Measles (rubeola) infection in a hospital setting

stem (rubeola) hmpttat setting

infection

in a

Nancy Y. Watkins, R.N., M.P.H. Robert P. Smith, Jr., M.D. Donald L. St. Germain, M.D. Donald N. MacKay, M.D. Hanover,

New Hampshire

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. (AM J INFECT CONTROL 1987;15:201-6)

With the widespread use of measles (rubeola) immunization since 1963, the incidence of this viral illness has declined dramatically in the United States. However, the exclusive use of attenuated live virus measles vaccine, which produces long-lasting immunity, did not occur until 1968. As a result, a cohort of Americans born between the mid 1950s and late 1960s had little likelihood of exposure to natural measles and may have been immunized with a vaccine of limited efficacy. With the aging of this cohort, many of whom do not have measles immunity, measles outbreaks are now occurring in young adults in their late teens or early twenties, especially in institutional settings such as colleges.le3 This change in the epidemiologic pattern presents new challenges in the control of measles, and provides potential for the inadFrom the Departments of Pathology and Medicine, Dartmouth Medical School. Reprint requests: Dr. Robert P. Smith, Mary Hitchcock Memorial Hospital, Hanover, NH 03755.

vertent introduction of measles into hospitals. Unlike rubella, which has been responsible for several well-documented hospital outbreaks4e6 measles infection in the hospital setting has rarely been reported,‘! * and its consequences are unknown. Recently, Davis et a1.9 have emphasized the importance of transmission of measles in various medical settings. We herein report our experience with a cluster of measles cases at the Mary Hitchcock Memorial Hospital that involved four hospital employees and one patient and that occurred during a community measles epidemic. METftODSANDRESULTS Description of outbreak

and environment

Mary Hitchcock Memorial Hospital is a 4 1 lbed, tertiary care hospital, located in a small college community in New Hampshire. The hospital provides medical, surgical, pediatric, obstetric, and psychiatric services on a regional basis. Special programs include adult and premature infant intensive care units and a large 201

28 31 3 6 9 12 15 I6 21 24 27 30 3 6 9 12 I5 I8 21 24 27 30 2 5 MARCH

APRIL

MAY

JUNE

RASH ONSET (3-day periods1

Fig. 1. Measles Hitchcock

Memorial

cases, Dartmouth College and Mary Hospital, March through June 1984.

oncology program. The hospital is closely affiliated with a large ambulatory care facility, the Hitchcock Clinic, which averages 700 to 800 patient visits daily. The hospital also serves as the primary source of clinical experience for Dartmouth Medical School and provides clinical affiliations for nursing and other allied health students. There are approximately 2200 hospital employees including 187 house staff. Dartmouth College is located adjacent to the medical center. The college is primarily an undergraduate school with graduate programs in science, engineering, business, and medicine. There are approximately 4000 full-time students on campus. Contacts between Dartmouth students and medical center personnel are frequent within the hospital, the medical school, and the community at large. The college health service and infirmary are located adjacent to the hospital and share a number of hospital services. Outbreak

in the coBe@e tomnmity

Measles was initially introduced into the college community by a 27-year-old man, a graduate business student, who had the onset of a rash on April 3, 1984. He had recently traveled widely throughout the United States and the source of his infection was not established. He was hospitalized in the college infirmary from April 4 to April 8,1984, and seen in consultation by a staff physician from the Hitchcock Clinic.

A second generation of cases occurred berween April 13 and April 16 and included six additional graduate business students and the L%year-old son of the index patient (Fig. 1). At this time the State of New Hampshire Public Health Department began investigating the outbreak. Control efforts, including immunization, were focused on students at the graduate business school. Although medical center personnel were aware of the outbreak in the college and local community, no specific recommendations regarding screening or immunization of hospital personnel were issued, A voluntary measles immunization program was initiated by the Mary Hitchcock Hospital Employee Health Clinic. Employees were notified of vaccine availability through a periodic hospital newsletter. Eightysix employees were immunized between April 20 and May 16, 1984. The college outbreak appeared to be under control with a third generation of only four cases diagnosed between April 18 and April 30: two graduate students, an undergraduate student, and a 14-month-old child exposed to the son of the index patient. However, a fourth generation of cases began on May 8 and included 15 undergraduates, four medical center personnel, one hospitalized neurosurgical patient, and two other individuals from the local community. Outbreak

udtlah

the hoepital

The four cases of measles that developed in hospital personnel were diagnosed between May 16 and May 18. The diagnostic criteria used included: a generalized maculopapular rash for 3 or more days, fever of 38.3” C or higher, and cough, coryza, or conjunctivitis. All four cases were later confirmed by seroconversion of measles virus IgG by the enzyme-linked immunosorbent assay method (Measelisa ‘rest Kit; Whittaker M. A. Bioproducts, Walkersville, Md.). Personnel involved included a registered nurse assigned to an adult intensive care unit, a medical technologist, and two house staff physicians, one in medicine and one in surgery. They ranged in age from 27 to 33 years. Two of these individuals had documented histories of

