A comparison of hospital policies for measles, mumps, and rubella infection control in Los Angeles County, 1989 and 1992

A comparison of hospital policies for measles, mumps, and rubella infection control in Los Angeles County, 1989 and 1992 Donnell P. Ewert, MPH* Diana Garcia, MPH¢ Julia George, DrPH Laurene Mascola, MD, MPH Los Angeles, California

Background: A survey was conducted in 1992 in Los Angeles County, California, to assess

changes since an earlier survey in 1989 in the numbers of acute care hospitals that had established policies on measles, mumps, and rubella infection control and the extent t o which these policies were implemented. Methods: A questionnaire inquiring about measles, mumps, and rubella infection control was sent to ICPs of 133 acute care hospitals in Los Angeles County. The results were compared with those of a similar survey conducted in 1989. The increase in the number of hospitals with such policies between 1989 and 1992 was analyzed. Results: In 1989, 29 (28%), 9 (9%), and 65 (64%) of the 102 respondent hospitals had measles, mumps, and rubella infection control policies, respectively. Larger proportions of the 95 respondent hospitals in 1992 had measles (56, 59%), mumps (15, 16%), and rubella (69, 73%) infection control policies. Conclusions: The number of hospitals with infection control policies for measles, mumps, and rubella increased from 1989 to 1992. Efficiency and scope of such policies varied, however, and could be improved by making the policies mandatory, requiring written documentation of employee immunity, and extending policies to cover all employees. The most dramatic increase was in the number of hospitals with infection control policies for measles; this increase may have been caused by the 1987 to 1989 measles epidemic in Los Angeles County, by increased awareness of the Immunization Practices Advisory Committee recommendations, or by increased sensitivity to the issue of infection control triggered by the 1989 survey. (AJIC AM J INFECTCONTROL1995;23:369-72) Of t h e 2 7 , 7 8 6 m e a s l e s c a s e s r e p o r t e d n a t i o n a l l y to t h e C e n t e r s f o r D i s e a s e C o n t r o l a n d P r e v e n t i o n in 1990, 1163 (4%) w e r e t r a n s m i t t e d in m e d i c a l From Acute Communicable Disease Control, Los Angeles County Department of Health Services, Los Angeles. *Currently at Communicable Disease Division, Indiana State Department of Health, Indianapolis. ~:Currently at Los Angeles County West Vector Control District, Culver City. Reprint requests: Laurene Mascola, MD, MPH, Chief, Acute Communicable Disease Control, Los Angeles County Department of Health Services, 313 N. Figueroa, Rm. 231, Los Angeles, CA 90012. Copyright © 1995 by the Association for Professionals in Infection Control and Epidemiology, Inc. 0196-6553/95 $3.00 + 0

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c a r e settings. Of 521 a d u l t s w h o c o n t r a c t e d m e a s l e s in m e d i c a l c a r e settings, 314 (60%) w e r e health care workers (HCWs). Nurses, physicians, l a b o r a t o r y a n d r a d i o l o g y staff, a n d c l e r i c a l p e r s o n n e l w e r e the t y p e s o f H C W m o s t o f t e n affected. 1 A l t h o u g h h o s p i t a l e m p l o y e e s a c c o u n t f o r o n l y a s m a l l p e r c e n t a g e of total m e a s l e s c a s e s r e p o r t e d , s t u d i e s h a v e d e m o n s t r a t e d t h a t the i m p a c t of i n f e c t i o n o n b o t h H C W s a n d t h e i r c o m m u n i t i e s is high. I n f e c t e d h o s p i t a l e m p l o y e e s m i s s d a y s o f w o r k , a f f e c t i n g h o s p i t a l efficiency, a n d also h a v e h i g h r a t e s o f a d u l t m e a s l e s - r e l a t e d c o m p l i c a t i o n s a n d h o s p i t a l i z a t i o n s . 2-4 The impact of measles, mumps, and rubella n o s o c o m i a l t r a n s m i s s i o n in h o s p i t a l s w i t h o u t est a b l i s h e d o r e n f o r c e d i m m u n i t y p o l i c i e s w a s illust r a t e d in the 1983 to 1985 r u b e l l a o u t b r e a k in a

369

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Table

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E w e r t et al.

1. Characteristics of hospital infection control policies for measles, mumps, and rubella: LAC, 1989

and 1992 Measles 1989 (N = 29)

Mumps

1992 (N = 56)

1989 (N = 9)

Rubella 1992 (N = 15)

1989 (N = 65)

1992" (N = 69)

Measure

No.

%

No.

%

No.

%

No.

%

No.

%

No.

