Vaccines for preventing influenza in people with cystic fibrosis

Viral respiratory tract infections in people with cystic fibrosis (CF) have a deteriorating effect on their lung function and disease progression. Annual influenza vaccination is therefore commonly recommended for people with CF.

To assess the effectiveness of influenza vaccination for people with CF.

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register which comprises of references identified from comprehensive electronic database searches and handsearching of relevant journals and abstract books of conference proceedings. We also contacted the companies which market the influenza vaccines used in the trials to obtain further information about randomised controlled trials.Date of the most recent search of the Cystic Fibrosis Trials Register: 05 March 2009.

All randomised and quasi-randomised trials (published or unpublished) comparing any influenza vaccine with a placebo or with another type of influenza vaccine.

Two authors independently assessed study quality and extracted data. Additional information was obtained by contacting the investigators when it was indicated.

Four studies enrolling a total of 179 participants with CF (143 (80%) were children aged 1 to 16 years) were included in this review. There was no study comparing a vaccine to a placebo or a whole virus vaccine to a subunit or split virus vaccine. Two studies compared an intranasal applied live vaccine to an intramuscular inactivated vaccine and the other two studies compared a split virus to a subunit vaccine and a virosome to a subunit vaccine (all 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 out of 201 participants (24%) for the intranasal live vaccine to 13 out of 30 participants (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 study reported other clinically important benefits.

There is currently no evidence from randomised studies that influenza vaccine given to people with CF is of benefit to them. There remains a need for a well-constructed clinical study, that assesses the effectiveness of influenza vaccination on important clinical outcome measures.