Background and Significance
In the United States, wheezing and asthma are the leading causes of hospitalization among children under 5 years old, with approximately 30,000 admissions annually. About 2.2 million children aged 2-5 years visit emergency rooms each year for wheezing episodes. While some children outgrow wheezing over time, for others it is an early sign of asthma.
Previous studies found that children with frequent wheezing are more likely to carry potentially harmful bacteria in their throats, including Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae. This raised the question of whether antibiotics should be routinely used to treat wheezing in young children.
Study Design and Results
The AZ-SWED phase 3 clinical trial, led by the University of Arizona College of Medicine – Tucson, was conducted at eight pediatric emergency departments across the U.S. The study included 840 children aged 18-59 months who were randomly assigned to receive either azithromycin or a placebo for five days. Symptom improvement was assessed using the Asthma Flare-up Diary for Young Children (ADYC) score.
The trial was stopped early after an interim analysis showed that azithromycin did not significantly improve wheezing symptoms. ADYC scores did not differ between the antibiotic and placebo groups. Notably, the antibiotic was equally ineffective in children carrying the three specific types of bacteria.
Lead researcher Dr. Fernando Martinez, director of the U of A Asthma and Airway Disease Research Center, stated: 'We can say with a high degree of certainty that children who come to the doctor's office or the emergency room with a severe wheezing episode should not be given azithromycin or any antibiotic.'
Expert Insights and Recommendations
Dr. Martinez noted that experts have long advised against using antibiotics in these acute situations because wheezing is primarily caused by viruses. Yet approximately one-quarter of affected children still receive antibiotics in clinical practice. Overuse of antibiotics raises concerns about drug resistance and potential impact on children's normal immune development.
In the study, more than 86% of children seen in the emergency department tested positive for one or more respiratory viruses, with 72.5% infected with the common cold virus. Dr. Martinez emphasized the critical role of viral infections in wheezing and asthma:
- Using antibiotics when children are already sick with a virus produces no improvement.
- Even when bacteria are successfully eradicated, wheezing does not resolve, suggesting bacteria are not the direct cause.
- Bacteria may take advantage of the child's inappropriate immune response to the virus, rather than causing wheezing themselves.
Future Research Directions
Dr. Martinez's team is conducting follow-up studies to better understand the relationship between viruses and wheezing. They aim to explain why cold viruses cause only a runny nose in most children but can trigger severe wheezing and hospitalization in others. These findings could lead to more precise treatment strategies for wheezing in young children.