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Indian Journal of Community Medicine

Prevalence of Hepatitis-B Surface Antigen (HBs-Ag)Among Health Care Workers

Author(s): K.K. Asok Kumar*, P.K. Baghel*, C.B. Shukla**, M.K. Jain*

Vol. 25, No. 2 (2000-04 - 2000-06)

*Deptt. of Medicine, **Deptt. of Microbiology S.S. Medical College & Associated G.M. Hospital, Rewa (M.P.) - 486001

Abstract:

Research question: What is the prevalence of Hepatitis-B surface antigen among health care workers?

Objective: To study the seroprevalence of Hepatitis-B among health care workers.

Study design: Cross sectional.

Participants: Health care workers of a medium sized teaching hospital, Rea (M.P.)

Study variables: Age, sex, occupational category, duration of hospital service, vaccination status against hepatitis-B.

Statistical analysis: Proportions, Chi-square test.

Results and conclusion: Out of the 408 health care workers tested for HBsAg, 9 were positive (2.21%) . Postivity was significantly more among males. There was positive association with history of needle pricks and blood donation. The marked difference in HBs Ag positivity between vaccinated and non-vaccinated groups points to the need of early and complete vaccination of all health care workers.

Keywords : HBsAg prevalence, Health care workers.

Introduction:

Hepatitis-B infection is considered to be an occupational risk for health care workers. The factors attributed to this high prevalence are exposure to blood and blood products of infected patients. The enhanced risk of hepatitis-B infection has been reflected by clusters of hapatitis-B cases, high hepatitis attack rates, discreet outbreaks of hepatitis-B as well as high prevalence of HBsAg and anti-HBs1.

There are also reports of health care workers transmitting hepatitis-B infection to patients though this is exceedingly rare 2-4.

Since test for HBsAg and anti-HBs have become available; several studies of prevalence of these markers have been published in which hepatitis-B surface antigenemia approximated 1% and that of anti-HBs fell in 15-20% range5-8.

At most institutions no attempts are made to minimize direct ungloved contact with blood of HBsAg positive patients. Moreover, most HBsAg positive materials handled are not labelled as such. This is especially true in the case of rural hospitals in India where even the basic facilities are not available and lack of awareness appalling.

Nowadays, effective vaccines are available against hepatitis-B. But even among the high risk groups like health care workers, a major proportion are not vaccinated. It is in this context that this study was conducted so that an immunization policy can be evolved for health care workers.

Material and Methods:

There are several markers for the serological diagnosis of hepatitis-B. In this study, HBsAg prevalence was studied using reverse passive haemaglutination (RPHA) technique among health care workers of S.S. Medical College and associated Gandhi Memorial Hospital, Rewa (M.P.) over a period of one year from October 1998 to September 1999.

The study group contained 408 health care workers of various occupational categories. Information was collected from them by asking to fill up the questionnaire given to them at the time of collecting blood samples. Information included detailed occupational history apart from general data like age, sex, socio-economic class etc. Exposure to blood and/or blood products and the way in which it occurred, use of personal protection (using disposable gloves syringes), history of blood donation or transfusion, vaccination status and sexual practices were asked in the questionnaire. Blood samples were collected in previously sterlized vials and serum separated by centrifugation. RPHA test for detecting HBsAg was done using commercially available RPHA kits (Austragen latex code no. 25946).

Results:

Out of the 408 health care workers who participated in the study, 9 turned out to be HBsAg positive 2.21%) HBsAg positivity in relation to age group and sex is shown in the following Table.

Table I: Age and sex specific HBsAg positivity.

Age groups (years) No. of subjects HBsAg positive
11-20 51 1 (1.96%)
21-30 172 5 (2.91%)
31-40 93 2 (2.15%)
41-50 70 1 (1.43%)
>50 22 -  
Sex
Male 193 7 (3.62%)
Female 215 2 (0.93%)

Majority of participants were of 21-40 years age. Most of the positive cases also belonged to this age group (7 out of 9). The difference in positivity between males (3.62%) and females (0.93%) was statistically significant.

Table II: HBsAg positivity in relation to occupation.

Occupation No. of subjects HBsAg positive
Doctors 113 3 (2.65%)
Nurses 142 2 (1.41%)
Lab technicians 25 0  
Hospital assistants 80 3 (3.75%)
Sweepers 30 1 (3.33%)
Office attendants 18 0  

No statistically significant difference in positivity was found though hospital assistants showed a relatively higher positivity. Among doctors no significant difference in positivity was observed between surgical (3.33%) and non-surgical (1.88%) doctors. Out of the 78 student nurses tested 2 were HBsAg positive while no staff sister was positive among the 64 tested.

Among the 320 participants who did not have a past history of blood donation 2 were HBsAg positive, while four out of the 88 who donated blood were HBsAg positive (difference statistically significant p<0.005). Significantly higher prevalence of HBsAg was observed among those with frequent and occasional needle pricks (8/291-2.75%) as compared to those with rare or no history of needle pricks (1.157-0.6%).

Table III: HBsAg positivity in relation to vaccination status.

Vaccination status No. of subjects HBsAg positive
Fully vaccinated 158 1 (0.63%)
Incomplete course of vaccination 15 0  
Not vaccination 235 8 (3.40%)
Total 408 9 (2.21%)

The difference in positivity among vaccinated and non-vaccinated groups was highly significant (p<0.001).

