[The immunoprophylaxis of influenza among elderly persons]

Abstract

During three seasons at the period of 1992-1996 immunization of elderly persons, living in homes for old people, against influenza with inactivated influenza vaccine (IIV) was carried out. Altogether 856 persons were immunized intranasally, 581 persons constituting the control group. For comparison, 4,825 healthy young adults aged 18-24 years were immunized under similar conditions. The study revealed that the intranasal immunization of elderly persons with IIV, made in two administrations, was safe and stimulated sufficient humoral and secretory immunity: the level of seroconversions was 24.3-41.0% to type A(H1N1) influenza virus, 29.6-50.7% to type A(H3N2) influenza virus, 39.3-59.6% to type B influenza virus; the level of diagnostic IgA conversions was 31-38%. Immunization produced a pronounced prophylactic effect (the effectiveness index 1.6-1.7), as well as decreased the total mortality level by half. The tactics of the immunization of persons from high risk groups against influenza in medical practice is discussed.