Measles and Healthcare Workers

Abstract

This issue of Infection Control and Hospital Epidemiology contains three articles that help answer several fundamental questions in the prevention of measles among healthcare workers: the magnitude of measles susceptibilityl,2; the effect of vaccination on susceptibility levels2; and the cost of ensuring that healthcare workers are protected against measles.3 Measles among healthcare workers accounts for a small but important proportion of reported cases. Healthcare workers with measles often serve to amplify outbreaks in medical settings because of transmission to patients and other healthcare workers, and may serve as a source of infection for family members and other contacts. The National Immunization Program collects information on the most likely setting of transmission of reported measles cases. From 1985 through 1991, medical facilities were identified as the most likely setting of transmission for 2,997 reported measles cases4 (4% of cases; CDC, unpublished data). Almost half of these medical setting cases were acquired in hospital inpatient units. The remainder were almost divided equally between physician's offices and hospital emergency departments. Adults > 18 years of age accounted for 1,234 (41%) of medical setting measles cases. Only colleges and household contacts accounted for more measles cases among adults. Based on case investigations conducted by state health departments, of all adults who acquired measles in medical settings, 170 (14%) were patients. A few were visitors or persons for whom an occupation was unknown. But 795 (64%) of these adults were healthcare workers. Not surprisingly, the largest groups of healthcare workers who acquired measles at work were nurses (29%) and physicians (15%). Other occupational groups were represented, including laboratory and radiology technicians (11%), clerks (11%), nursing assistants (4%), and medical and nursing students (4%). Cases of measles have been reported from virtually all occupations that provide healthcare or ancillary support-maintenance and housekeepers, respiratory therapists, emergency medical technicians and paramedics, security guards, dietitians, pharmacists, electrocardiography technicians, administrators, volunteers, and translators. In many instances, the patient contact that led to measles in the healthcare worker did not qualify as direct patient care, a fact that illustrates the extreme transmissibility of measles virus. Only 16% of healthcare workers with measles were able to document receipt of a dose of measles vaccine, and virtually none had received two doses. More than half were routinely eligible for vaccination (ie, born after 1956, without medical contraindication or exemption to vaccination). Two hundred thirty healthcare workers reported with measles (29%) were born before 1957, a group that Advisory Committee on Immunization Practices (ACIP) recommendations state should not be considered routinely eligible for measles vaccination.5 The 1957 Rule, as it is sometimes called, was first included in an ACIP measles statement in 1978. Prior to this, the recommendation had been more generic-that adults usually were