The use of live attenuated influenza vaccine ts-1(E) in man.

Live temperature-sensitive influenza virus vaccines were tested in two volunteer experiments. The vaccine virus was originally derived from a temperature-sensitive mutant of influenza A/Great Lakes/1965 (H2N2) produced by chemical mutagenesis with 5-fluorouracil. The ts lesions of this strain were subsequently transferred (HI) antibody. Only 9 men (13%) were infected, presumably as a result of over-attenuation of the virus and/or insufficient titer of the inoculum. In the second experiment (1974), 20 young adults were given 0.5 ml per nostril of vaccine containing a recombinant of influenza A/Udorn/307/72 clone 24 (10(5.5) TCID50/ml) with an in vitro shutoff temperature of 38 degree C. Virus was shed by seven volunteers (maximum titer, 10(2.5)TCID50/ml). None of 21 isolates contained revertant wild type virus. Serum HI and antieuraminidase (NI) and nasal wash neutralizing antibody responses occurred in 11 (55%), 7 (35%), and 8 (40%) volunteers, respectively. Post-vaccination serum HI and NI and nasal neutralizing antibody geometric mean titers were 3.0, 9.4, and 1.7 lob2, respectively. Seven volunteers judged they had colds (symptom scores 4-32). Rhinitis and mild pharyngeal discomfort were the only consistent complaints and fever was absent. The findings in the latter trial will be compared with results of volunteer experiments with Udorn/72 ts-1-(E) in other laboratories and to studies with standard inactivated influenza vaccines given parenterally.