Spread of influenzaviruses A/ENGLAND/42/72 AND A/Hong Kong/1/68

Seroconversion for A/England/42/72 (H3N2) virus occurred in a child in Calcutta in August 1971, one month after the virus was first isolated in India. During the following 5 months a small increase was observed in the geometric mean titres (GMT). In mid-1972 the virus was in Kathmandu, Nepal, where the children had a higher GMT than the adults. The GMT increased sharply during 1972 and early 1973 and this increase was accompanied by an increased number of hospital admissions for respiratory diseases. Among the people in the isolated village of Lang Tang (3 500 m elevation), the GMT and prevalence for both A/England/42/72 and A/Hong Kong/1/68 (H3N2) were less than 50% of the Kathmandu values.