Six-year immunologic surveillance of schoolchildren vaccinated accordi
ng to different schedules in the town of Novgorod demonstrated the eff
icacy of overall vaccinations of children and young people with live a
ntiinfluenza vaccines in autumn and winter for 2 years. Then an interv
al of 3 years is to be made, followed by another 2-year revaccination
cycle, provided the same serologic subtypes of influenza A and B are s
till circulating.