|Year : 2019 | Volume
| Issue : 2 | Page : 74-78
Evaluation of hepatitis B vaccination status and immune response among clinicians in a tertiary care hospital in South India
R Jayaprada, N Ramakrishna, B Vasavi, B Venkataramana, KK Sharma
Department of Microbiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
|Date of Web Publication||11-Nov-2019|
Assistant Professor, Department of Microbiology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Background: Hepatitis B virus (HBV) infection remains an important health issue with an estimated 2 billion people worldwide infected with HBV. The risk of contracting HBV by health-care workers (HCWs) is four times greater than that of the general adult population. Protection is defined as immunoglobulin G anti-hepatitis B virus surface antigen antibodies (IgG anti-HBsAbs) level ≥10 mIU/mL following a successful vaccination course.
Methods: Three hundred and seventeen clinicians participated in the present study. Vaccination history for hepatitis B was obtained. The concentration of IgG anti-HBsAbs in the serum was determined by quantitative enzyme-linked immunosorbent assay.
Results: Two hundred and twenty nine participants (72.2%) had already received a complete course of HBV vaccination, 78 participants (24.6%) had received incomplete course and 10 participants (3%) were non-vaccinated. Among the clinicians having a complete history of vaccination, 86% had protective immunity; while of the 71.7% participants who had incomplete vaccination had protective immunity. We found that four clinicians (1.2%) could not attain protective anti-HBsAb level ≥10 mIU/ml, were designated as non-responders after second vaccine series.
Conclusions: Even with full vaccination some of the clinicians have not achieved protective IgG anti-HBsAb titres. Hence, it is imperative that protective antibody titre ≥10 mIU/mL must be maintained in all HCWs. Non-responders must be identified and should be counselled regarding how to prevent hepatitis B infection.
Keywords: Hepatitis B antibodies, hepatitis B vaccination, non-responders
|How to cite this article:|
Jayaprada R, Ramakrishna N, Vasavi B, Venkataramana B, Sharma K K. Evaluation of hepatitis B vaccination status and immune response among clinicians in a tertiary care hospital in South India. J Clin Sci Res 2019;8:74-8
|How to cite this URL:|
Jayaprada R, Ramakrishna N, Vasavi B, Venkataramana B, Sharma K K. Evaluation of hepatitis B vaccination status and immune response among clinicians in a tertiary care hospital in South India. J Clin Sci Res [serial online] 2019 [cited 2019 Dec 16];8:74-8. Available from: http://www.jcsr.co.in/text.asp?2019/8/2/74/270750
| Introduction|| |
Hepatitis B virus (HBV) infection remains an important health issue, throughout the world. It is estimated that more than 2 billion people worldwide have been infected with HBV. Of these, nearly 360 million individuals are chronic carriers and at risk of serious illness and death due to cirrhosis of the liver or hepatocellular carcinoma. In a mathematical model, it was estimated that 620,000 persons died worldwide for the year 2000 from HBV-related causes. In the surviving birth cohort for the year 2000, it was estimated that 64.8 million will be infected from HBV with a range of 1–4 million deaths, in the absence of vaccination. In India, hepatitis B surface antigen prevalence among general population ranges from 2% to 8% which places India in an intermediate endemicity zone, and India with 50 million cases is the second largest global pool of chronic HBV infection. The risk of contracting HBV by health-care workers (HCWs) is four times greater than that of the general adult population. The avoidance of occupational blood exposure is the primary preventive means for the transmission of HBV. Immunisation and after exposure management are integral components of a complete infection control programme for this group.
Protection defined as anti-hepatitis B virus surface antigen antibodies (anti-HBsAb level ≥10 mIU/mL) following first, second and third doses of the recombinant vaccine has been reported to be 20%–30%, 75%–80% and 90%–95%, respectively., Studies have demonstrated that vaccine induced protection persists at least 11 years and booster vaccination for immunocompetent children and adults is not recommended for long-term protection., Immunocompromised patients and high-risk groups such as HCWs, however, should be monitored and receive a booster vaccination if their anti-HBsAb level decrease below 10 mIU/mL. There are only few studies are available from India regarding the vaccination status among HCWs, particularly clinicians and laboratory personnel. This study was undertaken to find out IgG anti-HBsAb status among clinicians in a tertiary care hospital to identify those who are at risk so that booster/full course of HBV vaccination may be administered to these individuals. It was a part of routine hospital infection control programme.