Discussion:

Out of 408 participants tested, 9 were positive for HBsAg (2.21%). This was significantly more than the prevalence of HBsAg in general population in different parts of India. The prevalence was 0.1% in the general population of Delhi as per the study of Sama et al (1971)9. Studies conducted in Western countries also have shown 2-10 times higher prevalence of serologic markers for hepatitis-B in health care workers5-10.

The prevalence of 2.21% in this study is less than that observed in some of the previous Indian studies (Elavia et al, 1992-10%)11. This difference may be due to the fact that more and more of health care workers are vaccinated now as vaccine against hepatitis-B has become freely available. 173 out of 408 participants of the present study had received partial or full course of vaccination against hepatitis-B.

8 out of 9 positive cases were below 40 years of age. This higher positivity in younger participants may be because of less number of cases studied in the older age groups. Another explanation is that there is more chance of acquiring infection as they are inexperienced in their job and so the contact with blood and blood products, needle pricks etc. was more. Also most of them were unimmunized when entering health care services.

Seropositivity was significantly more in males (7/193-3.62%) than females (2/215-0.93%). In earlier studies Hovig et al (1985)12 and Elavia et al (1992)11 also have made similar observations.

Statistically significant difference in positivity was not observed among different occupational categories. Highest positivity (3.75%) was found among hospital assistants (ward ayas/ boys), while no positive case was found among lab technicians and office attendants. Lack of awareness seems to be the reason for this increased prevalence among hospital assistants.

In contrast with some of earlier studies1,10 which showed a significantly higher positivity among doctors of surgical specialities as compared to others, this study did not find any significant difference among these groups. This may be due to the fact that most of the doctors in the present study were vaccinated against hepatitis-B. (99/113-87.6%).

Among nurses only two positive cases were found and both of them were student nurses. This is probably because they are doing bulk of the ward work and so exposure is more. Another important factor may be, while most of staff nurses were vaccinated (85.93%) only a few student nurses (6.4%) were vaccinated against hepatitis-B.

5 out of the 320 cases (1.56%) who never donated blood were HBsAg positive as compared to 4/88(4.55%) who had donated blood (p<001). This increased prevalence may be due to the incorrect hospital techniques used during procedures of blood grouping such as using same needle for finger pick and not using disposable sterile equipments for taking blood.

There was a significantly higher incidence of HBsAg among those with history of frequent and occasional needle pricks as compared to those with rare or no needle pricks. This is in accordance with earlier studies6.

Among those who had taken complete course of vaccination against hepatitis-B, one was positive for HBsAg (0.63%) and among non-vaccinated 8 persons (3.40%) were positive. One case that was positive among vaccinated group might have acquired HBsAg before vaccination and he turned out to be a chronic carrier when the follow-up was done after 24 weeks.

The study concludes that health care workers are at increased risk of acquiring hepatitis-B infection as compared to general population and it is an occupational hazard to them. The significant difference in HBsAg positivity among vaccinated and non-vaccinated groups calls for complete immunization of all health care workers.

In United States there has been a dramatic decrease in the prevalence of HBsAg among health care workers and they are now at lower risk of hepatitis-B infection than general population13. This interesting observation is food for thought for those making immunization policies in India.

References:

  1. Dienstag JL, Ryan DM: Occupational exposure to hepatitis-B virus in hospital personnel: Infection or immunization. American Journal of Epidemiology 1982; 115: 26-39.
  2. Levin ML, Maddrey WC, Wands JR et al: Hepatitis transmission by dentists. JAMA 1974; 228: 1139-40.
  3. Grob PJ, Bischof B, Naeff F: Cluster of hepatitis-B transmitted by a physician. The Lancet 1981; 1218-20.
  4. Hapaz R, Seidlein LV, Averhoff FM et al: Transmission of hepatitis-B virus to multiple patients from a surgeon without evidence of inadequate infection control. The New Eng1 J Med 1996; 334: 549-54.
  5. Lewis TL, Alter HL, Chalmers TC et al: A comparison of the frequency of hepatitis-B antigen and antibody in hospital and non-hospital personnel. New Eng1 J Med 1973; 289: 647-51.
  6. Pattison CP, Maynard JE, Berquist KR et al: Epidemiology of hepatitis-B in hospital personnel. American Journal of Epidemiology 1975; 101: 59-64.
  7. Denes AE, Smith JL, Maynard JF et al: Hepatitis-B infection in physicians: Results of a nationwide survey. JAMA 1978; 239: 210-12.
  8. Maynard JE: viral hepatitis as an occupational hazard in the health care profession. In: Vyas GN, Cohen SN, Schmid R, eds. Viral hepatitis. Philadephia: Franklin Institute Press, 1978: 321-31.
  9. Sama SK, Anand S, Malaviya N et al: Australia antigen in normal population and patients of viral hepatitis in Delhi. Indian J Med Res 1971; 59: 64-08.
  10. Palmer DL, Barash M, King R et al: Hepatitis among hospital employees. The Western Journal of Medicine 1983; 138: 519-23.
  11. Elavia AJ, banker DD: Hepatitis-B virus infection in hospital personnel. Natl Med J India 1992; 5: 265-68.
  12. Hovig B, Rollag H, Dahl O: Antibody to hepatitis-B surface antigen among employees in the National Hospital, Oslo, Norway: A prevalence study. Am J. Epidemiol 1985, 122: 127-34.
  13. Mahoney FJ, Steward K, Hu H et a;: Progress towards the elimination of hepatitis-B virus transmission among health care workers in United States. Arch. Intern Med. 1997; 157: 2601-5.
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