RSV Vaccine in Pregnancy Halves Severe Baby Cases

How Does RSV Vaccination in Pregnancy Protect Newborns?

When a pregnant woman receives the RSV vaccine from week 28 of gestation, her body produces antibodies that cross the placenta and reach the baby before birth. This passive immunity shields infants during their first months of life — the window when respiratory complications are most dangerous.

What Do the Latest Brazilian Data Show?

Figures presented on 14 July 2026 at the 7th Ordinary Meeting of the SUS Tripartite Intergestors Commission (CIT) are striking. In the first half of 2026, severe acute respiratory syndrome (SARS) cases among babies under 6 months dropped from 14,061 to 6,674 compared with the same period in 2025 — a fall of 52.5%. Among other childhood age groups the reduction was between 8% and 13%, confirming the strongest effect is among babies covered by maternal immunisation.

How Many Doses Have Been Given?

The RSV vaccine has been available free through Brazil's public health system (SUS) since December 2024. More than 1.2 million doses have already been administered nationwide. A parallel study estimates that vaccination has prevented approximately 6,800 severe cases in babies under 6 months.

Is There Protection for Babies Who Weren't Covered In Utero?

Yes. The SUS also offers nirsevimab, a ready-made monoclonal antibody that begins working immediately after a single injection, without waiting for the body to build its own response. It provides protection for up to six months and is indicated for premature newborns (up to 36 weeks and 6 days of gestation) and children up to 23 months with comorbidities such as congenital heart disease or chronic lung conditions. More than 100,000 doses have been recorded. Nirsevimab is available in maternity hospitals and through the CRIE network.