Prevalence of measles antibodies in hospital personnel

Measles among adults, United States, 1985-1995

OBJECTIVE

To report the incidence and characteristics of adult measles cases in the United States and address the adequacy of current vaccination policies to eliminate measles transmission.

METHODS

Confirmed measles cases reported to the Centers for Disease Control and Prevention (CDC) from 1985 through 1995 were reviewed. Demographic data, exposure setting, and vaccination status of cases were analyzed and incidence rates calculated based on U.S. census data.

MAIN OUTCOME MEASURES

Age-specific incidence rates of measles and exposure setting.

RESULTS

Of the 75,204 reported measles cases of known age, 16,006 (21.3%) occurred in adults (persons > 19 years of age). The incidence in persons < 19 years of age (7.8/100,000) was 9.6 times that of all adults. Of 11,520 adult measles cases for whom vaccination status was reported, 8,055 (69.9%) indicated no prior receipt of measles vaccine. Exposure setting was unknown for the majority of adult measles cases (8,475, 52.9%); most frequently reported were college or school (2840, 17.7%), home (1443, 9.0%), or a medical setting (1286, 8.0%). International travel was associated with 289 (1.8%) adult cases. From 1993 to 1995, incidence rates in all age groups were at record low levels, with adults contributing 29.5% (467/1584) of reported cases.

CONCLUSION

Although adults accounted for a steadily increasing proportion of measles cases during the study period, incidence rates in all age groups have decreased. Most adults who had measles were susceptible because of lack of vaccination rather than vaccine failure. This analysis supports current strategies to ensure the immunity of school/college-aged populations, and health care workers.

Measles immunity among community hospital employees

OBJECTIVE

To define measles immunity rates among employees at 2 hospitals during a community outbreak in 1990.

DESIGN

Cohort survey using enzyme-linked immunosorbent assay (ELISA) and questionnaire.

SETTING

Two community hospitals.

PARTICIPANTS

Seventy-six percent of 2,060 employees.

RESULTS

Seven percent (115/1566) of participants lacked ELISA-defined measles immunity. Among employees whose ages were known, 14% (64/467) of those born after 1956 and 5% (50/1086) of those born before 1957 lacked serologic evidence of immunity. Fifty-eight percent of the susceptible persons had substantial patient contact. With ELISA results as the reference for immunity, the predictive value of an undocumented positive history of measles disease or vaccination was 95%; the predictive value of a negative history of both was 52%. Measles developed in 7 employees.

CONCLUSIONS

A substantial number of hospital employees lacked ELISA-defined measles immunity, including many who had patient contact or who had been born before 1957. Undocumented disease and vaccination histories were not adequate predictors of serologic status. This study supports the recommendations and suggestions of the Immunization Practices Advisory Committee that hospitals should require documented evidence of measles immunity from employees who have patient contact.

A creative method for determining the immunization status of a community hospital medical staff

During 1985 and 1986, 191 of the 212 (90%) medical staff members in active private practice, who were surveyed responded to a one-page report regarding the status of their immunity and immunization to important infectious illnesses. Response rates were improved by including the survey form with the hospital privilege-renewal form that was required to be returned to the medical staff office. Of the respondents 96% reported prior history of chickenpox and 95% reported prior immunization to tetanus; of the 42 who reported prior bacille Calmette-Guérin (BCG) vaccination, only 17 reported a positive tuberculin skin test. An additional 32 medical staff members had a history of a positive tuberculin skin test with no prior BCG vaccination. Only 2 (1%) reported prior history of hepatitis B, and only 15 (8%) reported hepatitis B vaccination begun or completed at the time of the survey. This survey allows targeting of infection control activities, such as implementation of the hepatitis B vaccine promotion program and serologic testing of those with a negative history of chickenpox, to be developed for the medical staff. It allows the hospital infection control team instant access to data that can be simply obtained and updated regularly when information is needed about the immunization status of selected medical staff members during an outbreak situation.

Measles (rubeola) infection in a hospital setting

Although acquisition of measles infection in medical facilities is well documented, hospital outbreaks have been rare. During a recent community measles epidemic, one patient and four employees of the Mary Hitchcock Memorial Hospital developed the disease. Two of the employees were born before 1956, the year recommended by the Centers for Disease Control as an appropriate cutoff year for routine measles vaccination. Screening of 456 hospital employees for measles immunity demonstrated a 5% incidence of susceptibility in 135 individuals born between 1950 and 1956. This experience demonstrates the significant potential for the spread of a community measles outbreak into the hospital setting. Because of the high transmissibility of this disease and its potentially serious consequences in hospitalized patients, we suggest that all hospital employees born after 1950 who have significant patient contact should have documented immunity against measles.