Origin and progress of the 1968-69 Hong Kong influenza epidemic.

The Hong Kong strain of influenza virus A2 may have originated in the mainland of China but this is not certain. It caused a very large epidemic in Hong Kong and spread rapidly to countries as far as India and the Northern Territory of Australia-as happened in the 1957 epidemic. Later its progress slowed down but epidemics occurred in many countries in the northern hemisphere in the winter of 1968-69.

WHO respiratory disease survey in children: a serological study.

This paper is a report on the first (serological) phase of a study organized by WHO in collaboration with the WHO International Reference Centre for Respiratory Virus Diseases other than Influenza in Bethesda, Md., USA, to define the viral etiology of severe respiratory infections in children, particularly in tropical areas. Paired sera from 528 children up to 5 years old admitted to hospital with severe respiratory illness of probable viral etiology were collected in 10 countries and sent frozen to the International Reference Centre, where standard complement-fixation tests were made for the following agents: parainfluenza virus types 1, 2 and 3, influenza virus types A and B, adenoviruses, respiratory syncytial virus, Mycoplasma pneumoniae, Coxiella burneti and psittacosis-ornithosis.

WHO collaborative study on the sero-epidemiology of rubella.

Under the auspices of WHO an investigation was made by 9 laboratories in different parts of the world on the distribution of rubella antibodies in girls and women of child-bearing age. In the first part of the study the objective was to determine the reliability and reproducibility of the tests employed. It was found that there were no significant differences in the variability of the titres obtained in different laboratories when the results were compared with those obtained by repeatedly testing the same sera in one laboratory.