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measles immunization in the early 1960s and one, according to a family member, had a history of measles during childhood. A 16-year-old female neurosurgical patient, who had never been immunized against measles, also developed the disease. She had arrived in the community about 24 hours before her hospitalization on May 1, 1984. After her admission she underwent corpus callosotomy surgery on May 3, 1984, spent the next 48 hours in the intensive care unit, and was then transferred to a general neurosurgical unit for further convalescence. A temperature elevation and coryza followed by a facial rash developed in this patient on May 15, 1984. The rash progressed to her chest and upper arms the next day, and a presumptive diagnosis of measles was made and was later confirmed serologitally. Although clustering of these hospital cases suggested a common exposure, further investigation could not identify a common source. Control

measures

By May 17,1984, the first three hospital cases had been diagnosed. Immediate control measures included respiratory isolation of hospitalized patients with measles (neurosurgical patient and one house staff physician who required hospitalization), identification of potentially susceptible patients who had face-to-face contact with diagnosed cases, and alerting of the Emergency Department and Employee Health Clinic to the possibility of additional employee or hospital-related cases. A group that included the chairman of the hospital infection control committee, the nurse epidemiologist, the medical director of the employee health clinic, a hospital administrator, and the assistant director of public affairs was formed to develop a plan to control the outbreak within the hospital. Advice was sought from the state public health department and the Centers for Disease Control (CDC). Additional control measures included the prompt immunization (within 72 hours) of exposed, susceptible patients and personnel, or provision of immune globulin for those who could not be safely immunized or whose exposure occurred 3 to 6 days earlier. Immuni-

Measles infection in a hospital setting

203

zation was also strongly recommended for all employees born during or after 1950 who were not certain of their immunity and all susceptible patients currently in the hospital, as well as those admitted during the next 14 days, especially if those patients required intensive care. Visitors who could not provide assurance of past measles infection or vaccination were not allowed in the hospital. Implementation of control measures: employees To rapidly provide employees with accurate information about the outbreak and need for immunization, a memo describing the outbreak and recommended control measures was widely circulated throughout the hospital. The names of the patients with measles were included (permission was obtained to do so) so that employees could recognize possible recent exposure. Because many employees could not be reached through this mechanism, information was also mailed to all employees and was included in press releases to the news media. An emergency supply of vaccine (trivalent measles-mumps-rubella) was obtained, and the hours of the Employee Health Clinic were expanded, including weekend coverage, to implement the emergency immunization program. Employees responded rapidly to the immunization program. More than 800 employees (which included 70% of those in the high-risk category) were immunized during the initial 3-day period. Many employees related a history of measles immunization but could not provide documentation. Although immunization was strongly recommended for these personnel, antibody titers were determined in those who were reluctant to be immunized. Antibody titers were also determined in pregnant employees. In all, 307 employees had antibody titers measured. Twelve of these employees were found to be susceptible to measles (Table 1) and were immunized. Two potentially susceptible employees who were exposed to a documented measles case more than 3 days before evaluation were not allowed to work for 2 weeks. Very few side effects were noted after vaccine

American

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Watkins et al.

INFEC~!IC)N

Table 1. Measles immunity in hospital employees screened during the outbreak at Mary Hitchcock Memorial Hospital, May and June, 1984 Susceptible

to measles

Susceptible

No. teeted

No.

%

1956 of after 1950-l 955 Before 1950 Unknown Total

114

5 5

1956

3

54

6 5 1 -Q

Before 1950 Total

307

12

38

of

Table 2. Prospective screening for measles immunity in new hospital employees at Mary Hitchcock Memorial Hospital, July 7 1984, to June 30, 1985

Year of birth

101

dourna! CONiROL

Year of birth

or after

1950-1955

0

No. tested

!Q measles

No.

%

9

1’

34

2

6

33 149

_I!

:j

11

7

82

.-

4

administration; a single individual developed a maculopapular rash with low-grade fever, another had transient arthralgias and knee swelling, and a third experienced a transient maculopapular rash.

Although control measures for employees were clearly focused and rapidly implemented, control measures for patients proved to be more complex and difficult to implement. A total of 36 patients had direct contact with an employee with measles and were thus considered exposed. All but six were born before 1950 and were considered to be immune. Five of the remaining six patients had a history of measles or prior immunization. The single exposed individual born after 1950 without such a history was immunosuppressed and was treated with immune serum globulin. Once the exposed patients had been identified, control efforts were focused on immunizing other susceptible p.atients in the appropriate age range within the hospital. A form that documented each patient’s measles history and immune status was developed, was placed on each patient’s chart, and formed the basis for identifying susceptible patients. Completion of this form was the responsibility of the attending physicians and nursing personnel on each unit. A retrospective review of this aspect of the control program indicated that fewer than 40% of the potentially susceptible patients had been assessed by use of the form. Exclusion of nonimmune visitors presented few problems in most areas of the hospital;

however, families of critically ill infants and children were often in a high-risk age group and frequently could provide no evidence of immunity. Nonimmune visitors were referred to their personal physician for immunization. After institution of these measures, no new cases developed among hospitalized patients or personnel.

