Understanding whether the prevention of RSV infection during infancy can reduce the risk of childhood asthma is key to designing successful and preventive strategies, preventing long-term childhood respiratory morbidity, and outlining healthcare policy measures.
Children who were not infected with respiratory syncytial virus (RSV) in their first year of life have a significantly reduced risk of developing childhood asthma.
In fact, not being infected with RSV during infancy was associated with a 26% lower risk of 5-year current asthma than being infected with RSV during infancy.
Data looking at the seasonal respiratory viral pathogen and major cause of morbidity and mortality in children younger than 12 months is supported by the INSPIRE study published in the Lancet in May.
Researchers of the study aimed to observe the association of early-life RSV in infants and the development of childhood asthma as it is unclear.
There have been several observational studies looking at the association between the two, but findings from those previous studies focusing on the exposure of early-life severe RSV infection can’t support a causal effect of the infection during infancy on the onset of childhood asthma.
Researchers note understanding whether the prevention of RSV infection during infancy — a crucial period of lung and immune development — can reduce the risk of childhood asthma is key to designing successful preventive strategies, preventing long-term childhood respiratory morbidity, and outlining healthcare policy measures.
Randomized controlled trials of RSV infection in the first year of life are unethical, researchers shared, and current agents for RSV vaccines decrease RSV severity but are unlikely to prevent the infection.
INSPIRE was conducted by researchers as a large, population-based, birth cohort of healthy infants with non-low birthweight born at term between June and December 2012, or between June and December 2013. Infants were recruited from 11 pediatric practices across middle Tennessee.
RSV infection status (no infection vs infection) was collected in the first year of life using passive and active surveillance through molecular and serological techniques. Children were then followed up for 5-year current asthma, which were analyzed in all participants who completed 5-year follow-up.
A child’s sex, race and ethnicity, any breastfeeding, day-care attendance during infancy, exposure to second-hand smoke in utero or during early infancy, and maternal asthma were taken into consideration also.
Out of the 1,946 eligible children enrolled in the study, 1,741 (89%) had available data to assess RSV infection status in the first year of life. There were 944 children with RSV during infancy out of the 1,741. Children with 5-year current asthma was lower than those without RSV infection during infancy than those with RSV infection during infancy.
The study suggested the estimated proportion of 5-year current asthma cases that could be prevented by avoiding RSV infection during infancy was 15%.
According to researchers, INSPIRE may be the first study specifically designed to test the that not being infected with RSV during infancy decreases the risk of childhood asthma. As mentioned, this statement is supported by previous studies having focused exclusively on early-life severe RSV infection.
It’s suggested to establish any casualties, the effect of interventions that prevent, delay, or decrease the severity of the initial RSV infection on childhood asthma will need to be studied.