Background: Viral respiratory tract infections in patients with cystic fibrosis have a deteriorating effect on their lung function and disease progression. Annual influenza vaccination is therefore commonly recommended for patients with cystic fibrosis.
Objectives: To assess the effectiveness of influenza vaccination for patients with cystic fibrosis.
Search strategy: We have used the Cochrane Cystic Fibrosis and Genetic Disorders Group specialist trials register which comprises references identified from comprehensive electronic database searches, hand searching relevant journals and abstract books of conference proceedings and communication to the drug companies marketing influenza vaccines.
Selection criteria: All randomised and pseudorandomised trials (published or unpublished) comparing any influenza vaccine with a placebo or with another type of influenza vaccine.
Data collection and analysis: Both reviewers independently assessed trial quality and extracted data. Additional information were obtained by contacting the investigators when it was indicated.
Main results: Three trials enrolling a total of 115 patients with cystic fibrosis (76 (66%) were children aged one to 13 years) were included in this review. There was no study comparing a vaccine to a placebo or a whole virus vaccine to a sub unit or split virus vaccine. Two studies compared an intranasal applied live vaccine to an intramuscular inactivated vaccine and one study compared a split virus to a sub unit vaccine (both intramuscular). The incidence of all reported adverse events was high depending on the type of influenza vaccine. The total adverse event rate ranged from 48/201 (24%) for the intranasal live vaccine to 13/30 (43%) for the split virus vaccine. With the limitation of a statistical low power there was no significant difference between the study vaccinations. None of the events were severe. All study influenza vaccinations generated a satisfactory serological antibody response. No trial reported other clinically important benefits.
Reviewer's conclusions: There is currently no evidence from randomised studies that influenza vaccine given to patients with cystic fibrosis is of benefit to them. There is a need for a well constructed clinical study, that assesses the effectiveness of influenza vaccination on important clinical outcome measures.