Bivalent influenza vaccination with inactivated vaccines administered by nasal or oral route

Influenza vaccinations were performed either by administration of a bivalent A2 + B vaccine, or by successive application of monovalent B and A2 vaccines. During an influenza epidemic caused by an A2 strain, the following observations could be made: a) the best efficiency (no influenza cases) was recorded in adults and aged persons (over 65 years) irrespective of the vaccination scheme; b) in schoolchildren the best results (no influenza cases) were obtained in the lot having received monovalent A2 vaccine, and in the lot vaccinated nasally with monovalent B vaccine and 14 days later with monovalent A vaccine.