The prevalence of hepatitis B serologic markers in suburban paramedics

The

Journal

of Emergency

Medane.

Vol. 7. pp. 41-45.

Printed I” the USA

1989

l

Copyright

0 1989 Pergamon

Press

PlC

THE PREVALENCE OF HEPATITIS B SEROLOGIC MARKERS IN SUBURBAN PARAMEDICS Denise J. Fligner, *Emergency

Department, SDepartment Reprint address:

MD,**§

Herbert N. Wigder, MD,*,§ Phillip M. Harter, MD*,§ Mark Jewell, MPH,* Patt Perlman, RN*

Robert M. Fliegelman,

DOt*jl

tsection of Infectious Diseases, *Epidemiology, Christ Hospital and Medical Center, Oak Lawn Illinois, of Family Practice, /(Department of Internal Medicine, Rush Medical College, Chicago, Illinois Herbert N. Wigder, MD, Associate Chairman, Department of Emergency Medicine. Christ Hospital, 4440 W. 95th Street, Oak Lawn, IL 60453

0 Abstract-Urban emergency medical servicespersonnel have documented hepatitis B virus (HBV) seropositivity rates ranging from 0.6% to 25%. We studied 85 suburban paramedics for Hepatitis B serologic markers. All paramedics answered a questionnaire describing age, race, duration of employment, known hepatitis exposure, blood transfusions, gamma globulin injections, and Hepatitis B vaccination. HBV surface antibodies (Anti-HB$ were present in 6/85 (7.1%) paramedics of whom one (1.2%) had reactive HBV core antibodies (Anti-HB,). No paramedic had HBV surface antigen (HB,Ag). Seropositivity was not associated with duratibn of employment, or exposure to a patient with either jaundice (28.2%) or confirmed hepatitis B (20.0%) within the six months prior to testing. The 7.1% prevalence of HBV markers found in this group of suburban paramedics is intermediate between previously reported rates for urban paramedics. We conclude that prehospital personnel do not constitute a homogenous occupational category at risk for hepatitis B infection.

and

lence in the general United States population of less than 5 % . This occupational risk has been correlated largely with exposure to blood contaminated with the virus and needlestick accidents (2). Prevalence rates of HBV serologic markers in various occupational or social groups have been used to determine which groups will benefit from hepatitis B vaccination. More recently, vaccination has been recommended based soley on membership in a social or occupational group thought to be at increased risk of HBV exposure (3). Studies of urban emergency medical technicians (EMTs) and paramedics in Houston (4), Boston (5), and Seattle (6) have documented rates of HBV serologic markers from 13% to 25 %. These initial reports concluded that EMT and paramedic personnel are at substantial risk of occupational Hepatitis B infection and would benefit from vaccination (4,5,6). In contrast, two recent reports from Salt Lake City, Utah (7), and the Minnesota Twin Cities area of Minneapolis and St. Paul (8) found HBV serologic markers in only 0.6% and 1.7% of prehospital personnel. Such inconsistencies in the reported prevalence of HBV markers raise doubts about the classification of prehospital personnel as a homogenous occupational group with substantial risk of hepatitis B exposure. We postulated that the risk of HBV in our suburban emergency medical services (EMS) system might be intermediate between large metropolitan areas and lower risk areas. To our knowledge, no previous study has evaluated the prevalence of serologic markers to

0 Keywords-hepatitis B; hepatitis B vaccine; emergency medical services;prevalence; surburban

INTRODUCTION

Health care workers experience an increased risk of exposure to Hepatitis B virus (1). Select medical groups show a prevalence of HBV serologic markers as high as 30%, as compared to the baseline prevaFunding for this study was provided by the Christ Hospital and Medical Center Medical Education Fund.

Prehospital Care focuses on the issuesand practices that directly affect the type and quality of care administered by the emergency physician in the emergency department; and is coordinated by Peter Pans, MD, Denver General Hospital, Denver Colorado. RECEIVED: 31 December 1987; SECOND SUBMISSION RECEIVED: 4 April 1988 0736-4679/89 $3.00 + .OO ACCEPTED: 28 April 1988

m -

41

42

D. J. Fligner et al

HBV in suburban prehospital personnel. In order to make a recommendation to suburban paramedics in our emergency medical services system concerning the risk of exposure to Hepatitis B and the need for Hepatitis B vaccination, we undertook a prevalence study of Hepatitis B serologic markers in suburban paramedics who live and work within two miles of the City of Chicago.

