanic, aged 18–49 years, and without chronic conditions.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.15585/mmwr.mm7013e3

Cites

3 of 3 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 6 cited sources checked · 0 supported · 0 flagged

  • Findingown data
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    Estimated adjusted mRNA vaccine effectiveness for prevention of infection was 90% (95% CI = 68%-97%) for full immunization (≥14 days after second dose).

    “Estimated mRNA vaccine effectiveness for prevention of infection, adjusted for study site, was 90% for full immunization”
    • Also stated in: § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021 · hedged
      “Estimated adjusted vaccine effectiveness of full immunization was 90% (95% confidence interval [CI] = 68%–97%);”
    • Also stated in: § Discussion · plain
      “Vaccine effectiveness of full immunization with two doses of mRNA vaccines was 90% (95% CI = 68%–97%) against RT-PCR–confirmed SARS-CoV-2 infection.”
    Quote in the paperSubstantial claim
  • Findingown data
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    Among unvaccinated participants, 1.38 SARS-CoV-2 infections were confirmed per 1,000 person-days.

    “Among unvaccinated participants, 1.38 SARS-CoV-2 infections were confirmed by reverse transcription–polymerase chain reaction (RT-PCR) per 1,000 person-days.”
    • Also stated in: § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021 · plain
      “During the 116,657 person-days when participants were unvaccinated, 161 PCR-confirmed infections were identified (incidence rate = 1.38/1,000 person-days).”
    Quote in the paperSubstantial claim
  • Findingown data
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    Among fully immunized persons (≥14 days after second dose), 0.04 SARS-CoV-2 infections were reported per 1,000 person-days.

    “In contrast, among fully immunized (≥14 days after second dose) persons, 0.04 infections per 1,000 person-days were reported”
    • Also stated in: § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021 · plain
      “Three PCR-confirmed infections occurred during 78,902 person-days with full immunization (≥14 days after second dose; incidence rate = 0.04/1,000 person-days).”
    Quote in the paperSubstantial claim
  • Findingown data
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    Estimated adjusted mRNA vaccine effectiveness for prevention of infection was 80% (95% CI = 59%-90%) for partial immunization (≥14 days after first dose and before second dose).

    “and 80% for partial immunization.”
    • Also stated in: § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021 · plain
      “vaccine effectiveness of partial immunization was 80% (95% CI = 59%–90%) (Table 2).”
    • Also stated in: § Discussion · plain
      “Partial immunization (≥14 days after first dose but before second dose) provided preventive benefits with vaccine effectiveness of 80%.”
    Quote in the paperSubstantial claim
  • Findingown data
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    Among partially immunized persons (≥14 days after first dose and before second dose), 0.19 SARS-CoV-2 infections were reported per 1,000 person-days.

    “and among partially immunized (≥14 days after first dose and before second dose) persons, 0.19 infections per 1,000 person-days were reported.”
    • Also stated in: § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021 · plain
      “Taken together, this represents eight PCR-confirmed infections that occurred during 41,856 person-days with partial immunization (≥14 days after first dose and before second dose; incidence rate = 0.19/1,000 person-days).”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 7
  • May combine two claims. 5

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    The majority of PCR-confirmed infections were identified by weekly specimens (58.0%), whereas 42.0% were identified from specimens collected at the onset of COVID-19-associated illness.

    “The majority of PCR-confirmed infections were identified by weekly specimens (58.0%), whereas 42.0% were identified from specimens collected at the onset of COVID-19–associated illness.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    Overall, 3,950 participants were included in the vaccine effectiveness analytic sample.

    “Overall, 3,950 participants in the vaccine effectiveness analytic sample were analyzed.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    The majority (87.3%) of PCR-confirmed infections were associated with symptoms consistent with COVID-19-associated illness; 2.0% were associated with other symptoms not part of the COVID-19-associated illness definition, and 10.7% were asymptomatic.

