Children born four months before peak flu season are more likely to develop childhood asthma compared to children born at any other time of the year, new research shows.

The study belongs to Tina Hartert of Vanderbilt University in Nashville, Tenn. and her colleagues and is to appear in the first issue for December of the American Journal of Respiratory and Critical Care Medicine, a publication of the American Thoracic Society.

The researchers analyzed the birth and medical records of more than 95,000 children and their mothers in Tennessee to see whether date of birth together with the peak in winter respiratory viruses posed a higher risk for developing early childhood asthma. The study found that kids born in early fall, about four months before the height of the winter cold and flu season, have a 30 percent higher risk of developing asthma compared to those born at any other time of year.

“We think this is because it puts them at high risk of getting a serious respiratory virus at a young age,” Hartert said, explaining the findings. The respiratory virus she is talking about is respiratory syncytial virus (RSV), which produces typical cold symptoms

She added that more study is needed to prove that preventing RSV could keep infants from developing asthma. “That is where we are now. We need to prove that preventing this infection prevents this lifelong chronic disease.” The easiest way to achieve this goal is to have a vaccine working on RVS but so far none exists. “It’s in the pipeline. We just don’t have one yet,” Hartert said.