Immunization against human and swine-like influenza A: serological response to two inactivated vaccines of different formulation.

The immunizing capacity and the tolerability of two purified vaccines containing the inactivated A/New Jersey/76 ( x 53 recombinant) swine-like strain were studied. A trivalent vaccine (A/New Jersey/76-300 I.U.; A/Victoria 3/75-300 I.U.; B/Hong Kong 5/75-300 I.U.) was administered to 31 subjects over 50 years of age. No side-effects were observed and it caused a good HI antibody response to A/New Jersey/76, fairly good for B strain and modest for A/Victoria 3/75. A monovalent vaccine (A/New Jersey/76-400 I.U.) was administered to 32 subjects in the age range from 16 to 43 years. HI antibodies occurred in 84% of the subjects, devoid of antibodies before vaccination. Younger subjects (between 16-20 years) generally developed fairly low antibody titres; one among them (16-year-old) had a temperature rise within 48 h after vaccination. The Authors expect that the X 53 recombinant with the surface antigens of the A/New Jersey/76 strain may be employed for the preparation of the inactivated vaccine to be used in an emergency situation and discuss the composition of the vaccine more adapt for the present epidemiological situation.