Vaccine Evidence Compendium

RSV vaccines

Benefits of the intervention

Serogroup or serotype coverage by vaccines considered (for serogroup- or serotype-specific vaccines)

Currently authorized RSV immunization products protect against both subgroups of RSV., ,

Efficacy and effectiveness estimates (e.g. against infection, disease, hospitalization, death), including in different populations

Both maternal RSV Pre-F vaccine and the two monoclonal antibody preparations (nirsevimab and clesrovimab) were shown to protect infants against RSV diseases during the first 5-6 months of life.

Maternal vaccination with RSV Pre-F demonstrated efficacy of 70% (95% CI: 50.6- 82.5) against RSV-positive severe medically attended ALRI and 49.2% (95% CI: 31.4, 62.8) against any RSV-positive medically attended LRTI, respectively, up to 180 days after birth.

Similar levels of protection have been observed in post-marketing studies.

In Argentina, maternal vaccination at 32–36 weeks gestation demonstrated vaccine effectiveness (VE) of 71.3% (95% CI: 53.3–82.3) against RSV-associated ALRI hospitalization and 76.9% (95% CI: 45.0–90.3) against severe RSV-associated ALRI hospitalization through six months of age.

In the United Kingdom, during the 2024–2025 RSV season, maternal vaccination from 28 weeks gestation showed VE of 58% (95% CI: 28–75) against infant RSV hospitalization overall and 72% (95% CI: 48–85) when vaccination occurred more than 14 days before delivery. During the 2025-26 season VE of 61% (95% CI: 38-75) against RSV-positive hospital admission in infants aged six months and 76% (95% CI: 54-87) in infants aged <3 months were observed. 

In healthy term and late preterm infants, the efficacy of the mAb (nirsevimab) was 76.4% (95% CI: 62.3- 85.2) against medically attended RSV-associated ALRI, 76.8% (95% CI: 49.4- 89.4) against hospitalization for RSV-associated ALRI and 78.6% (95% CI: 48.8-91.0) against very severe medically attended RSV-associated ALRI up to 5 months after administration. In preterm infants (29-36 weeks gestational age), the efficacy of a single dose of nirsevimab was 70.1% against medically attended RSV ALRI and 78.4% against hospitalized RSV ALRI.

In a large phase 3b randomized study conducted across several European countries in ~8000 full-term infants and preterm infants (born ≥29 weeks’ gestation) entering their first RSV season, nirsevimab reduced hospitalizations due to RSV-associated ALRI by 82.7% (95% CI: 67.8-91.5) over a 180-day follow-up period.

During the first season of use in Chile, combined VE (for seasonal and catch-up cohorts) of nirsevimab was 76.4% (95% CI: 72.5-79.7) against RSV-related ALRI hospitalizations, 84·9% (95% CI: 79.5-89.0) against RSV-related ICU admissions, 66.5% (95% CI: 62.0-70.5) against all-cause ALRI hospitalizations and 47.9% (95% CI: 44.4-51.2) against all-cause hospitalizations.

Administration of nirsevimab was associated with a lower odds of RSV-related hospitalisation (odds ratio 0.17; 95% CI: 0.12–0.23), a lower odds of ICU admission (0.19; 95% CI: 0.12–0.29), and a lower odds of ALRI incidence (0.25; 95% CI: 0.19–0.33) in infants aged 0–12 months in a meta-analysis of the effectiveness of nirsevimab across 27 studies from Spain, France, USA and Luxembourg.

A single injection of 105 mg of clesrovimab showed an efficacy of 60.4% (95% CI: 44.1-71.9) against medically attended ALRI, and efficacy of 84.2% (95% CI: 66.6-92.6) against RSV-associated hospitalization during 150 days of follow up. 

In children at high risk for severe RSV disease entering their second RSV season and eligible for palivizumab (short-acting mAb), incidence rates of RSV-associated medically attended lower respiratory infection were comparable between those who received a single dose of 201 mg of clesrovimab and monthly doses of palivizumab (3.2% and 3.4%, respectively) through day 150 in season 1.

A phase 4 clinical trial (RSV_IMPACT study) is ongoing in four African countries to evaluate the safety and impact of RSV Pre-F maternal vaccine in these settings. The duration of follow up is 365 days after birth; the study is expected to be completed in February 2028.

Duration of protection and waning of immunity in general and risk groups

Both the RSV Pre-F maternal vaccine and nirsevimab provide about 5-6 months of protection to infants.

RSV Pre-F provided protection between 5-6 months following maternal vaccination; RSV antibody titres remained high six months after birth.,

Similarly, efficacy outcomes measured at five months after nirsevimab, and clesrovimab administration indicated protection up to five months., ,

Sources

  • European Medicines Agency (n.d.). Abrysvo: EU summary of product characteristics [product information document]. Amsterdam: EMA (https://www.ema.europa.eu/en/documents/overview/abrysvo-epar-medicine-overview_en.pdf, accessed 17 August 2026).

  • European Medicines Agency (n.d.). Beyfortus: EU summary of product characteristics [product information document]. Amsterdam: EMA (https://www.ema.europa.eu/en/documents/product-information/beyfortus-epar-product-information_en.pdf, accessed 28 June 2026).

  • Syed YY. Clesrovimab: First Approval. Drugs. 2025;85(11):1487-92 doi:10.1007/s40265-025-02224-7.

