U.S. researchers concluded on Friday that babies that are born four months before the peak cold and flu season have a 30% higher risk of developing asthma, also suggesting that these common infections may trigger asthma. The study appears in the American Journal of Respiratory and Critical Care Medicine. Dr. Tina Hartert, director of the center for Asthma Research at Vanderbilt University, says it has been known for some time that children in the Northern Hemisphere born in the fall are at higher risk of developing asthma, but this study is the first to confirm this fact, by studying 95,000 medical records of infants and their mothers in the state of Tennessee.

The information that was found showed that babies with bronchiolitis, a lung infection caused by the respiratory syncytial virus or RSV, have a higher risk of developing asthma. Nevertheless, autumn babies were at the highest risk. Even if genetic risk factors predispose a child to develop asthma, environmental exposure such as winter viral infection may activate the asthma genes. Almost every child is infected with RSV early in life, with infections occurring most often between the ages of 3 and 6 months. Every time, the virus clears up without serious complications.

Dr. Hartert says that the task now is to prove that preventing such infections could keep infants from developing asthma. The easiest way to do that would be a vaccine but, unfortunately, none has been developed yet. However, a few classic remedies could include good hygiene and infection-control measures, such as staying away from sick children and washing their hands frequently. Vaccine makers GenVec, AstraZeneca’s MedImmune and others are working on RSV vaccines in order to prevent autumn babies from developing asthma in the future.