METHODS Six suburban fire departments from communities within and neighboring the Christ Hospital Emergency Medical Services System were asked to participate in this study. None of the communities are contiguous with the City of Chicago, although the municipalities are located as near as 2 miles to Chicago. Fire department policy dictates that all Emergency Medical Services (EMS) personnel live within their respective municipalities that range in size from 11,000 to 60,000 people. No suburban personnel were excluded because of prior residence or employment in a large city. It is unknown how many of the community citizens actually work or travel to the City of Chicago regularly. All paramedics in each of the fire departments were asked to participate in the study. During their usual duties, paramedics are exposed to medical and trauma patients and are responsible for insertion of intravenous catheters, venipuncture, administering intravenous medications, airway management, and endotracheal intubation. At the time of the study, the use of protective barriers such as gloves was left to the discretion of the individual paramedics and occurred rarely. Paramedics with less than 1 year of work experience (defined as 2ooO hours of assigned shifts with patient care contact) were excluded from the study. Participants were tested for serologic markers to Hepatitis B virus and answered a confidential questionnaire describing age, race, type and years of employment, personal history of hepatitis or jaundice, blood transfusion, pooled gamma globulin or hepatitis immune globulin injections, and household contact with persons with jaundice or hepatitis. Occupational exposure within the previous 6 months to patients with either jaundice or confirmed Hepatitis B was also recorded. We did not obtain information concerning homosexual activity. Blood samples collected by venipuncture were tested for hepatitis B surface antigen (AUSRIA-II R), hepatitis B surface antibody (AUSAB R) and hepatitis B core antibody (CORZYME R) using enzyme and

radioimmunoassay techniques (Abbott Laboratories, North Chicago, Illinois). All data were gathered in the fall of 1985. The study was approved by the Christ Hospital and Medical Center Committee on Human Investigation and assured confidentiality of both questionnaire data and serology results. Statistical analysis was performed on a microcomputer using the statistical programs SAS-PC@ and SYSTAT? Chi-square analysis (two-tailed Fisher’s Exact for small samples) was used for categorical variables and the Student t test for continuous data. RESULTS Ninety-five (95) paramedics were eligible for this study of whom 5 declined to participate. An additional 5 paramedics had received Hepatitis B vaccination and were excluded from analysis. Questionnaires and serology were available from 85 suburban paramedics. There were 6 paramedics (7.1%) who had any HBV serologic marker (Table 1). Only one (1.2%) paramedic was positive for both Anti-HB, and AntiHB,. The 5 other paramedics tested positive for AntiHB, alone (5.9%). No paramedic was positive for HB,Ag. All paramedics in the study sample were white and 96% were male. None of the 3 female paramedics tested seropositive. Only small numbers of paramedics reported a personal history of jaundice (2), hepatitis (3), blood transfusion (4), immunoglobulin therapy (8), or household contact to hepatitis (2). None of these exposures was significantly associated with HBV markers, although the small number of persons reporting these exposures make statistical interpretation difficult (Table 2). Work exposure to patients with documented hepatitis was likewise not significantly associated with seropositivity, although the association with jaundice approached statistical significance (.05). When mean work experience was compared, duration of employment was not significantly different between seropositive and seronegative paramedics (7.7 v 9.8 years). Chi-square analysis similarly showed no association between seropositivity and duration of paramedic experience greater than 5 years compared to work experience from 1 to 5 years. DISCUSSION Our prevalence rate of 7.1% for HVB serologic markers in suburban paramedics is intermediate between previously reported rates for EMS personnel em-

HEW in Suburban Table 1. Prevalence Personnel HBV

43

Paramedics of Hepatitis B Markers in EMS Number Reactive (n = 6/85)

Marker

None 6 (7.1 o/o)

WA Anti-HB, With Anti-HE, Anti-Ha, only

1 (1.2%)

5 (5.90/o)

Table 2. Comparison of EMS Personnel Serological Reactivity Variable Age (years f SD) Duration of Employment (years f SD) Personal history of: hepatitis 6 jaundice blood transfusion gamma globulin Household exposure to hepatatitis B Occupational exposure to hepatatis B to jaundice a(

) indicate

column

by Hepatitis B Virus

Reactive n=6

Nonreactive n=79

P

30.3k7.3

32.5 f 7.9

.52

9.8+5.1

.33

1 (16.7)a 1 (16.7) 0 1 (16.7)

2 1 3 7

(2.5) (1.3) (3.8) (8.9)

.20 .14

1 (16.7)

1

(1.3)

.14

15 (19) 20 (25.3)

.60 .05

7.7_+ 3.5

2 (33.3) 4 (67.7)

1 .oo

.46

percentages.