To further investigate employee susceptibility to measles, a prospective screening program was initiated to determine antibody titers in all new hospital employees. During the 12-month period beginning July 1, 1984, 149 employees were tested and 11 (7%) were found to-have inadequate immunity (Table 2). These included two employees born between 1950 and 1955 and nine employees born after 1955. D The spread of a community measles epidemic into a hospital environment is an unusual event. Although transmission of measles in physicians’ offices and other medical settings has been reported,‘*” measles has not previously posed a recognized threat to infection eontrol in the hospital. However, the recent epidemiology of measles in this country favors hospital involvement during future measles outbreaks, particularly in hospitals with a col!ege or university affiliation. The primary-reason for this is the presence within such communities of a cohort of young adults who remain susceptible to measles. These individuals have not been exposed to measles, which was in decline

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during their childhood, and they began grade school before proof of immunization against measles was required. The prevalence of measles susceptibility in this age group may reach 15% to 20% and is responsible for the recent outbreaks on many college campuses.3 Although the CDC recommends including only those born between 1956 and 1968 in this highsusceptibility cohort, l2 two of our infected staff members were born before 1956, and the mean age of hospital employees with measles was 29.5 years. For this reason, we defined as a highrisk group all employees born after 1950 who did not have documentation of live attenuated measles immunization or physician-diagnosed measles as a child. This criterion seems particularly justified in light of the results of our retrospective and prospective screening programs in which approximately 5% of individuals born between 1950 and 1955 have had inadequate immunity to measles. Although defining a highrisk group as those born after 1956 may be appropriate for the general population, we believe that in a hospital setting, the level of measles immunity should be as close to 100% as possible. Chou et a1.13have recently reported a very low prevalence (1%) of measles serosusceptibility in individuals born after 1950 and employed in an urban Chicago hospital. This lower rate of seronegativity compared with the present findings is unlikely to be a result of the testing methods because the enzyme-linked immunosorbent assay used in our screening program has a falsenegative rate of <2%. I3 Thus the differences noted in susceptibility may be caused by the relatively small size of the populations sampled or by differences in the epidemiology of measles immunity in an urban versus a rural setting. Our experience highlights the difficulties presented by measles infection in hospital staff members. Three of our staff members had worked in the hospital during the prodromal period of their illness when measles is most contagious. Our greatest concern was the possible exposure of susceptible immunosuppressed, pregnant, or neonatal patients. Although there were many immunosuppressed or pregnant patients in our hospital at the time of the outbreak, only one susceptible immunosuppressed

Measles

infection

in a hospital

setting

205

patient was exposed. This patient was given immune globulin, and did not develop measles. The risk of serious illness after exposure to measles in immunosuppressed patients is not known. Giant cell pneumonia and a subacute encephalopathy have been reported in such patients.‘4-26 Both of these complications are associated with a high fatality rate. The risks of measles infection in pregnant women are also poorly documented. Although a congenital syndrome similar to that of rubella has not been reported, the possibility of increased fetal morbidity and mortality has been noted.27 In addition, infants born to susceptible mothers are at risk for serious measles infection2’, 28 Because of the highly contagious nature of measles and the uncertain but potentially severe consequences of measles infection in hospitalized patients, a number of recommendations for controlling nosocomial transmission can be made. Identification of all exposed patients is a first priority and within 72 hours after exposure, susceptible patients should be immunized. If immunization is contraindicated, as in patients who are pregnant or immunosuppressed, immune globulin may be given if exposure occurred within 6 days, recognizing that the efficacy of this therapy in such a setting is unproved.29 Simultaneously, all hospital employees must be alerted to report signs of possible measles infection and avoid patient contact if they are potentially susceptible to measles and experience prodromal symptoms. All employees in the high-risk age group without documented immunity to measles should be immunized or have a measles antibody titer determined. Because there is little risk in vaccinating previously immune individuals30 and because the determination of antibody titers is relatively costly and delays administration of vaccine, titer determinations probably should be reserved for documenting immunity in pregnant and immunocompromised individuals or those unwilling to be immunized. The legality of mandatory immunization in this setting is uncertain?’ In conclusion, we belive that the potential for spread of community measles outbreaks into the hospital setting is substantial and that hospitals should require documentation of measles

206

Watkins et al.

