RSV and risk of asthma: In infants and young children, RSV can cause bronchiolitis, an infection of the small airways in the lungs, and infants hospitalized with RSV bronchiolitis are at increased risk of developing asthma: “About half of infants hospitalized with RSV infection will be diagnosed with asthma by age 7,” says lead author Dr. Avraham Beigelman, associate professor of pediatrics, allergist, and immunologist at Washington University. School of Medicine. “So we looked for approaches to prevent the development of asthma in these children. While azithromycin has anti-inflammatory effects in other airway diseases, such as cystic fibrosis, these effects made it a good candidate. Especially since previous data from preclinical studies and more limited clinical trials clearly suggested this effect”.
The antibiotic azithromycin has beneficial anti-inflammatory properties in certain chronic lung diseases, such as cystic fibrosis. The St. Louis researchers therefore looked at its potential in preventing wheezing in infants hospitalized with respiratory syncytial virus (RSV).
No effect of the antibiotic azithromycin on the risk of wheezing
The study, conducted among 200 infants hospitalized at St. Louis Children’s Hospital for RSV bronchiolitis to receive either oral azithromycin or a placebo for 2 weeks, however, shows no difference for this symptom, between infants treated and untreated. The analysis finds that:
- azithromycin does lower a marker of airway inflammation called IL-8: thus infants treated with azithromycin have lower levels of IL-8 in the nose compared to infants given a placebo, which confirms the anti-inflammatory effects of azithromycin;
- however, children treated with azithromycin have no significant reduction in the risk of wheezing;
- on the contrary: 47% of young patients who received azithromycin developed chronic wheezing vs 36% of the placebo group; treating these children with antibiotics may instead exacerbate this symptom.
What about other antibiotics? Although the study was not designed to analyze the effects of different combinations of antibiotics, the researchers point to evidence suggesting that azithromycin alone – in these children naïve to any other antibiotics – may increase the risk of wheezing. chronic.
Moreover, they conclude: “There may be an increased risk of recurrent wheezing with any use of antibiotics. While the study was not designed to test the effects of different antibiotics, this is an important message to convey to paediatricians, as antibiotic prescriptions remain frequent in this indication, despite the lack of clinical guidelines. Azithromycin and antibiotics in general have no benefit in preventing wheezing”.