Safety and immunogenicity of Pseudomonas aeruginosa conjugate A vaccine in cystic fibrosis.

To assess the safety and immunogenicity of a Pseudomonas aeruginosa octavalent O-polysaccharide-toxin A conjugate vaccine, 22 patients (mean age 7 years) with cystic fibrosis who had no history of colonisation with P aeruginosa were immunised with the vaccine. Adverse reactions were mild and self-limiting. IgG antibody concentrations to all vaccine antigens were significantly raised after vaccination and remained so for 12 months. Immunisation produced opsonic and toxin A neutralising antibodies. A booster dose given at 12 months led to an anamnestic response. There was no significant change in clinical status after vaccination. Further work to assess efficacy in patients with cystic fibrosis can now be considered since our findings support the safety and immunogenicity of the vaccine.