in april-may 1980 a number of unrelated outbreaks of influenza-like diseases were registered in leningrad in an infant home ( 50 out of 68 children under observation , aged 3 months to 2 years , were affected ) and among the pupils of a boarding school ( 13 out of 50 adolescents under observation , aged 15-17 years , were affected ) .
C0021270
infant
C0008059
children