HCWs with a reduced immune response to HBV vaccine in a high disease prevalent population are at great risk. Therefore, it is crucial to check post-vaccination anti-HBsAb levels in all HCWs.
This strategy will ensure safety at work by reducing nosocomial transmission and will have a cost-effective impact at an individual as well as at the national level, which is very much desired in a resource-limited country.
| Material And Methods|| |
The study was done at Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India, which is a tertiary care centre. Three hundred and seventeen clinicians participated in the study and were enrolled with their consent. Clinicians those who were willing to participate in the study were taken as study participants. Criteria for selection were based on the hepatitis B surface antigen (HBsAg) status, and clinicians who were positive for hepatitis B surface antigen were excluded from the study. The study was carried out from 2013 to 2017. Data regarding age, gender and full course of hepatitis B vaccine were obtained from each participant. Vaccination history was obtained from individual immunisation records. All the participants have signed the consent form, and Institutional Ethics Committee clearance was obtained before starting the study.
Three mL of peripheral venous blood was collected from the clinicians and were sent to the department of microbiology. The concentration of immunoglobulin G antibodies to hepatitis B surface antigen (IgG anti-HBsAb) in the serum was determined by quantitative enzyme-linked immunosorbent assay (ELISA) (DSI, Italy). The test was performed as per manufacturer's instructions.
The categorical variables were analysed using Chi-square test. The correlations between the variables were determined by multiple regression analysis. P < 0.05 was considered statistically significant. The data were analysed using Statistical Package for Social Sciences (SPSS)(version 16.0, 2007).
| Results|| |
The assessment of IgG anti-HBsAb titre in vaccinated clinicians indicated a statistically significant association between antibody titration and complete vaccination series. The age range of the study subjects was 21–65 years. In our study, 196 (61.8%) were males. At the time of sampling, 229 individuals (72.2%) had received a complete course of HBV vaccination earlier, 78 (24.6%) had received incomplete course and 10 (3%) were non-vaccinated [Table 1]. Of 317 clinicians, 169 (53.3%) had an antibody titre >100 mIU/mL, 85 (26.8%) had an antibody titre between 10 and 100 mIU/mL and 63 (19.8%) had an anti-HBsAb titre <10 mIU/mL [Table 2]. Of 196 males, 106 (54%) had an antibody titre >100 mIU/mL, 51 (26%) had an antibody titre between 10 and 100 mIU/mL and 39 (19.8%) had an anti-HBsAb titre <10 mIU/mL and out of 121 females, 63 (52%) had an antibody titre >100 mIU/ml, 34 (28%) had an antibody titre between 10 and 100 mIU/mL and 24 (19.8%) had an anti-HBsAb titre <10 mIU/ml [Table 3].
|Table 1: Status of hepatitis B virus vaccination of participants (n=317)|
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|Table 2: Distribution of anti-hepatitis B surface antigen antibodies titre among clinicians (n=317)|
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|Table 3: Gender-wise distribution of anti-hepatitis B surface antigen antibodies titre among clinicians (n=317|
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The difference between anti-HBsAb titre in the vaccinated (both fully and incompletely vaccinated) (82.4%) and those not vaccinated (10%) was significant. Variables of vaccination and completion of its course were positively associated with anti-HBs titre (P< 0.05).
Of 229 fully vaccinated clinicians, 142 (62%) had an antibody titre >100 mIU/mL, 55 (24%) had an antibody titre between 10 and 100 mIU/mL and 32 (14%) had an anti-HBsAb titre <10 mIU/mL. Of 78 incompletely vaccinated clinicians, 27 (34.6%) had an antibody titre >100 mIU/mL, 29 (37%) had an antibody titre between 10 and 100 mIU/mL and 22 (28.2%) had an anti-HBsAb titre <10 mIU/mL. In non-vaccinated clinicians, only one (10%) had an antibody titre between 10 and 100 mIU/mL and 9 (90%) had an anti-HBsAb titre <10 mIU/mL [Table 4].
|Table 4: Anti-hepatitis B surface antigen antibodies status of participants according to vaccination status|
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Of 53 clinicians who had an anti-HBsAb titre <10 mIU/mL were subjected to second vaccine series, and we found that four clinicians (1.2%) could not attain protective anti-HBsAb level >1 mIU/ml, were designated as non-responders [Figure 1].
