VIRAL AND MYCOPLASMAL PNEUMONIA IN A PREPAID MEDICAL CARE GROUP DURING AN EIGHT-YEAR PERIOD1

Abstract

Foy, H. M. (School of Public Health and Community Medicine, Univ. of Washington, Seattle, Wash. 98195), M. K. Cooney, R. McMahan and J. T. Grayston. Viral and mycoplasmal pneumonia in a prepaid medical care group during an 8-year period. Am J Epidemiol 97: 93–102, 1973.—A study of pneumonia associated with infection with respiratory viruses and Mycoplasma pneumoniae was conducted in a large prepaid medical care group 1963–1971. Annual rates of pneumonia averaged 10 per 1000 with highest for children under the age of 5 (42 per 1000). Half of all pneumonia in children and 35% in adults was associated with viral or mycoplasmal infection. Annual rates for pneumonia associated with influenza A2 varied between 0 and 2 per 1000 with highest rates in those over 60 and in children 2–5 years old. During influenza epidemics the total pneumonia rates for adults, but not for children, rose. Pneumonia associated with influenza B infection was rare (0.2 per 1000 per year) and influenza B epidemics did not increase the overall pneumonia rates. Pneumonia related to parainfluenia infection (0.8 per 1000 per year) occurred fall through spring with the highest attack rates in children under five. Respiratory syncytial virus (1.2 per 1000 per year) was the most important agent in children under five. Epidemics of respiratory syncytial virus infection occurred in the spring, except for 1967 and 1971 when they occurred in the winter. Pneumonia associated with adenovirus was rare (0.4 per 1000) and occurred primarily in children under five without seasonal predilection. The endemic base rate for M. pneumoniae pneumonia was 1 per 1000 per year, but rates reached a high of 3 per 1000 in 1966–1967 and increased again in 1970–1971. School-age children had the highest attack rate.