ployed in large metropolitan areas (12.1%-25%) (4,5,6) and the exceptionally low rates found in Salt Lake City (0.6%) (7) and the Minnesota Twin Cities area (1.7%) (8). This wide range emphasizes the heterogeneity of exposure in a presumably homogenous occupational group. Of the paramedics in our study with positive serology, 84% (5/6) had Anti-HB, as the only marker; this pattern is also typical of low intensity exposure (9,lO). Differences in the prevalence of HBV markers in EMS personnel may be partially due to differences in occupational factors: the frequency of exposure to blood and body fluids, needle stick precautions, the use of gloves, and duration of employment. We found no statistical relationship between duration of employment and seropositivity, using either difference between means or Chi-square analysis. Other studies of prehospital personnel have reported conflicting results concerning the influence of work duration on seropositivity. Valenzuela et al (6) also found no relationship between seropositivity and mean length of service (6.2 v 7.0 years). In contrast, Kunches et al (5) found a trend towards an association between mean duration of employment and seropositivity which did not reach statistical significance (p=.ll; 8.9 v 7.2 years) and Pepe et al (4) showed a strong correlation between prevalence of HBV mark-

ers and years of work exposure using Chi-square analysis. Nevertheless, differences in duration of employment do not account for the wide range in prevalence of HBV markers between EMS systems: average duration of employment in low prevalence studies (12 years in Salt Lake City (7) and 6.6 years in the Minnesota Twin Cities (8) area) is comparable to high prevalence studies. It is probable that regional differences in the service population prevalence of HBV account for some of the variation in prehospital prevalence rates. Occupational exposure risk to HBV has been shown to be significantly lower in rural hospitals (11,12) and increased in communities with populations in excess 1 million persons (13). Regional differences in the service population prevalence of HBV might similarly affect the prevalence of HBV markers in prehospital personnel. To explore this idea, we compared our study results (suburban Chicago) and the reported results for other prehospital personnel to the corresponding population rates for Hepatitis B (Table 3). Population rates were obtained from published studies or from the appropriate city or county board of health for the years 1983, 1984, and 1985, as available. Simple inspection of the corresponding rates from the different locations suggests that the prevalence of HBV serological markers in paramedics is influenced by the incidence of hepatitis B in the population. While no statistical relationship can be drawn from this table, the data suggest that significant differences exist between service populations. The CDC currently classifies health care workers as being at either low or intermediate risk of hepatitis B infection, based on the prevalence of HBV markers and the frequency of blood contact. Prevalence rates of HBV serologic markers between 10% and 30% are typical of health care workers with frequent exposure to blood and characterize social or occupational groups at intermediate risk of contracting hepatitis B. Health care workers with no or minimal exposure to blood generally have prevalence rates in the range of 3% to 10% and are considered to be at low risk of hepatitis B infection. The CDC recommends prophylactic vaccination for intermediate risk groups; prehospital workers (EMT-Ps) are included in the intermediate risk group based on frequent exposure to blood and intitial reports of prevalence rates ranging from 13% to 25%. However, our results and those of others have shown lower than expected HBV prevalence rates in this occupational group. Prevalence rates of HBV markers that fall below the intermediate risk range have important implica-

D. J. Fligner et al Table 3. Hepatitis 6 Prevalence in EMS Personnel Population Incidence of Hepatitis B EMT Prevalence

Location

Y

Population Rate

Year

Chicago Fligner

Suburban et al ‘85a

7.1%

2.01100,OOO

‘83-85

Chicago

Proper

-

6.6/100,000 3.5/100,000

‘84 ‘85

Minnesota Twin Cities Hankins et al ‘86a

1.7%

3.5/100,000

‘83(15)

Salt Lake City Kunches et al ‘85b

0.6%

8.01100,000 15.0/100,000

‘84 ‘85

Houston Pepe et al ‘85b

12.1%

10.1/100,000

‘83-85

Seattle Valenzuela

25.0%

27.2/l 00,000 64.9/100,000 89.1/100,000

‘83 ‘84 ‘85

15.3/l

‘85

et al ‘83a .

Boston Kunches

18.0%

00,000

needlestick) to documented (HB,Ag positive) exposure could provide a rational basis for vaccination policy by individual EMS systems. Potential exposure of paramedics via needlestick is common, especially in the first year of employment (17). However, postexposure prophylaxis and vaccination following documented exposure to HB,Ag positive blood may still be a cost effective alternative for systems with a low risk of HB,Ag exposure despite a high frequency of potential exposures (18). Currently, the cost of vaccine far exceeds the cost of testing. Substantial decreases in the cost of vaccine are necessary for prophylactic vaccination to become the least costly alternative for EMS systems with a low risk of hepatitis B exposure and infection. SUMMARY

et al ‘82a

aYear data was collected. bYear report was submitted.

