RS Virus Hospitalizations Drop After New Baby Vaccine in Netherlands

The rollout of a new preventative measure against respiratory syncytial virus (RSV) appears to be significantly reducing the number of infants requiring intensive care in the Netherlands. Hospitals are reporting a marked decrease in severe RSV cases this winter compared to previous years, a trend doctors attribute to the widespread administration of the RSV antibody injection, which became part of the national immunisation program in September 2025.

Roy Zuurbier, a pediatrician in training at Flevoziekenhuis, and researcher of RSV, explained the impact. “This season, we haven’t had to transfer a single baby to a pediatric intensive care unit due to lack of space, which is quite remarkable. During peak times in previous seasons, we sometimes had to transfer up to three children in a single week.”

The observed reduction in severe cases extends beyond intensive care admissions. Doctors at Flevoziekenhuis report fewer instances of needing to transfer patients to other hospitals due to capacity constraints. “Last year, there were frequent transfers to pediatric ICUs in other hospitals because it was too crowded here. A child would arrive in the emergency room, and there was no space available. We’ve experienced that significantly less this year,” a physician stated.

Sietse Nagelkerke, a pediatric infectious disease and immunologist, corroborates these observations. “The figures will only be finalized at the end of the RSV season, which isn’t quite over yet, but it’s clear here that the numbers are much lower than in recent years. You almost don’t see children who have received the injection being admitted here.”

Understanding RSV and its Impact on Infants

RSV is a common virus that typically circulates during the fall and winter months. While most children experience mild, cold-like symptoms – including a runny nose, cough, and sometimes fever – the virus can pose a serious threat to infants, particularly those under six months of age. Zuurbier explains, “Almost every child will get sick with it at some point. For most, it’s just a cold.” However, in vulnerable infants, RSV can lead to lower respiratory tract infections, causing inflammation and mucus buildup in the lungs, making breathing difficult. Severe cases may require intensive care, including mechanical ventilation.

Nagelkerke emphasizes the seriousness of severe RSV infections, noting that they often necessitate interventions like intubation, which, while life-saving, can be distressing for patients and carry potential side effects.

How the RSV Immunization Works

The new RSV preventative measure differs from traditional vaccination. It’s an immunization that provides babies with immediate protection through the administration of antibodies. “The antibodies protect the child against the virus for about six months. The child doesn’t have to produce its own antibodies and therefore doesn’t get sick from the immunization itself. The effect is almost immediate,” Zuurbier clarifies.

This approach also results in minimal side effects. “Perhaps some redness at the injection site, but fever is practically nonexistent.” The goal of the immunization isn’t to eliminate RSV from the community, but to prevent severe illness in vulnerable infants. “The immunization doesn’t remove the RS virus,” Nagelkerke states. “But it does ensure that far fewer children become seriously ill, and that helps enormously,” Zuurbier adds.

Current Observations and Future Outlook

Doctors are observing that the infants who are still being admitted with RSV often haven’t received the immunization, either because they are too young, contracted the virus before immunization, or their parents chose not to have them vaccinated. “Those children have similar admissions to last year and progress similarly,” Zuurbier notes.

Even among infants who do become ill despite receiving the immunization, the course of the illness appears milder. “In all these patients, we believe that without the immunization, the illness would likely have been much more severe. The protection isn’t complete, but it’s clearly present,” Nagelkerke explains.

The expectation is that the relatively mild RSV season will continue. “I think we’re already past the peak, which is normally around December. Now we’re seeing the flu emerge, but the number of RSV cases seems to be declining again,” Zuurbier says.

The success of the RSV immunization program in the Netherlands mirrors findings from other countries, including France and Luxembourg, where similar programs have led to an approximately 80% reduction in RSV-related hospitalizations. According to the RIVM, the antibody injection prevents about 80% of hospital admissions due to RSV in babies.