Fever, chills, and other symptoms characteristic of influenza appeared in 18 out of 23 (78%) unvaccinated volunteers about 38 hours after the nasopharynx was sprayed with nasopharyngeal secretions containing living virus from three influenza patients. The virus was influenza A/Valley Forge/57, which was antigenically similar to the Far East strain. When the same material was administered to 32 volunteers who had been vaccinated against influenza A/Japan/305/ 57, the cases of febrile illness numbered 14 (44%). The vaccination and the challenge inoculation both induced a hemagglutination inhibition antibody response. Influenza virus was recovered from 14 (41%) of ill volunteers. The vaccination therefore gave significant though incomplete protection against Asian influenza.
Bell JA, Ward TG, Kapikian AZ, Shelokov A, Reichelderfer TE, Huebner RJ. ARTIFICIALLY INDUCED ASIAN INFLUENZA IN VACCINATED AND UNVACCINATED VOLUNTEERS. JAMA. 1957;165(11):1366-1373. doi:10.1001/jama.1957.02980290006002