Potential Occult Hepatitis B Infection among First Time Blood Donors in Thingangyun Sanpya General Hospital

Dr. Su Myat Htike, M.B.,B.S., M.Med.Sc. (Microbiology)
Dr. Hnin Zi, M.B.,B.S., M.Med.Sc. (Microbiology), Ph.D (Medical Microbiology)
Dr. Yi Yi Kyaw, M.B.,B.S., M.Med.Sc. (Microbiology)
Professor Win Win Maw, M.B.,B.S., Ph.D (Shimane), FACTM (Australia), Dip. Med. Ed.

ABSTRACT

Transfusion transmitted hepatitis B has always been a dreaded disease, with the incidence of increased transmission through donated blood. The screening test for hepatitis B infection is detection of HBsAg that does not rule out the risk of transmission of hepatitis B as the donor may be in the “window period”. During this period, detection of antibody to hepatitis B core antigen (anti-HBc) serves as a useful serological marker. The aim of this study was to detect the occurrence of occult hepatitis B infection among first time blood donors in Thingangyun Sanpya General Hospital.

This study was a laboratory-based cross- sectional descriptive study conducted at blood bank of Thingangyun Sanpya General Hospital during January to November 2014. In this study,frequency of HBsAg among first time blood donors using was 4% (n=6) in 150 samples. Anti- HBs prevelance using anti-HBs ELISA kit was found in 40.7% (n=61). Of these, 2% (n=3) of anti-HBc using immunochromatographic test kit was detected from samples in 144 HBsAg negative first time blood donors as occult hepatitis B infection.

INTRODUCTION

Hepatitis B virus (HBV) infection is a serious public health concern. Currently, two thirds of HBV infection carriers live in the Asia Pacific region and are at risk of developing terminal hepatic diseases, such as cirrhosis and hepatocellular carcinoma².

It is well known that blood transfusion is associated with a large number of complications, some are only trivial and others are potentially life-threatening, demanding for meticulous pre- transfusion testing and screening. The use of unscreened blood transfusion keeps the patient at risk of acquiring many transfusion-transmitted infections (TTI) like hepatitis viruses (HBV, HCV), human immuno-deficiency viruses (HIV), syphilis, malaria etc.

Despite continuous technical improvement in blood donation screening, hepatitis B infection remains a major risk of transfusion transmitted viral infection. The residual risk of hepatitis B is related to the pre-seroconversion window period (only HBc antibody as the only serological marker) and with or without anti-HBs as occult hepatitis B virus infection. Decades of clinical observation showed that HBsAg-negative / anti- HBc-positive blood could transmit HBV. Sometimes, occult hepatitis B infection may have no serological marker of hepatitis B infection except low viral DNA.

HBV DNA detection rate is highest in subjects who are anti-HBc positive but anti-HBs negative (HBsAg negative, anti-HBs negative, anti-HBc positive)⁵. Occult HBV infection (Hepatitis B DNA positive) has been reported in 0.1%-2.4% of HBsAg-negative,anti-HBc- positive (± anti-HBs) blood donors in low endemic Western countries such as the United States⁴. The rate of occult HBV infection might be increased in highly endemic developing countries.

Nowadays, antibody tests for hepatitis B core antigen (anti-HBc) are used in Western countries, to further reduce the risk of infectious agents in the blood supply¹¹.

AIM

With subjects who were first time blood donors in Thingangyun Sanpya General Hospital, the aim of this study was : (1) to determine the proportion of hepatitis B surface antigen (HBsAg) positivity (2) hepatitis B surface antibody (anti-HBs) positivity (3) to find out the hepatitis B core antibody (anti-HBc) among hepatitis B surface antigen (HBsAg) negative cases (to study the occurrence of occult hepatitis B infection)

MATERIALS AND METHODS

A laboratory-based cross sectional descriptive study was done in Thingangyun Sanpya General Hospital and Blood Bank (Thingangyun Sanpya General Hospital) and Experimental Medicine Research Division, Department of Medical Research (Lower Myanmar) from January 2014 to November 2014.

A total of 150 first time blood donors were included in the present study.

Collection of blood samples

After receiving written informed consent, proforma was filled out for each subject. Under sterile and aseptic condition, 2 ml of blood was taken from each donor.

Procedure

Blood samples were collected and centrifuged at Thingangyun Sanpya General Hospital. Serum samples were sent to Department of Medical Resrarch (Lower Myanmar) and stored at (-20° C). All serum samples were tested for HBsAg and anti-HBs using SD HBsAg and anti- HBs ELISA kit. Then HBsAg negative serum were further tested for anti-HBc using anti-HBc immunochromatographic test kit.

