An outbreak of influenza A/Taiwan/1/86 (H1N1) infections at a naval base and its association with airplane travel.

In late October 1986, an outbreak of influenza-like illness was detected at the Naval Air Station in Key West, Florida. Between October 10 and November 7, 1986, 60 active duty personnel reported experiencing a respiratory illness characterized by fever, cough, sore throat, and myalgia. Influenza A/Taiwan/1/86 (H1N1) virus was recovered from three symptomatic patients. Forty-one (68%) of 60 case-patients belonged to a 114-person squadron that had traveled to Puerto Rico for a temporary assignment from October 17-28, 1986. Among squadron members, the attack rate for persons previously vaccinated with the 1986-1987 trivalent influenza vaccine and for those unvaccinated was the same (37%). Transmission of infection among squadron personnel appeared to have commenced in Key West and continued in a barracks in Puerto Rico and aboard two DC-9 aircraft that transported the squadron back to Key West on October 28. There was no evidence that the outbreak spread to the surrounding civilian communities in Puerto Rico or Key West. This was the first reported outbreak of respiratory illness due to influenza A/Taiwan/1/86 (H1N1) in the continental United States in the 1986-1987 influenza season.

Class-specific antibody responses in school children vaccinated with an A/Brazil/11/78 (H1N1)-like recombinant influenza virus prepared from the A/Leningrad/134/57 paediatric cold-adapted donor strain.

Forty-three school children from 8 to 11 years old were vaccinated intranasally with two doses of a paediatric attenuated influenza vaccine developed by reassortment between cold-adapted A/Leningrad/134/57(H2N2) and an A/Brazil/11/78(H1N1)-like strain. Two vaccine doses were administered 1 month apart in a randomized, blind, placebo-controlled study. Although the first vaccine dose had a low infectivity titre, overall 65% of children who received two doses of vaccine showed serological evidence of infection by HI tests. Serum IgA antibody responses against the vaccine strain were detected in nearly 50% of the vaccines and serum IgG antibody responses were detected in approximately equal to 40% by an enzyme immunoassay.