Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 May 16;225(10):1694-1700.
doi: 10.1093/infdis/jiab619.

Effectiveness of mRNA Vaccines Against COVID-19 Hospitalization by Age and Chronic Medical Conditions Burden Among Immunocompetent US Adults, March-August 2021

Collaborators, Affiliations

Effectiveness of mRNA Vaccines Against COVID-19 Hospitalization by Age and Chronic Medical Conditions Burden Among Immunocompetent US Adults, March-August 2021

Nathaniel M Lewis et al. J Infect Dis. .

Abstract

Vaccine effectiveness (VE) against COVID-19 hospitalization was evaluated among immunocompetent adults (≥18 years) during March-August 2021 using a case-control design. Among 1669 hospitalized COVID-19 cases (11% fully vaccinated) and 1950 RT-PCR-negative controls (54% fully vaccinated), VE was 96% (95% confidence interval [CI], 93%-98%) among patients with no chronic medical conditions and 83% (95% CI, 76%-88%) among patients with ≥ 3 categories of conditions. VE was similar between those aged 18-64 years versus ≥65 years (P > .05). VE against severe COVID-19 was very high among adults without chronic conditions and lessened with increasing comorbidity burden.

Keywords: COVID-19; chronic medical conditions; preexisting conditions; vaccine effectiveness.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Vaccine effectiveness by age group and number of chronic medical conditions. Adjusted vaccine effectiveness (VE) was estimated using logistic regression comparing odds of being fully vaccinated with an mRNA COVID-19 vaccine versus being unvaccinated, in case patients and control patients, using the equation VE = 100 × (1 − odds ratio). Overall VE by number of condition categories documented (0, 1, 2, or ≥ 3) was calculated by including an interaction term between vaccination status and number of condition categories. An additional model including a 3-way interaction between age, conditions, and vaccination status was included to calculate VE by number of condition categories within age groups. Models were additionally adjusted for date of hospital admission (biweekly intervals), US Department of Health and Human Services region of hospital, age (continuous), sex, and race/ethnicity (non-Hispanic white, non-Hispanic black, Hispanic of any race, non-Hispanic other, or unknown), and number of condition categories. VE point estimates are rounded to the nearest whole number. Error bars represent 95% confidence intervals.

References

    1. Centers for Disease Control and Prevention. COVID data tracker. https://covid.cdc.gov/covid-data-tracker/#datatracker-home. Accessed 28 September 2021.
    1. Sadarangani M, Marchant A, Kollmann TR.. Immunological mechanisms of vaccine-induced protection against COVID-19 in humans. Nat Rev Immunol 2021; 21:475–84. - PMC - PubMed
    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; 384:403–16. - PMC - PubMed
    1. El Sahly H, Baden LR, Essink B, et al. . Efficacy of the mRNA-1273 SARS-CoV-2 vaccine at completion of blinded phase. N Engl J Med 2021; 385:1774–85. - PMC - PubMed
    1. Self WH, Tenforde MW, Rhoads JP, et al. . Comparative effectiveness of Moderna, Pfizer-BioNTech, and Janssen (Johnson & Johnson) vaccines in preventing COVID-19 hospitalizations among adults without immunocompromising conditions—United States, March–August 2021. MMWR Morb Mortal Wkly Rep 2021; 70:1337–43. - PMC - PubMed

Publication types