Background. Respiratory syncytial virus (RSV) has been recognized recently as an important adult pathogen. Methods. This randomized, double-blind, placebo-controlled study was designed to compare humoral responses to licensed trivalent influenza vaccine given concomitantly with 1 of 2 RSV vaccine formulations in persons ≥65 years old with cardiopulmonary disease. Hemagglutinin-inhibition assays and neutralization assays were used to measure levels of antibody to influenza and RSV, respectively. Subjects with respiratory illnesses during subsequent winters were tested for RSV and influenza by reverse-transcriptase polymerase chain reaction and serologic analysis. Results. Neither RSV vaccine formulation had an effect on the humoral response to influenza vaccination, and both RSV vaccines were well tolerated by 1169 participants. The immunogenicity of the nonadjuvanted vaccine was judged superior on the basis of mean postvaccination neutralizing antibody titers (12.5 vs. 12.1) and the percentage of subjects for whom ≥4-fold increases in neutralizing titer were observed when acute-phase and convalescent-phase serum samples were compared (168 [44%] of 383 vs. 129 [33%] of 400). In year 1, the percentage of illnesses due to RSV was 7% (36 of 492 illnesses) and that due to influenza was8%(40 of 492), compared with6%(11 of 189) due to RSV and 11% (20 of 189) due to influenza in year 2. The incidence of RSV infection was not significantly different in the RSV vaccine and placebo groups. Conclusions. Although the safety and immunogenicity data of these RSV vaccines are encouraging, low rates of infection make it challenging to design efficacy trials.
Bibliographical noteFunding Information:
Potential conflicts of interest: A.R.F. serves on the advisory board of Quidel, receives research grants from ADMA Biologics, and has been a consultant for sanofi pasteur, Merck, GlaxoSmithKline. E.E.W. receives research grants from Alnylam Biologics. V.M.-.P.S. was previously employed at sanofi pasteur. J.C. and E.Y. are currently employed by and own shares of sanofi pasteur. R.E. is a member of the sanofi pasteur speakers’ bureau. J.E.M. has been a consultant for and received research support and/or honoraria from sanofi pasteur, Merck, and GlaxoSmithKline. S.G., M.Z., K.L.N., E.A.F.S., P.F.W., F.G.H., G.J.G., and K.M.N. report no relevant conflicts of interest Presented in part: 6th International RSV Symposium, Marco Island, Florida, 25–28 October 2007. Financial support: sanofi pasteur.