A team of researchers released recommendations against the use of Pseudomonas aeruginosa vaccines in patients with cystic fibrosis.
The review resulted in patients with an average age of 7 years old, with all of the patients free of infection with P. aeruginosa at the start of the trials and having a lung function of at least 50% of their predicted age. These patients were followed from between 2 and 12 years and the following clinical outcomes were observed:
- after vaccination the risk of getting a chronic infection did not decrease and lung function was similar in both groups of cystic fibrosis patients
- One of the patients from the large trial died during the two year follow-up period
- In the small trial, one patient from each group had died after seven to eight years and by the end of the trial (10 to 12 years) six patients in each group had died.
- Patients who died were all chronically infected with P. aeruginosa
- There were 227 adverse events recorded by the investigators (four of which were classed as severe) in the vaccine group and 91 (one of which was classed as severe) in the placebo group.
- There were 91 adverse events recorded by the investigators (one of which were classed as severe) in the placebo group
- There was a rise in antibodies against P. aeruginosa with no change in the placebo group.
When discussing the results of the study, the investigators wrote, “The trial data we reviewed did not suggest that the vaccines tested for preventing infection against P. aeruginosa were effective. Effective vaccines have been developed against other bacteria, e.g. Haemophilus influenzae, Neisseria meningitidis and Streptococcus pneumoniae, and there is clearly a need for additional basic research to further increase our understanding of those elements of the immune response to P. aeruginosa that could potentially have a protective effect in patients with CF. Beneficial alterations in immune responses have been seen in animal experiments (Johansen 1995) and should be further evaluated (Moser 2000).”