  • Kampmann B, Madhi SA, Munjal I, Simões EAF, et al. (2023). Bivalent prefusion F vaccine in pregnancy to prevent RSV illness in infants. N Engl J Med. 388:1451–1464. doi:10.1056/NEJMoa2216480.

  • Pérez Marc G, Vizzotti C, Fell DB, Di Nunzio L, Olszevicki S, et al. 2025. Real-world effectiveness of RSVpreF vaccination during pregnancy against RSV-associated lower respiratory tract disease leading to hospitalisation in infants during the 2024 RSV season in Argentina (BERNI study): a multicentre, test-negative, case-control study. Lancet Infect Dis doi:10.1016/s1473-3099(25)00156-2.

  • Williams TC, Marlow R, Cunningham S, Drysdale SB, Groves HE, Hunt S, Iskander D, Liu X, Lyttle MD, Mpamhanga CD, O'Hagan S, Waterfield T, Roland D. 2025. Bivalent prefusion F vaccination in pregnancy and respiratory syncytial virus hospitalisation in infants in the UK: results of a multicentre, test-negative, case-control study. Lancet Child Adolesc Health. doi:10.1016/s2352-4642(25)00155-5.

  • O'Hagan S, Cunningham S, Drysdale SB, Groves HE, Hunt S, et al. A national programme of bivalent prefusion F vaccination in pregnancy and protection against respiratory syncytial virus hospitalisation in infants until age 6 months in the UK: a multicentre, prospective, test-negative, case-control study. Lancet Child Adolesc Health. 2026;10(9):637-46. doi:10.1016/S2352-4642(26)00134-3.

  • Müller WJ, Madhi SA, Seoane Nuñez B, Baca Cots M, Bosheva M, et al. (2023). Nirsevimab for prevention of RSV in term and late-preterm infants. N Engl J Med. 388:1533–1534. doi:10.1056/NEJMc2214773.

  • Griffin MP, Yuan Y, Takas T, Domachowske JB, Madhi SA, et al. (2020). Single-dose nirsevimab for prevention of RSV in preterm infants. N Engl J Med. 383:415–425. doi:10.1056/NEJMoa1913556.

  • Munro APS, Drysdale SB, Cathie K, Flamein F, Knuf M, et al. 2025. 180-day efficacy of nirsevimab against hospitalisation for respiratory syncytial virus lower respiratory tract infections in infants (HARMONIE): a randomised, controlled, phase 3b trial. Lancet Child Adolesc Health 9:404-412. doi:10.1016/S2352-4642(25)00102-6.

  • Torres JP, Sauré D, Goic M, Thraves C, Pacheco J, et al. 2025. Effectiveness and impact of nirsevimab in Chile during the first season of a national immunisation strategy against RSV (NIRSE-CL): a retrospective observational study. Lancet Infect Dis. doi:10.1016/s1473-3099(25)00233-6.

  • Sumsuzzman DM, Wang Z, Langley JM, Moghadas SM. 2025. Real-world effectiveness of nirsevimab against respiratory syncytial virus disease in infants: a systematic review and meta-analysis. Lancet Child Adolesc Health 9:393-403. doi:10.1016/S2352-4642(25)00093-8.

  • Zar HJ, Simoes EAF, Madhi SA, Ramilo O, Senders SD, et al. Clesrovimab for Prevention of RSV Disease in Healthy Infants. N Engl J Med. 2025;393(13):1292-303. doi:10.1056/NEJMoa2502984.

  • Zar HJ, Bont LJ, Manzoni P, Munoz FM, Ramilo O, et al. Clesrovimab in Infants at Increased Risk For Severe Disease During 2 RSV Seasons: A Randomized Clinical Trial. JAMA Pediatr. 2026. doi:10.1001/jamapediatrics.2026.2760.

  • RSV_IMPACT Study: Maternal RSV Vaccination to Protect Infants. University of Witwatersrand; 2025 (https://wrhi.ac.za/projects/rsv_impact-study/, accessed 22 September 2026).

  • United States Food and Drug Administration (2023). Vaccines and Related Biological Products Advisory Committee meeting, 18 May 2023: FDA briefing document. Silver Spring (MD): US FDA (https://www.fda.gov/media/168185/download, accessed 28 June 2026).

  • Kampmann B, Madhi SA, Munjal I, Simões EAF, Pahud BA et al. (2023). Bivalent prefusion F vaccine in pregnancy to prevent RSV illness in infants. N Engl J Med. 388:1451–64. doi: 10.1056/NEJMoa2216480.

  • Simões EAF, Madhi SA, Muller WJ, Atanasova V, Bosheva M, et al. (2023). Efficacy of nirsevimab against respiratory syncytial virus lower respiratory tract infections in preterm and term infants, and pharmacokinetic extrapolation to infants with congenital heart disease and chronic lung disease: a pooled analysis of randomized controlled trials. Lancet Child Adolesc Health. 7(3):180–89. doi:10.1016/S2352-4642(22)00321-2.

  • Zar HJ, Simoes EAF, Madhi SA, Ramilo O, Senders SD, et al. Clesrovimab for Prevention of RSV Disease in Healthy Infants. N Engl J Med. 2025;393(13):1292-303. doi:10.1056/NEJMoa2502984.

  • Zar HJ, Bont LJ, Manzoni P, Munoz FM, Ramilo O, et al. Clesrovimab in Infants at Increased Risk For Severe Disease During 2 RSV Seasons: A Randomized Clinical Trial. JAMA Pediatr. 2026 doi:10.1001/jamapediatrics.2026.2760.

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