|Figure 1: Percentage of non-responders among clinicians with anti-hepatitis B surface antibody titre <10 mIU/mL after second vaccination series|
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All 317 participants tested negative for HBsAg by ELISA.
| Discussion|| |
Universal hepatitis B vaccination is known to bring enormous benefits to communities where HBV infection is endemic. Hepatitis B vaccination has been associated with the elimination or reduction of childhood hepatocellular carcinoma and more recently, virus-associated membranous nephropathy. Guidance on hepatitis B was issued in 1993 requiring all staff primarily performing exposure prone procedures to be immunised against hepatitis B and to check their serological response.
The objective of the study was to assess adequate immunity level for hepatitis B using anti-HBsAb titre among HCWs (clinicians) and vaccination of non-immune or partially immune subjects using full/booster dose of hepatitis B vaccine. The antibody response to HBsAg is an important serological marker for vaccine-induced immunity to HBV.
In our study, only 72.2% had received three doses of hepatitis B vaccine, while 24.6% had incomplete vaccination and 3% were not vaccinated at all. These observations indicate that hepatitis B coverage is still inadequate in our country even among high-risk groups such as HCWs. The main reason behind this could be due to failure in the implementation of vaccination policies established by the hospital management. In a study done at New Delhi, 96% of doctors were vaccinated. All the participants were tested for HBsAg by ELISA and all were found to be negative.
Two hundred and fifty-three (82.4%) of our study participants with complete and incomplete vaccination had protective (>10 mIU/mL) anti-HBsAb levels as against 1 (10%) of those who were not vaccinated had protective anti-HBsAb levels. These results show that 14% of the clinicians with complete vaccination and 28.2% of the clinicians with incomplete vaccination had not achieved protective antibody levels and were still susceptible to acquire infection. These individuals were advised to take full course of hepatitis B immunisation.
However, 10% (one clinician) of those clinicians who were not vaccinated at all attained protective antibody levels probably due to the acquisition of natural infection sometime in the past which conferred natural immunity to these individuals.
Another important observation that our study highlights is 26.8% of our clinicians were partially immune including in both fully vaccinated and incompletely vaccinated and were still at risk of hepatitis B infection. These clinicians were advised to take a booster dose of hepatitis B vaccine.
Our findings are similar to a study conducted on microbiology laboratory workers in Maulana Azad medical college, New Delhi, India, in which those who had received a complete course of HBV vaccination, 73.5% showed protective levels of antibodies. The anti-HBsAb levels in participants who were non-vaccinated or where their vaccination status is incomplete were 39.1% and 53.3%, respectively.
Clinicians with anti-HBsAb levels <10 mIU/mL were recalled and revaccinated again with full vaccination series (0, 1, 6 months) and advised to return after 1 month of the full vaccination series for a repeat test.
After the second vaccine series, we found that four clinicians (1.2%) could not attain protective anti-HBsAb level >10 mIU/mL and were designated as non-responders. In a study it was observed that non-response rate to hepatitis B vaccine was approximately 6%. Age over 50 years, chronic disease states such as kidney disease, liver disease, diabetes mellitus, those on immunosuppressive drugs and those with a genetic predisposition may be considered as predictors for non-response to hepatitis B vaccination. Rest 49 clinicians were completely protected. Hepatitis B vaccine 'non-responders' who test negative for hepatitis B infection are at risk for being infected and should be counselled regarding how to prevent a hepatitis B infection and to seek immediate medical care to receive a dose of hepatitis B immunoglobulin if they have been exposed to potentially infected blood.
From this study, we concluded that even with full vaccination some of the clinicians have not achieved protective anti-HBsAb titres for which we have to implement testing of anti-HBsAb for all clinicians as a mandate irrespective of their vaccination status. This we can achieve among HCWs by health education. Those who do not achieve the protective anti-HBsAb titres should be given booster doses or full vaccination based on antibody titre levels. All HCWs should be then monitored for their immune status regularly, and booster doses should be administered to those who have become susceptible to hepatitis B infection. It is essential that long-term follow-up studies should continue to monitor groups of immunised individuals to determine if clinically significant breakthrough episodes of hepatitis B occur or whether the carrier state develops. The outcome will help in future decisions on booster policies.
We would like to thank all the participants who volunteered for the study and the staff of Microbiology department.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]