(Date of data collection

not reported.)

tions for vaccination programs based entirely on membership in an occupational risk group (14). Osterholm and Garayalde found that studies that looked only at HBV prevalence significantly overestimate the incidence (annual attack rate) of HBV infection (15). Mulley et al, in a cost effectiveness study on indications for HBV vaccination, found that for health care workers with a HBV prevalence rate of 10% and high exposure to HBV (annual rate of OS%), vaccination is not cost effective until the annual attack rate exceeds 5% (16). Cost-effectiveness analysis is particularly relevant for EMS systems likely to have low HBV prevalence and attack rates: rural systems, suburban systems, and systems serving populations less than a million persons. Seroepidemiologic studies combined with attack rates and the ratio of potential exposure (eg,

The current recommendations for hepatitis B vaccination from the CDC classify EMTs as health care workers with frequent blood contact and substantial risk of acquiring HBV. Our findings and those from Salt Lake City and the Minnesota Twin Cities area indicate that EMS personnel do not constitute a homogenous occupational risk group. It is likely that regional, geographic, and occupational factors interact to varying degrees to determine overall risk for hepatitis B virus and that classification soley by occupational category does not accurately determine risk. Further cost effectiveness studies based on a broader spectrum of epidemiologic data are necessary to clarify the indications for vaccination in prehospital personnel. Acknowledgement- We would like to thank Oak Lawn Fire Department, Bridgeview Fire Department, Orland Park Fire Protection District, Palos Heights Fire Department, North Palos Fire Protection District, and Chicago Ridge Fire Department for their participation in this study.

REFERENCES 1. West DJ. The risk of hepatitis B infection among health care professionals in the United States: a review. Am J Med Sci. 1984;287:26-33. 2. Hadler SC, Doto IL, Maynard JE, et al. Occupational risk of hepatitis B infection in hospital workers. Infection Control. 1985;6:24-31. 3. CDC: Recommendations for protection against viral hepatitis. MMWR 1985;34(22) in JAMA. 1985;254:197-217. 4. Pepe PE, Hollinger FB, Troisi CL, Heiberg D. Viral hepatitis risk in urban emergency medical services personnel. Ann Emerg Med. 1986;15:454-7. 5. Kunches LM, Craven DE, Werner BG, et al. Hepatitis B exposure in emergency medical personnel; prevalence of serologic

markers and need for immunization.

Am J Med. 1983;75:269-

72.

Valenzuela TD, Hood EW, Copass MK, et al. Occupational exposure to hepatitis B in paramedics. Arch Intern Med. 1985; 45:1976-g. 7. Clawson JJ, Jacobson JA. Prevalence of antibody to hepatitis B surface antigen in emergency medical personnel in Salt Lake City, Utah. Ann Emerg Med. 1986;15:183-4. 8. Hankins DG, Karess DE, Siebold CM, et al. Hepatitis B vaccine and hepatitis B markers: cost effectiveness of screening prehospital personnel. Amer J Emerg Med. 1987;5:2056.

6. 9.

Dienstag JL, Ryan DM. Occupational exposure to Hepatitis B

HBV in Suburban

Paramedics

virus in hospital personnel: infection or immunization? Am J Epidemiol. 1982;115:26-39. 10. Kessler HA, Harris AA, Payne JA, et al. Antibodies to hepatitis B surface antigen as the sole marker in hospital personnel. Ann Intern Med. 1985;103:21-6. 11. Harris JR, Finger RF, Kobayashi JM, et al. The low risk of hepatitis B in rural hospitals; results of a seroepidemiologic survey. JAMA. 1984;252:3270-2. 12. Dandoy S, Kirkman-Liff B. Hepatitis B prevention in small rural hospitals. West J Med. 1984;141:627-30. 13. Denes AE, Smith JL, Maynard JE, et al. Hepatitis B infection in physicians; results of a nationwide seroepidemiologic survey. JAMA. 1978;239:210-2. 14. Lohiya G, Lohiya S, Caires S, et al. Occupational exposure to

45 hepatitis B virus: analysis of indications for hepatitis B vaccine. J Occup Med. 1984;26:189-96. 15. Osterholm MT, Garayalde SM. Clinical viral hepatitis B among Minnesota hospital personnel; results of a ten-year statewide survey. JAMA. 1985;254:3207-12. 16. Mulley AC, Silverstein MD, Dienstag JL. Indications for use of hepatitis B vaccine, based on cost-effectiveness analysis. N Engl J Med. 1982;307:644-52. 17. Hockreiter MC, Barton LL. Epidemiology of needlestick injury in emergency medical service personnel. J Emerg Med. 1988;6:9-12. 18. Bock KB, Tong MJ, Bernstein S. The risk of accidental exposure to hepatitis B virus via blood contamination in medical students. J Infect Dis. 1981;144:604.