%

Mandatory policy Accept only written documentation Accept oral and written documentation (seropositivity, date of birth, history) Covers all employees, residents, students, and volunteers

17 12

59 41

36 21

64 38

5 5

56 56

6 4

40 27

46 48

71 74

54 40

78 58

17

59

35

63

4

44

11

73

17

26

29

42

4

14

4

7

0

0

2

13

0

0

4

11 *

*Data availableonly for 36 hospitals.

South Bronx hospital. Members of the medical staff, including four physicians, five nurses, two laboratory workers, two clerical workers, and one radiology technician, were infected by factory workers who sought care at the hospital's dermatology clinic. 5 Although New York state law required rubella screening and vaccination of all hospital employees, the law was not effectively implemented and enforced. To prevent nosocomial measles transmission, the Immunization'Practices Advisory Committee (ACIP) recommended in 1989 that all HCWs, residents, students, and volunteers without serologic confirmation of immunity, written documentation of immunization against measles, or documentation of birth date before January 1957 be vaccinated. 2 Since 1989, a second dose of live vaccine has been recommended for all hospital workers born after January 1957. Persons born before January 1957 are considered to be immune to both measles and mumps (because of probable childhood acquisition); however, in 1991 ACIP further suggested that, in the absence of documentation of immunity, medical facilities require at least one dose of measles vaccine for persons born before 1957. 2, 6 The potential for nosocomial measles transmission to susceptible HCWs is greatest during measles outbreaks. From 1987 to 1989, Los Angeles County (LAC) faced the first 3 years of a 5-year measles outbreak that resulted in a total of 1834 cases; of these cases, 74 (4%) were among adults employed in LAC acute care hospitals.

About one third of the affected HCWs worked in areas that were not designated as high risk, and about one half were born before 1957. These factors suggest that implementation of the 1989 ACIP recommendations might not have prevented some of these nosocomial infections; the more comprehensive 1991 recommendations would perhaps have been more effective in preventing transmission of infection. A 1989 survey conducted by the LAC Department of Health Services Acute Communicable Disease Control Unit surveyed ICPs of LAC acute care hospitals to ascertain the proportion of institutions with infection control policies for measles and rubella and the scope of the policies that did exist. The unit also investigated hospital employee measles cases that occurred between 1987 and 1989. Questionnaires were sent to 145 ICPs, with second copies of the questionnaire later sent to nonrespondents. The researchers found that only 17 of the 102 LAC hospitals that responded to the survey (16.7%) had mandatory measles policies, and that 34 of the HCWs who contracted measles (46%) were working in hospitals without infection control policies. 3 At the time of the 1989 survey, the ACIP screening and vaccination recommendations for hospital employees had just recently had been updated and published, a The ACIP recommendations were updated again in 1991. 6 In 1992, another hospital survey was conducted by the LAC Department of Health Services Acute Communicable Disease Control Unit to ascertain whether a

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E w e r t et al.

T a b l e 2. Characteristics of hospitals' mandatory policies for measles, mumps, and rubella infection control: LAC, 1992 Measles (N = 36)

Mumps (N

=

6)

Rubella (N

=

54)

Measure

No.

%

No.

%

No.

%

Accept only written documentation Covers all employees, residents, students, and volunteers

17

47

3

50

36

67

4

11

2

33

4

7

T a b l e 3. Percentage of hospitals with policies for measles, mumps, and rubella vaccination, by hospital characteristics: LAC, 1992

With policy Hospital characteristics Hospital size Measles < 200 beds _>200 beds Mumps < 200 beds _>200 beds Rubella < 200 beds _>200 beds No. of ICPs Measles One part-time More than one part-time Mumps One part-time More than one part-time Rubella One part-time More than one part-time

N

No,

%

48 47

35 21

73 45

48 47

10 5

21 11

48 47

37 32

77 68

42 53

18 38

43 72

42 53

3 12

7 23

42 53

27 42

64 79

OR

95% CI

3.3

1.3-8.6

2.2

0.6-8.7

1.6

0.6-4.3

3.4

1.3-8.7

3.8

0.9-22.3

2.1

1.0-1.6

OR, Odds ratio; CI, confidenceinterval (of odds ratio).

larger proportion of hospitals had established infection control policies for measles, mumps, and rubella in 1992 than in 1989.

the first mailing. Odds ratios and 95% confidence limits were calculated to determine whether hospital size and number of ICPs were associated with the existence of infection control policies.

