Recombinant WRL 105 strain live attenuated influenza vaccine. Immunogenicity, reactivity, and transmissibility.

The immunogenicity, reactivity, and transmissibility of recombinant WRL 105 (H3N2) (A/Okuda/57XA/Finland/4/74) strain live attenuated influenza virus vaccine were studied in adult male volunteers in a residential community in rural England. Thirteen volunteers received a single dose of 10(7.0) E.I.D.50 recombinant WRL 105 vaccine administered as nose drops, and twelve volunteers received placebo. Nine (82%) of eleven volunteers with initial antibody titres of less than or equal to 1/96 showed a significant antibody response to vaccination, but there was no evidence of transmission of vaccine virus to those who received placebo. The incidence and nature of reactions were similar in those who received vaccine and placebo. The vaccine was shown to confer protection against natural infection with a strain exhibition antigenic characteristics equivalent to those of A/Scotland/840/74.