RESULTS

Most of the blood donors (46%; n=69) were between 21 to 30 years of age, followed by age group 18-20 years (36.7%; n=55), 31–40 years (12.7%; n=19), 41–50 years (3.3%; n=5) and 51– 54 years (1.4%; n=2). In the study population, (55.33%; n=83) of blood donors were male and (44.67%;n=67) were female. According to blood group distribution, most of first time blood donors were of blood group “O” (34.7%; n=52), blood group “A” 28% (n=42), blood group “B” (22.7%; n=34) and blood group “AB” (14.7%;n=22), respectively.

The seroprevalence of HBsAg among first time blood donors was (4%;n=6) of the total 150 first time blood donors. These HBsAg positive blood donors were male (Table-1).

Among 150 first time blood donors, anti-HBs was positive in (40.7% ;n=61) of blood donors. In male blood donors, anti-HBs was positive in 42% (n=35) and negative in 58% (n=48). Among female blood donors, anti-HBs was positive in 39% (n=26) and negative in 61% (n=41) (Table- 2).

Hepatitis B core antibody (Ig M+ IgG) total was found in 2% (n=3) of 144 HBsAg negative first time blood donors. These three anti-HBc positive blood donors also had anti-HBs. Other 40% (n=58) of HBsAg negative donors were anti- HBs positive and 58% (n=83) were anti- HBs negative (Figure -2).

Immunization status was categorized into three groups. The majority of blood donors with no immunization history of hepatitis B vaccine was 56.7% (n=85), those with immunization history present was 13.3% (n=20) and unknown immunization history was 30% (n=45) .

Figure 3.History of hepatitis B vaccine imunization among anti-HBs positive blood donors

According to immunization history, among 83 male blood donors, 12% (n=10) were immunized, 59% (n=49) were not and immunization history unknown in 29% (n=24) . Among 67 female blood donors, 15% (n=10) were immunized, 54% (n=36) were not and immunization history unknown in 31% (n=21). In this study, anti-HBs was present in 90% (n=18) of 20 blood donors who received HBV vaccine and was also detected in 16.5% (n=14) of 85 blood donors who did not receive immunization and 64.4% (n=29) of 45 immunization history unknown blood donors.

DISCUSSION

In the present study, 150 serum samples of first time blood donors between 18 to 60 years age group from Thingangyun Sanpya General Hospital were taken for detection of occult hepatitis B infection. Most of the blood donors were voluntary blood donors and some were replacement blood donors.

Age, gender, blood group and vaccination status

In this study, the most common age group of blood donors was between the age of 21 to 30 years (46%). Age group between 18-20 years was the second most common (36.7%). This is consistent with that of WHO report in which the most prevalent age group of donors in Myanmar were between 25 to 44 years (46.10%), followed by age group 18 to 24 years (29.7%). In the Republic of Korea, blood donars age group between 18 to 24 years was most common (43.75% ), followed by aged group 25 to 44 years (27.29%)¹⁷.

In this study, male blood donors comprised 55.33% of the study population and female blood donors were 44.67%. Male blood donors are more fit for blood donation, because of the lower risk of anaemia, low blood pressure and low body weight. Potential women donors in the reproductive age were not accepted due to presence of anaemia or low body weight. According to the findings, women health needs to be improved with a better nutritional diet and iron supplementation.

Knowledge of blood group distribution is important for clinical studies. This information can help reduce the mortality rate and provide safe and sufficient blood supply to reduce preventable deaths.

In this study, blood group “O” was the most frequent blood donors (34.7%), followed by blood group “A” ( 28%), blood group “B” (22.7%) and the least frequent blood group was “AB” (14.7%). Similarly, in the United States of America, the most frequent blood group O was 46% and blood group A was 41%. However, in one Indian study, blood group “B” was the most frequent (35.48%) and blood group “AB” was the least common (34.33%) ¹².

Regarding immunization history for hepatitis B vaccine, a considerable number of blood donors could not answer their immunization status. Positive immunization history of hepatitis B vaccine was 13.3%, negative immunization history of hepatitis B vaccine was 56.7% and the rest 30% were immunization history unknown.

HBsAg carrier rate in blood donors

Out of 150 blood donors tested, only 4% (n=6) was positive for HBsAg. Reducing trends of HBsAg carrier rate among general population and blood donors was evident by the studies of Tin- Nwe-Oo in 1993, Than-Than-Su in 2004, and Yi- Yi-Kyaw et al., in 2007. Among the general population, seroprevalence was found to be 11.1%, 6.17%, and 5.7%, respectively ^16,15,19. Hepatitis B surface antigen testing done from 2002 to 2006 in the National Blood Bank of Yangon, Myanmar showed that HBsAg positivity was 2.9%, 4.3%, 5.1%, 4.23% and 3.74% respectively14. These results are not much different from results obtained from this study. However, compared to present data from Brazil and Egypt, HBsAg detection rate was found to be higher in this study ^2,11.

In the present study, all HBsAg positive donors were male blood donors with five samples from monks and one from a general worker from Maupin Township. Among the monks blood donors, four of them were from the same monastery. It can be implied that transmission occured via close contact and the sharing of sharp instruments.