    “Nonetheless, the majority (87.3%) of PCR-confirmed infections were associated with symptoms consistent with COVID-19–associated illness. The remaining PCR-confirmed infections were associated with other symptoms not part of the COVID-19–associated illness definition (e.g., headache, fatigue, and rhinorrhea) (2.0%) or no symptoms (10.7%).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    The adjusted vaccine effectiveness model included study site as a covariate.

    “An adjusted vaccine effectiveness model included study site as a covariate.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    Over the 13-week study period, adherence to weekly surveillance reporting and specimen collection was high (median = 100%; interquartile range = 82%-100%).

    “Over the 13-week study period, adherence to weekly surveillance reporting and specimen collection was high (median = 100%; interquartile range = 82%–100%).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Vaccine effectiveness point estimates should be interpreted with caution given the moderately wide confidence intervals attributable in part to the limited number of postimmunization PCR-confirmed infections observed.

    “First, vaccine effectiveness point estimates should be interpreted with caution given the moderately wide CIs attributable in part to the limited number of postimmunization PCR-confirmed infections observed.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductcitation

    Self-collection of specimens and delays in shipments could reduce sensitivity of virus detection by PCR; if this disproportionately affected those who received the vaccine, vaccine effectiveness would be overestimated.

    “Finally, self-collection of specimens and delays in shipments could reduce sensitivity of virus detection by PCR (10); if this disproportionately affected those who received the vaccine (e.g., because of possible vaccine attenuation of virus shedding), vaccine effectiveness would be overestimated.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] McCulloch, 2020, Comparison of unsupervised home self-collected midnasal swabs with clinician-collected nasopharyngeal swabs for detection of SARS-CoV-2 infection., JAMA Netw Open source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation
    § Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021

    Messenger RNA (mRNA) BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) COVID-19 vaccines have been shown to be effective in preventing symptomatic COVID-19 in randomized placebo-controlled Phase III trials.

    “Messenger RNA (mRNA) BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) COVID-19 vaccines have been shown to be effective in preventing symptomatic COVID-19 in randomized placebo-controlled Phase III trials (1,2);”
    • Also stated in: § What is already known about this topic? · plain
      “Messenger RNA (mRNA) COVID-19 vaccines have been shown to be effective in preventing symptomatic SARS-CoV-2 infection in randomized placebo-controlled Phase III trials.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [1] Baden, 2021, Efficacy and safety of the mRNA-123 SARS-CoV-2 vaccine., N Engl J Med source

      Not checked in the free run.

    • cites [2] Polack, 2020, Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine., N Engl J Med source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    The limited number of postimmunization PCR-confirmed infections precluded making product-specific vaccine effectiveness estimates and limited the ability to adjust for potential confounders.

    “Second, this also precluded making product-specific vaccine effectiveness estimates and limited the ability to adjust for potential confounders; however, effects were largely unchanged when study site was included in an adjusted vaccine effectiveness model and when adjusted for sex, age, ethnicity, and occupation separately in sensitivity analyses.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductreasoning

    The scientific rigor of these findings is enhanced by the prospective design and the participants' very high adherence to weekly specimen collection.

    “The scientific rigor of these findings is enhanced by its prospective design and the participants’ very high adherence to weekly specimen collection.”
    Quote in the paperNot a substantial claim
10 of 10

  • The paper relies on this without support.

    The benefits of mRNA vaccines for preventing asymptomatic and symptomatic SARS-CoV-2 infection, particularly in real-world conditions, are less well understood.

    “however, the benefits of these vaccines for preventing asymptomatic and symptomatic SARS-CoV-2 (the virus that causes COVID-19) infection, particularly when administered in real-world conditions, is less well understood.”

  • The paper relies on this without support.

    The HEROES-RECOVER cohort of health care personnel, first responders, and other essential and frontline workers is representative of working-age adults in real-world conditions.

