Respiratory syncytial virus infection in the first year of life may increase the risk of asthma in children

"Over the past 60 years, scientists have repeatedly investigated the association between severe respiratory syncytial virus infection and asthma," said study author Dr. Tina Hartert of the Center for Environmental Science and Asthma at Vanderbilt University (USA). "However, we found this association is partly due to the shared genetics between severe respiratory syncytial virus infection and asthma. The solution in our study was to examine the association between respiratory syncytial virus infection and asthma by ensuring that all cases of respiratory syncytial virus infection will be recorded using molecular and serological techniques after the epidemic season."

According to experts, almost all children have been infected with respiratory syncytial virus by the age of 2. Respiratory syncytial virus is the leading cause of bronchiolitis, a lower respiratory tract infection accompanied by coughing and wheezing in infants and young children. Symptoms are mild in most children and usually last 1 week. However, respiratory syncytial virus infection can also lead to severe illness and death, especially in premature or young infants and those with chronic lung disease or congenital heart disease.

"Respiratory syncytial virus is the most common cause of hospitalization worldwide for respiratory problems in the first year of life," said study co-author Dr. Christian Rosas-Salazar, associate professor of pediatrics at Vanderbilt University.

Respiratory syncytial virus infection in the first year of life may increase the risk of asthma in children.

"In the study, healthy full-term infants who were not infected with respiratory syncytial virus in the first year of life were associated with a significantly reduced risk of childhood asthma, which affects about 8% of children in the United States. Our results suggest an age-dependent association between respiratory syncytial virus infection in childhood and childhood asthma," Rosas-Salazar added.

The team focused on the first year of life because they believe that: "When a child is infected with respiratory syncytial virus in the first year of life, while the lungs and immune system are still maturing, this may lead to some abnormalities that may later cause asthma."

The study included more than 1,900 healthy children aged 6 months or younger at the start of respiratory syncytial virus season (November to March in Tennessee, USA). Of these, about 54% were infected with respiratory syncytial virus in their first year of life, while the remaining 46% were not infected. The team then examined the children annually and assessed them for asthma at age 5.

Results showed that children who were not infected with respiratory syncytial virus in the first year of life had a 26% lower risk of developing asthma by age 5.

The scientists hope that: "The results of this study will promote long-term monitoring of respiratory status in children in ongoing clinical trials of respiratory syncytial virus prevention products, including vaccines and monoclonal antibodies."

"Demonstrating the efficacy of respiratory syncytial virus vaccine on childhood asthma will help increase public health interest and vaccine use," the scientists added./.