• To improve the management and outcomes for infants hospitalised with Bronchiolitis through a controlled trial to assess the efficacy of a single dose of Azithromycin (30mg/kg) in 92 infants ≤18 months admitted to Royal Darwin Hospital and The Townsville Hospital.
  • To improve the clinical course of moderate to severe bronchiolitis
  • To reduce the risk of further respiratory illness within six months of this bronchiolitis episode
  • To profile the immunopathology of bronchiolitis in the presence and absence of co-existing respiratory infections.

Bronchiolitis remains the most common acute lower respiratory tract infection in infants. Bronchiolitis causes inflammation of the small airways, increasing mucous production and necrosis of epithelial tissue.

Bronchiolitis is a clinical diagnosis characterised by tachypnoea, wheeze and/or crepitations in infants following an upper respiratory illness. Most cases can be treated at home; however in some cases hospitalisation may be required for supportive therapy.

Northern Territory (NT) Indigenous infants present to hospital more often with severe bronchiolitis than non Indigenous infants. They are at greater risk of developing longer term respiratory problems including chronic suppurative lung disease or bronchiectasis. Bronchiolitis in NT Indigenous children is complicated by the known early colonisation of the nasopharynx by bacterial pathogens, notably Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae.

A class of antibiotics called macrolides, like Azithromycin, have been widely used in the NT for bronchiectasis for more than 10 years. Azithromycin has anti inflammatory and bacterial properties. It has a longer half life and better tissue penetration than other macrolides, thus requiring a much shorter treatment regime. Once weekly dosing has been shown to be sufficient for tissue effects lasting over a week.

Implications for policy and practice:

Any intervention that is efficacious in reducing the severity of bronchiolitis and or re-admission for bronchiolitis, in particular for Indigenous children, would be beneficial in both short and long term outcomes.

Our research has found: 

Although a single dose of azithromycin reduces carriage of bacteria, it is unlikely to be beneficial in reducing length of hospital stay, duration of supplemental oxygen required or readmissions to hospital in children hospitalised with bronchiolitis. It remains uncertain if an earlier and or longer duration of azithromycin improves clinical and microbiological outcomes children.

Chief Investigator:
Project Manager:
Contact information:
Project dates:


  • National Health and Medical Research Council (NHMRC)
  • Channel 7 Children’s Research Foundation
  • The Financial Markets Foundation for Children.
  • Townsville General Hospital.



  1. McCallum, G. B., Morris, P. S., Chatfield, M. D., Maclennan, C., White, A. V., Sloots, T. P., et al. (2013). A single dose of azithromycin does not improve clinical outcomes of children hospitalised with bronchiolitis: a randomised, placebo-controlled trial. PLoS One, 8(9), e74316.