METHODS

In June 1992, a questionnaire regarding hospital policies addressing infection control for measles, mumps, and rubella was sent to ICPs of 133 operational acute care hospitals in LAC. The questionnaire, which was similar in content to the one used in 1989, included questions about hospital immunity policies for employees and about criteria for verification of employee immunity. In August 1992, a reminder and a second questionnaire were sent to ICPs who had not responded to

RESULTS

Ninety-five of the 133 hospitals surveyed in 1992 (71%) responded to the questionnaire. Of these 95 respondent hospitals, 56 (59%) had measles policies, 15 (16%) had mumps policies, and 69 (73%) had rubella policies. In comparison, of the 102 hospitals that had responded to the 1989 questionnaire, 29 (28%) had noted measles policies, 9 (9%) had noted mumps policies, and 65 (64%) had noted rubella policies (Table 1). 3

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Although a larger proportion of hospitals had mandatory measles, mumps, and rubella policies in 1992 than in 1989, the only statistically significant positive increase seen was in the number of hospitals with measles policies; this number had doubled since 1989 (p < 0.0001). Policies for m u m p s and rubella in hospitals had also increased by 1992, but the increases were not statistically significant (p = 0.07 and p = 0.08, respectively). Of the 36 hospitals with mandatory policies for measles in effect in 1992, just 17 (47%) required written documentation of immunity, and only four (11%) extended these policies to affect all employees, residents, students, and volunteers (Table 2). Of the six hospitals with policies for mumps, only three (50%) required written documentation, and only two (33%) applied the policy to all employee categories (Table 2). Of the 54 hospitals with rubella policies, 36 (67%) required written documentation, but only four (7%) applied the policy to all employee categories (Table 2). The characteristics of smaller hospital size and the employment of one or more full-time ICPs were positively associated with the presence policies for measles, mumps, and rubella immunity. The associations were statistically significant, however, only for rubella policies (Table 3). DISCUSSION

Overall, the number of hospitals in LAC with policies for measles, mumps, and rubella in 1992 increased compared with the number in 1989. The greatest increase seen was in the number of hospitals with policies for measles. Despite the increases, the efficiency and scope of the policies in effect in 1992 could be improved: only about half of the hospitals surveyed had policies requiring written documentation of immunity to all three infections measles, mumps, and rubella, and fewer than a third of the hospitals with mandatory policies extended their policies to cover all hospital employees, residents, students, and volunteers. The increase between 1989 and 1992 in the number of hospitals with policies for measles, mumps, and rubella infection control could be caused by a variety of factors. These include

response to the LAC measles epidemic of 1987 to 1989, increased compliance with the ACIP recommendations, and increased awareness of the need for immunity policies as a result of the 1989 survey. Limitations of this study include the possibility of response bias. Of the 133 hospitals targeted for the survey, 38 (29%) did not respond to the questionnaire; five of the nonresponding hospitals were major medical centers. The numbers of hospitals responding to the 1989 and 1992 questionnaires were similar, however, so statistical comparisons between the two sets of responses are considered valid. Maintenance of high levels of immunity among all hospital employees, regardless of age and degree of patient contact, has been shown to impede nosocomial transmission of measles, mumps, and rubella. Prevention of infections a m o n g employees decreases costs of hospitalization and loss of productivity. To prevent potential measles, mumps, and rubella cases and to safeguard both employees and patients during subsequent outbreaks, hospitals should establish comprehensive measles, mumps, and rubella guidelines consistent with the current recommendations of ACIP. References

1. Williams W, Atkinson W. Measles among health care workers, 1990 [Abstract 1520]. In: Programs and abstracts of the 32nd interscience conference on antimicrobial agents and chemotherapy. Washington, DC: American Society for Microbiology, 1992:364. 2. Centers for Disease Control. Measles prevention: recommendations of the Immunization Practices AdvisoryCommittee (ACIP). MMWR 1989;38(S-9):1-5, 10. 3. Enguidanos R, MascolaL, Frederick P. A survey of hospital infection control policies and employee measles cases during Los Angeles County's measles epidemic, 1987 to 1989. AJIC AMJ INFECTCONTROL1992;20:301-4. 4. Wong RD, Henry D, Mathisen G, GoetzMB. Severe adult (A) measles (M) [Abstract 93]. In: Program and abstracts of the 32nd interscience conference on antimicrobial agents and chemotherapy. Washington, DC: American Society for Microbiology, 1992:126. 5. Centers for Disease Control. Rubella and congenital rubella syndrome-New York City. MMWR 1986;35:770-4, 779. 6. Centers for DiseaseControl. Update on adult immunization: recommendations of the Immunization Practices Advisory Committee (ACIP). MMWR 1991;40(RR-12):5-7, 19-27.