    “These findings indicate that authorized mRNA COVID-19 vaccines are effective for preventing SARS-CoV-2 infection, regardless of symptom status, among working-age adults in real-world conditions.”
2 of 2

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Cites

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Research works printed but not linked: 7

  1. Pawlowski C, Lenehan P, Puranik A, FDA-authorized COVID-19 vaccines are effective per real-world evidence synthesized across a multi-state health system. medRxiv [Preprint posted online February 27, 2021]. https://www.medrxiv.org/content/10.1101/2021.02.15.21251623v3 · DOI
  2. Amit, 2021, Early rate reductions of SARS-CoV-2 infection and COVID-19 in BNT162b2 vaccine recipients., Lancet, 397, 875, 10.1016/S0140-6736(21)00448-7 · DOI · Paper page
  3. Byambasuren O, Cardona M, Bell K, Clark J, McLaws M-L, Glasziou P. Estimating the extent of asymptomatic COVID-19 and its potential for community transmission: systematic review and meta-analysis. medRxiv [Preprint posted online September 13, 2020]. https://www.medrxiv.org/content/10.1101/2020.05.10.20097543v3 · DOI
  4. Skowronski, 2021, Safety and efficacy of the BNT162b2 mRNA Covid-19 Vaccine., N Engl J Med
  5. Daniel, 2021, Early evidence of the effect of SARS-CoV-2 vaccine at one medical center., N Engl J Med, 10.1056/NEJMc2102153 · DOI
  6. Keehner, 2021, SARS-CoV-2 infection after vaccination in health care workers in California., N Engl J Med, 10.1056/NEJMc2101927 · DOI
  7. McCulloch, 2020, Comparison of unsupervised home self-collected midnasal swabs with clinician-collected nasopharyngeal swabs for detection of SARS-CoV-2 infection., JAMA Netw Open, 3, e2016382, 10.1001/jamanetworkopen.2020.16382 · DOI · Paper page

Cited by

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Authors
Thompson, M. G., Burgess, J. L., Naleway, A. L., Tyner, H. L., Yoon, S. K., Meece, J., Olsho, L. E. W., Caban-Martinez, A. J., Fowlkes, A., Lutrick, K., Kuntz, J. L., Dunnigan, K., Odean, M. J., Hegmann, K. T., Stefanski, E., Edwards, L. J., Schaefer-Solle, N., Grant, L., Ellingson, K., Groom, H. C., Zunie, T., Thiese, M. S., Ivacic, L., Wesley, M. G., Lamberte, J. M., Sun, X., Smith, M. E., Phillips, A. L., Groover, K. D., Yoo, Y. M., Gerald, J., Brown, R. T., Herring, M. K., Joseph, G., Beitel, S., Morrill, T. C., Mak, J., Rivers, P., Harris, K. M., Hunt, D. R., Arvay, M. L., Kutty, P., Fry, A. M., & Gaglani, M.
Affiliations
Marshfield Clinic (US)
Corresponding author
Thompson, Mark G.
ORCID
Venue
MMWR. Morbidity and Mortality Weekly Report
Publisher
Centers for Disease Control MMWR Office
Published
2021-04-02
Volume
70
Issue
13
Pages
495-500
ISSN
  • 0149-2195 (ISSN-L)
  • 1545-861X
DOI
10.15585/mmwr.mm7013e3
PMC
PMC8022879
OpenAlex
W3141986261
Cited by
707
References
3
Citations by year
2026: 13 · 2025: 22 · 2024: 43 · 2023: 91 · 2022: 252 · 2021: 285
FWCI
53.21
Type
journal article
Language
en
Open access
Locations
  • MMWR Morbidity and Mortality Weekly Report (publishedVersion)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Funders
Pfizer
Topics
  • Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
  • Social Sciences › Health › Vaccine Coverage and Hesitancy
  • Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
Keywords
COVID-19 vaccine effectiveness, BNT162b2, mRNA-1273, SARS-CoV-2 infection prevention, healthcare workers, first responders, essential workers, frontline workers, partial immunization, real-world effectiveness, working-age adults
MeSH terms
COVID-19, COVID-19 Vaccines, COVID-19 Nucleic Acid Testing, mRNA Vaccines, BNT162 Vaccine, Adolescent, Adult, Female, Health Personnel, Humans, Male, Middle Aged, Occupational Diseases, Occupations, Prospective Studies, United States, Vaccines, Synthetic, Young Adult, Emergency Responders

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