Similarly, it was found that the prevalence rate of HBsAg among monks was higher than that of the general population ⁷. This might be due to the increased chance of frequent and prolonged close personal contact with infected persons. Therefore, this particular population group is assumed to have increased risk of getting infection, have higher need for effective hepatitis B immunization and need a better confimation of sufficient response to protective levels of anti-HBs antibody.

Hepatitis B surface antibody

In the present study, Hepatitis B surface antibody was positive in 61(40.7%) of 150 blood donors; 42% (n=35) of 83 male donors, and 39% (n=26) of 67 female blood donors.

A study for detection of anti-HBs status of general population in Myanmar done by using qualitative anti-HBs ELISA test kit in 2007 was shown to be 38.2% ¹⁸. Screening of anti-HBs among blood donors in Tamil Nadu from 2010 to 2011 study, hepatitis B surface antibody prevalence was 3% ⁹.

In the present study, 20 out of 150 blood donors had history of immunization with hepatitis B vaccine. Among them, only 18 blood donors had anti-HBs and no anti-HBs in the rest of two blood donors. Of these two persons, one had taken only hepatitis B vaccine for 2 times. The other had taken full dose of hepatitis B vaccine. So these data showed that assessment of anti-HBs after HBV vaccine immunization is essential to determine the level of immune response.

Out of 85 blood donors who were absent in immunization status, 14 (16.47%) were positive for anti-HBs. In addition, hepatitis B surface antibody was detected in 64.4% (n=29) of who were blood donors with unknown immunization status. This may be due to previous infection with complete recovery or they had also taken hepatitis B vaccine immunization.

The result of the study revealed health education about hepatitis B vaccine among general population is still needed and immunization program is also needed to improve.

Anti-HBc total (IgM/IgG)

In the present study, 3 (2%) samples in 144 HBsAg negative first time blood donors were positive for anti-HBc total.

Occult hepatitis B infection of blood donors in Indonesia showed that anti- HBc was positive in 43.4% of HBsAg negative blood donors and HBV DNA (Occult hepatitis B infection ) was detected in 8.1%, nearly equalling the average 9.4% HBsAg prevalence in Indonesia ¹³.

In the present study, all these three anti-HBc positive blood donors also had anti-HBs. So, they may acquire infection in the past and recover and gain immunity.

In this study, there was no total anti-HBc positivity in both HBsAg and anti-HBs negative blood donors showed our donor population had no window period infection.

Hepatitis B DNA was detected 12.2% among anti-HBc positive, HBsAg negative blood donors of Iran population 3. According to serological status tested in Saudi Arabia blood donors for occult hepatitis B infection, anti-HBc positive/ anti-HBs positive blood donors were 6.3% of sample population and anti-HBc positive/ anti- HBs negative blood donors were 1.2% respectively ¹.

Of these anti-HBs positive/ anti-HBc positive blooddonors’population, HBVDNAwasdetected in 3.2%. This result shows HBV DNA was present in serum of anti-HBs positive/ anti-HBc positive blood donors. It is an important public health problem that anti-HBc positive/ anti-HBs positive serum is not a sign of total eradication and the need for a better screening system to prevent post transfusion HBV infection ¹.

Zobeiri (2013) proposed that anti-HBc should be used as a less ideal surrogate marker for identifying potential seropositive OBI individuals in cases of blood, tissue, or organ donation if highly sensitive HBV DNA testing is not feasible¹⁹.

This study showed that 2% of study population were anti-HBc total positive and further analysis for presence of HBV DNA is needed.

CONCLUSION

In this study, anti-HBs was present in 90% (n=18) of 20 blood donors who received HBV vaccine and it could also detect in 16.5% (n=14) of 85 blood donors who did not receive immunization and 64.4% (n=29) of 45 immunization history unknown blood donors.

Anti-HBs positivity is not a sign of total HBV eradication. Some HBsAg negative individuals with positive anti-HBc and/ or positive for anti- HBs may be positive for HBV DNA. Nucleic acid testing (NAT) like polymerase chain reaction (PCR) should be done to detect HBV DNA to confirm occult hepatitis B infection. Therefore, there is a need for setting up a strategy to prevent post transfusion occult hepatitis B infection and raise an important public health issue that the absence of HBsAg alone does not exclude the possibility of viral transmission.

Therefore, anti-HBc and HBV DNA should be tested routinely in blood donors and if there were positive of anti-HBs titer, the blood should be discarded to ensure a completely safe blood transfusion.

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Author Information

1. Medical Officer, National Health Laboratory, Yangon
2. Lecturer,Department of Microbiology, University of Medicine 2, Yangon
3. Deputy Director, Experimental Medicine Research Division, Department of Medical Research (Lower Myanmar)
4. Professor and Head, Department of Microbiology, University of Medicine 2, Yangon