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Cochrane for Clinicians

Efficacy and Safety of RSV Vaccines

Andrew Foley, MD, MPH,
Instructor in Medicine, Harvard Medical School, Boston, Massachusetts; Family Physician, Massachusetts General Hospital Chelsea Community Health Center, Chelsea

American Family Physician. 2026;114(3):234-235.

Author Disclosure: No relevant financial relationships.

This clinical content conforms to AAFP criteria for CME.

CLINICAL QUESTION

Do respiratory syncytial virus (RSV) vaccines reduce RSV-associated respiratory tract illness in adults? Does vaccination of pregnant patients reduce RSV-associated respiratory tract illness in their infants?

EVIDENCE-BASED ANSWER

RSV vaccines reduce RSV-associated respiratory tract illness in older adults. RSV vaccination of pregnant patients reduces lower respiratory tract infections that require medical attention in their infants, including hospitalization due to RSV disease.1 (Strength of Recommendation: A, consistent, good-quality patient-oriented evidence.)

PRACTICE POINTERS

RSV is a prevalent and highly contagious cause of respiratory tract illness and accounts for approximately 2% of infant deaths worldwide.2 It also increases the risk of secondary otitis media and bacterial pneumonia and their sequelae in infants and children.3,4 RSV can cause severe respiratory tract disease in older adults, especially those with chronic cardiac and pulmonary disease.5 The authors of this Cochrane review sought to evaluate the risks and benefits of RSV vaccines, as well as their effect on RSV-related disease, hospitalization, and mortality.

This Cochrane review included 14 randomized controlled trials with a total of 114,327 patients, most of whom were older adults (n = 99,931; mean age 68.1–69.5 years).1 Seven trials were conducted in the United States, and seven were international, including Europe, South America, Africa, and Asia. The trials evaluated five RSV vaccine formulations, including those not available in the United States. This summary focuses on results for clinically available vaccines approved by the US Food and Drug Administration, all of which target the prefusion protein. Notably, this review did not include monoclonal antibody injections (nirsevimab [Beyfortus] and clesrovimab [Enflonsia]), which are approved for infants in the United States.

The authors considered vaccine effect on RSV illness frequency, hospitalization due to RSV illness, RSV-related mortality, and all-cause mortality.1 The follow-up in all studies was one RSV season. Harms were defined as serious adverse events related to vaccination (eg, neurologic disorders such as Guillain-Barré syndrome). Outcomes were primarily reported as vaccine efficacy (ie, the reduction in risk of disease-related events among vaccinated people compared with placebo). For example, a vaccine efficacy of 0.9 would indicate a 90% reduction in disease-related events in the vaccinated group.

In older adults, the RSV vaccine reduced RSV-associated lower respiratory tract illness (vaccine efficacy = 0.77; 95% CI, 0.70–0.83) and acute respiratory illness (vaccine efficacy = 0.67; 95% CI, 0.60–0.73) but made little to no difference in all-cause mortality.1

Maternal vaccination reduced RSV-associated lower respiratory tract illness that required medical attention in infants (vaccine efficacy = 0.54; 95% CI, 0.28–0.71) and severe RSV-associated illness in infants (vaccine efficacy = 0.74; 95% CI, 0.44–0.88).1 Maternal vaccination also reduced infant hospitalization due to RSV-related illness (vaccine efficacy = 0.54; 95% CI, 0.27–0.71) but made little to no difference in RSV-associated infant mortality. Maternal vaccinations were administered between 24 and 36 weeks' gestation or 28 and 36 weeks' gestation. The review did not assess the effect of maternal vaccination timing on infant outcomes.

Trials that involved older adults were significantly larger and more comprehensive than the others. Across all trials, vaccination resulted in no apparent increase in adverse events.1

The Centers for Disease Control and Prevention (CDC) recommends a single dose of RSV vaccine over a person's lifetime to prevent serious RSV infection in older adults (75 years or older) or adults aged 50 to 74 years at increased risk of severe disease.6 The CDC also recommends RSV vaccination for pregnant individuals between 32 and 36 weeks' gestation to prevent RSV infection in their infants.7

The practice recommendations in this activity are available at https://www.cochrane.org/CD016131​.

Author Disclosure: No relevant financial relationships.

  1. 1.Saif-Ur-Rahman KM, King C, Whelan SO, et al. Efficacy and safety of respiratory syncytial virus vaccines. Cochrane Database Syst Rev. 2025(9):CD016131.
  2. 2.Li Y, Wang X, Blau DM, et al.; Respiratory Virus Global Epidemiology Network; RESCEU Investigators. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis. Lancet. 2022;399(10340):2047-2064.
  3. 3.Dagan R, van der Beek BA, Ben-Shimol S, et al. The COVID-19 pandemic as an opportunity for unravelling the causative association between respiratory viruses and pneumococcus-associated disease in young children: a prospective study. EBioMedicine. 2023;90:104493.
  4. 4.Binns E, Tuckerman J, Licciardi PV, et al. Respiratory syncytial virus, recurrent wheeze and asthma: a narrative review of pathophysiology, prevention and future directions. J Paediatr Child Health. 2022;58(10):1741-1746.
  5. 5.Colosia AD, Yang J, Hillson E, et al. The epidemiology of medically attended respiratory syncytial virus in older adults in the United States: a systematic review. PLoS One. 2017;12(8):e0182321.
  6. 6.Centers for Disease Control and Prevention. RSV vaccine guidance for adults. July 9, 2025. Accessed July 13, 2026. https://www.cdc.gov/rsv/hcp/vaccine-clinical-guidance/adults.html​
  7. 7.Centers for Disease Control and Prevention. RSV vaccine guidance for pregnant people. August 30, 2024. Accessed November 28, 2025. https://www.cdc.gov/rsv/hcp/vaccine-clinical-guidance/pregnant-people.html​

These are summaries of reviews from the Cochrane Library.

This series is coordinated by Corey D. Fogleman, MD, assistant medical editor.

A collection of Cochrane for Clinicians published in AFP is available at https://www.aafp.org/afp/cochrane.

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