immunity in all employees born after 1950 who have significant patient contact, References 1. Krause PJ, Cherry JD, Deseda-Tous J, et al. Epidemic measles in young adults: clinical, epidemiologic, and serologic studies. Ann Intern Med 1979;90:873-6. 2. Centers for Disease Control. Measles-North America, 1984. MMWR 1985;34:366-70. 3. Centers for Disease Control. Measles on college campuses-united States, 1985. MMWR 1985;34:445-9. 4. Carne S, Dewhurst CJ, Hurley R. Rubella epidemic in a maternity unit. Br Med 3 1973;1:444-6. 5. McLaughlin MC, Gold LH. The New York rubella incident: a case for changing hospital policy regarding rubella testing and immunization. Am J Public Health 1979;79:287-9. 6. Polk BF, White JA, DeGirolami PC, Modlin JF. An outbreak of rubella among hospital personnel. N Engl J Med 1980;303:541-5. 7. Dales LG, Kizer KW. Measles transmission in medical facilities. West J Med 1985;142:415-6. 8. Centers for Disease Control. Measles-New Hampshire. MMWR 1984;33:549-59. 9. Davis RM, Orenstein WA, Frank JA Jr, et al. Transmission of measles in medical settings: 1980 through 1984. JAMA 1986;255:1295-8. 10. Remington PL, Hall WN, Davis IH, Herold A, Gunn R. Airborne transmission of measles in a physician’s office. JAMA 1985;253:1574-7. 11. Bloch AB, Orenstein WA, Ewing NM, et al. Measles outbreak in a pediatric practice: airborne transmission in an office setting. Pediatrics 1985;75:676-83. 12. Advisory Committee on Immunization Practices. Measles prevention. MMWR 1982;31:229-31. 13. Chou T, Weil D, Arnow PM. Prevalence of measles antibody in hospital personnel. Infect Control 1986;7: 309-l I. 14. Breitfeld V, Hashida Y, Sherman FE, Odagiri K, Yunis E. Fatal measles infection in children with leukemia. Lab Invest 1973;28:279-90. 15. Pullan CR, Noble TC, Scott DJ, Wisniewski K, Gardner PS. Atypical measles infections in leukemic children during immunosuppressive treatment. Br Med J 1976; 1:1562-5. 16. Measles encephalitis during immunosuppressive treatment. [Editorial]. Br Med J 1976;1:1552.

lNFFCTlON

CONTKX

17. Murphy JV, Yunis EJ. Encephalopathy iollowing measles infection in children with chronic illness. J Pediatr 1976;88:937-42. 18. Aicardi J, Goutieres F, Arsenio-Nunes ML, Lebon P. Acute measles encephalitis in children with immunosuppression. Pediatrics 1977;59:232-9 19. Wolinsky J, Swoveland P, Johnson KP, Baringer JR. Subacute measles encephalitis complicating Hodgkin’s disease in an adult. Ann Neurol 1977:1:452-7. 20. Smyth D, Tripp JH, Brett EM, et al. Atypical measles encephalitis in leukemic children in remission. Lnncet 1976;2:574. 21. Pederson FK, Schiotz PO, Valerins NH, Hertz H. Immunosuppressive measles encephalopathy. Acta Pediatr Stand 1978;67:109-12. 22. Agamanilis DP, Tan JS, Parker DL. immunosuppressive measles encephalitis in a patient with a renal transplant. Arch Neurol 1979;36:686-90. 23. Olding-Stenkvist E, Forsgren M, Henley D, et al. Measles encephalopathy during immunosuppression: failure of interferon treatment. Stand .I Infect Dis 1982; 14:1-4. 24. Simpson R, Eden 0. Possible interferon response in a child with measles encephalitis during immunosuppression. Stand J Infect Dis 1984;16:315-9. 25. Enders JF, McCarthy K, Mitus A, Cheatham WJ. Isolation of measles virus at autopsy in cases of giant cell pneumonia without rash. N Engl J Med 1959;261: 875-81. 26. Mitus A, Enders JF, Craig J, Holloway A. Persistence of measles virus and depression of antibody formation in patients with giant cell pneumonia after measles. N Engl J Med 1959;261:882-9. 27. Kohn JL. Measles in newborn infants (maternal infection). J Pediatr 1933;3:176-9. 28. Krugman S, Giles JP, Friedman H, Stone S. Studies on immunity to measles. J Pediatr 1965;66:471-8. 29. Kay HE, Rankin A. Immunoglobulin prophylaxis of measles in acute lymphoblastic leukemia. Lancet 1984; 1:901-2. 30. Centers for Disease Control. Measles prevention. MMWR 1978;26:427-37. 31. Grenstein WA, Haseltine PNR, LeGagnoux SJ, Portnoy B. Rubella vaccine and susceptible hospital employees: poor physician participation. JAMA 198 1; 245:71 l-3.