Azithromycin and Recurrent Wheeze in Children After Severe RSV Bronchiolitis

Respiratory syncytial virus. Coloured transmission electron micrograph (TEM) of a respiratory syncytial virus (RSV). This pneumovirus, a type of paramyxovirus, is a major cause of human respirat- ory tract infections in temperate climates, especially in winter. The virus consists of RNA (ribonucleic acid) genetic material enclosed in a protein coat, or capsid, within a phospholipid envelope. The envelope is covered in protein spikes, seen as the yellow lines around the edge of the virus. In adults, the virus only affects the upper respiratory tract, but in infants bronchiolitis (bronchiole inflammation) or bron- chopneumonia can result. Magnification unknown.
Research presented at AAAAI assessed the effectiveness of oral azithromycin in reducing recurrent wheeze in young children.

The following article is a part of conference coverage from the American Academy of Allergy, Asthma & Immunology Annual Meeting, being held in Phoenix, Arizona, from February 25 to 28, 2022. The team at Pulmonology Advisor will be reporting on the latest news and research conducted by leading experts in the field. Check back for more from the AAAAI 2022 Virtual Annual Meeting.

Although oral azithromycin therapy has been shown to attenuate airway inflammation during respiratory syncytial virus (RSV) bronchiolitis in children, the drug does not reduce the risk of recurrent wheeze, according to trial findings presented during the American Academy of Allergy, Asthma & Immunology (AAAAI) 2022 Annual Meeting, held in Phoenix, Arizona, February 25 to 28.

Researchers aimed to evaluate if azithromycin would reduce the occurrence of recurrent wheeze (RW) in young children. The APW-RSV II clinical trial ( Identifier: NCT02911935), a single-center, double-blind, placebo-controlled, study, included 200 children (1 to18 months of age) hospitalized due to RSV bronchiolitis with no comorbidities. Children were randomly placed into 2 cohorts: 1 cohort received 10 mg/kg azithromycin daily for 7 days followed by 5 mg/kg azithromycin daily for 7 days; the other cohort received placebo. The occurrence of RW, defined as a third episode of post-RSV wheeze during the following 2 to 4 years, was the primary outcome.

For patients treated with azithromycin vs placebo, the risk of RW did not differ (Adjusted Hazard Ratio [aHR] 1.45; 95% CI, 0.92-2.29; P =.11). The 2 cohorts also did not differ in any secondary outcomes: annualized number of days with albuterol use (rate-ratio, 1.22; 95% CI, 0.60-2.47); annualized number of days with respiratory symptoms (rate-ratio, 1.18; 95% CI, 0.86-1.62); number of subsequent antibiotic courses (rate-ratio, 0.98; 95% CI, 0.76-1.26); and number of subsequent oral corticosteroid courses (rate-ratio, 1.38; 95% CI, 0.73-2.60). Moreover, at the end of the study, lower levels of interleukin-8 (IL-8) were found in nasal wash fluids of patients treated with azithromycin vs those receiving placebo, (P =.003).

Researchers concluded that “Oral azithromycin therapy during acute severe RSV bronchiolitis in children reduced upper airway IL-8 levels, a marker of neutrophilic airway inflammation, but did not reduce the risk of RW over 2-4 years.”


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Beigelman A, Srinivasan M, Goss C, et al. Azithromycin to prevent recurrent wheeze following severe RSV bronchiolitis: the APW-RSV II clinical trial. Presented at: American Academy of Allergy, Asthma & Immunology (AAAAI) 2022 Annual Meeting; February 25–28, 2022; Phoenix, AZ. Abstract 456.