Vaccines for preventing influenza in people with cystic fibrosis

Dharmaraj P, Smyth RL

Published Online:

August 10, 2011

People with cystic fibrosis have blocked airways which results in frequent airway infections. Infections with viral diseases like influenza ("the flu") can worsen lung damage. Doctors therefore often advise people with cystic fibrosis to be vaccinated against influenza every year. We searched for studies which compared different vaccines or compared vaccination to placebo. We were able to include four studies with 179 people in the review. Most (143) were under 16 years old. No study compared one vaccine to placebo. There were a high number of drop outs in two of the studies. Vaccination does result in an immune system response to the types of influenza used in the vaccine. However, this response may not result in protection against influenza infection or lung damage. There were a high number of adverse events, but none were serious or persistent. There is no evidence to show if regular influenza vaccine benefits people with cystic fibrosis.

Abstract (click to read)

Background:

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

Objectives:

To assess the effectiveness of influenza vaccination for people with cystic fibrosis.

Search strategy:

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: 14 March 2011.

Selection criteria:

All randomised and quasi-randomised trials (published or unpublished) comparing any influenza vaccine with a placebo or with another type of influenza vaccine.

Data collection and analysis:

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

Main results:

Four studies enrolling a total of 179 participants with cystic fibrosis (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.

Authors' conclusions:

There is currently no evidence from randomised studies that influenza vaccine given to people with cystic fibrosis 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.

This record should be cited as:

Dharmaraj P, Smyth RL. Vaccines for preventing influenza in people with cystic fibrosis. Cochrane Database of Systematic Reviews 2009, Issue 4. Art. No.: CD001753. DOI: 10.1002/14651858.CD001753.pub2

Assessed as up to date:

June 28, 2011

Health topics:

Cochrane Summaries

Independent high-quality evidence for health care decision making

Vaccines for preventing influenza in people with cystic fibrosis

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