Sequential annual administration of purified fusion protein vaccine against respiratory syncytial virus in children with cystic fibrosis.

BACKGROUND

We recently showed the clinical benefit of the PFP-2 vaccine for respiratory syncytial virus (RSV) for children with cystic fibrosis (CF).

OBJECTIVE

To determine the safety and immunogenicity of yearly sequential administration of the PFP-2 vaccine in CF children.

STUDY DESIGN

Twenty-nine of the 34 CF children who participated in the previous study were enrolled in this open label vaccine study. All of the CF children ages 2.6 to 8.9 years received the PFP-2 vaccine, the PFP/PFP group received the PFP-2 vaccine in 1993 and 1994 and the saline/PFP group received the vaccine for the first time in 1994. At entry demographic data and measurements of lung function and nutrition were collected. Microneutralization test, enzyme-linked immunosorbent assay to F protein and Western blot assay were performed on plasma drawn before and 4 weeks after vaccination and at the end of the RSV season. During the study weekly telephone calls were made and acute respiratory illnesses were evaluated.

RESULTS

Baseline measurements were similar between groups. Systemic and local vaccine reactions were mild and similar for both groups. A 4-fold or greater neutralizing antibody rise to RSV occurred in 4 of 14 (28.6%) and 9 of 14 (64.3%) in PFP/PFP and saline/PFP groups (P = 0.13), respectively. Four children in the PFP/PFP group and 7 in the saline/PFP group were infected with RSV. A reduction in lower respiratory illnesses (1.0 vs. 2.0), antibiotic courses (2.5 vs. 5.6) and days of illnesses (37.3 vs. 93.1) was observed in the PFP/PFP vaccinees infected with RSV compared with the saline/PFP group (t test; P < or = 0.05). One death occurred in the PFP/PFP group; the cause of death was consistent with septic shock and unrelated to vaccination or RSV infection.

CONCLUSION

Sequential annual PFP-2 vaccination was safe and not associated with exaggerated respiratory disease.