The admission ledger

Denmark began offering pregnant women an RSV vaccine in autumn 2025, aiming to protect babies in their first months. In the 2025-26 RSV season, hospital admissions among infants aged 0 to 5 months fell from a three-season average of 1,128 to 296 — a 75 per cent drop. A team from the University of Copenhagen and Nordsjællands Hospital paired hospital stays longer than 12 hours with a positive RSV test in Statens Serum Institut surveillance data; 296 admissions were counted between 1 October 2025 and 29 April 2026.[1]

Thea Kølsen Fischer reads the figure as more than 800 infants who may have avoided admission; RSV can inflame the smallest airways and build up mucus. Clinicians' daily observation points the same way: paediatric departments say they did not see the usual surge this winter. Still, the table alone does not prove vaccine effect; shifts in transmission and testing activity could also move the numbers.[1]

Uptake and the limit

The University of Copenhagen and Nordsjællands Hospital state plainly that a direct causal link between vaccination and the decline cannot be established. The pattern matches programmes in Belgium, Spain, the Netherlands, France and England; in the table the Nordsjællands Hospital team relayed, shifts in transmission and testing activity could also move the numbers. A 75 per cent fall is clinically striking — yet pinning the drop on a single programme intervention is not yet possible.[1]

On the uptake side the table is more concrete: in the first season 72 per cent of eligible pregnant women accepted the vaccine. RSV clusters between October and March; the shot is offered to women due to give birth in that window. Caroline Klint Johannesen says it is rewarding to see that work on paper can make a practical difference. Access is part of the same story as the outcome — if only ten thousand people had reached the vaccine, admissions would not have broken this sharply.[1]

The signal to watch

The signal to watch next RSV season is twofold: admission counts among infants aged 0 to 5 months and uptake among eligible pregnant women. Thea Kølsen Fischer says she expects at least as many eligible pregnant women to accept the vaccine next season, citing the safety profile and these early results; supported vaccination for adults over 60 at increased risk could pull total disease burden lower over time. Researchers say RSV is unlikely ever to disappear completely — but pushing severe disease below prior years' load is this season's real ward story.[1]