COVID vaccines reduce severe disease

Updated COVID-19 vaccines were linked to fewer hospitalizations and no new safety concerns.
*Systematic review of mixed study designs; Level 2a (OCEBM).

Citation

Lipson RA, Senerth E, Watson MA, et al. COVID-19 Vaccine Effectiveness and Safety for the 2026-2027 Respiratory Season. JAMA. Published online September 2, 2026. doi:10.1001/jama.2026.18191

Background

COVID-19 remains a major cause of respiratory illness, hospitalization, and death, especially in older adults and infants. This review updated evidence on United States-licensed COVID-19 vaccines for effectiveness, safety, and United States disease burden.

Patients

People of all ages and risk groups. Excluded: abstracts, preprints, gray literature, reviews, commentaries, letters, non-English papers, and case series with fewer than 10 people.

Intervention

Any United States-licensed COVID-19 vaccine, including updated formulations and vaccination during pregnancy.

Control

No vaccine, no updated dose, or prior older vaccine formulation.

Outcome

Hospitalization, emergency or urgent care visits, intensive care admission, death, infection, post-COVID symptoms, and prespecified safety outcomes.

Follow-up Period

Search covered August 1, 2025, through June 29, 2026.

Results

The review included 155 publications: 15 randomized trials, 84 comparative observational studies, 38 single-group safety studies, and 18 burden studies.

Population Outcome Key result
Adults ≥65 years Hospitalization 53.0% lower risk (95% confidence interval 37.0% to 65.0%)
Adults 18-64 years Hospitalization 54.0% lower risk (95% confidence interval 1.0% to 78.0%)
Pregnant people Emergency or urgent care visits 58.0% lower risk (95% confidence interval 24.0% to 77.0%)
Children 9 months-4 years Emergency or urgent care visits 76.0% lower risk (95% confidence interval 58.0% to 87.0%)
Health care personnel Post-COVID symptoms 57.0% lower risk (95% confidence interval 46.0% to 66.0%)

Most effectiveness estimates were from adjusted observational studies; no pooled meta-analysis was performed. Safety findings were consistent with prior reviews, with no new safety signals.

Limitations

Many studies were observational and at serious or critical risk of bias from confounding. Single-group safety studies cannot prove causation. Results varied by population, season, and vaccine formulation.

Funding

Philanthropic funding; funder reported no study role.

Clinical Application

Recommend updated COVID-19 vaccination for eligible patients, especially older adults, pregnancy, infants, children, and high-risk groups.