Does RSV Cause Asthma?

In the Northern Hemisphere it’s the season for respiratory illnesses. Children with RSV bronchiolitis usually wheeze. Often these same children go on to develop asthma. My hunch has been that RSV does not cause asthma, but that children born with a tendency to wheeze are more susceptible to both.

A study in the January 2000 Pediatrics supports this notion – and describes a simple blood test that can predict which children are most likely to go and develop asthma. The study looked at children sick enough to be hospitalized with RSV. Those who had a high eosinophil count had a 56% chance of developing asthma. The others with RSV had only a 22% chance.

While RSV and asthma certainly go together, even with severe RSV and a high eosinophil count, there is a good chance of avoiding asthma altogether.