[Skip to Content]
[Skip to Content Landing]
Original Contributions
November 30, 1964

Outbreak of Influenza A2 Among Immunized Children

Author Affiliations

From the Virology Laboratory and Department of Pediatrics, Bowman Gray School of Medicine, Winston-Salem, NC. Dr. Moffet is now at the Children's Memorial Hospital, Chicago, and Dr. Cramblett is now at the Children's Hospital, Columbus, Ohio.

JAMA. 1964;190(9):806-810. doi:10.1001/jama.1964.03070220012002

An outbreak of influenza A2 occurred in 1963 in a children's home five months after half the population had been given two injections of commercial polyvalent vaccine. About 90% of the children who had received the influenza vaccine before the outbreak had an antibody titer of 1:80 or higher against the 1962 strain of influenza A2. The frequency of clinical illnesses for immunized children was slightly but significantly less than for the nonimmunized children. The 1963 outbreak of influenza A2 had a lower infectivity rate, occurred over a longer period of time, and was associated with fewer severe illnesses than the outbreak of influenza B which occurred in the same home in 1962, when no child had received influenza vaccine.