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An unusual outbreak of measles occurred in 1982 in a pediatrician's office in Muskegon, Mich. Three children, who had arrived at the office 60 to 75 minutes after a child with measles had departed, developed measles. Using a model based on airborne transmission, it is estimated that the index patient was producing 144 units of infection (quanta) per minute while in the office. Characteristics such as coughing, increased warm air recirculation, and low relative humidity may have increased the likelihood of transmission. Adequate immunization of all patients and staff, respiratory isolation and prompt care of all suspected cases, and adequate fresh-air ventilation should decrease the risk of airborne transmission of measles in this setting. Airborne transmission may occur more often than previously suspected, a possibility that should be considered when evaluating current measles control strategies.

From December 10, 1982, to March 4, 1983, when influenza A (H3N2) viruses circulated in Michigan, outbreaks of influenza-like illness were identified in seven nursing homes in Genesee County; 272 (27%) of 1,018 residents were affected. Unvaccinated residents were more likely than vaccinated residents to become ill (risk ratio [RR], 2.6; 95% confidence interval [Cl], 1.8-3.6) and were subsequently more likely to be hospitalized (RR, 2.4; 95% Cl, 1.2-4.8), develop roentgenographically proven pneumonia (RR, 2.9; 95% Cl, 1.6-5.3), or die (RR, 5.6; 95% Cl, 1.2-9.1). Similar observations were made during investigations in six of the eight remaining nursing homes in Genesee County, in which 57 (12%) of 458 residents became ill sporadically. These findings suggest that influenza vaccine can reduce the incidence and severity of influenza virus infections among the elderly and chronically ill and underscore the importance of vaccination programs for those in nursing homes and in the general community.