ABSTRACT
Hepatitis B virus (HBV) and hepatitis C virus (HCV) are major causes of transfusion-transmitted infection (TTI). In Thailand, the prevalence of HBV infection in new blood donors has decreased gradually from 7.1% in 1988 to 2.6% in 2009. This drastic decline in HBV prevalence is mostly the result of an effective expanded program on immunization (EPI) against HBV; the current coverage rate with HBV vaccine in newborns is more than 98% nation-wide. The prevalence of HCV infection, has decreased at a slower rate due to lack of HCV vaccination. The use of healthy volunteer blood donors and nucleic acid amplification technology (NAT) has also contributed to the steady decrease in rates of HBV and HCV infections. We summarize the current status of the EPI program for preventing HBV and the current strategy of HBV and HCV screening in new blood donors.
Subject(s)
Blood Donors , Hepatitis B/epidemiology , Hepatitis B/prevention & control , Hepatitis C/epidemiology , Adolescent , Adult , Aged , Hepacivirus , Hepatitis B Antigens/blood , Hepatitis B Vaccines , Hepatitis B virus/immunology , Hepatitis C/prevention & control , Humans , Mass Screening , Middle Aged , Thailand/epidemiology , Young AdultABSTRACT
BACKGROUND: An evaluation by the National Blood Center, the Thai Red Cross Society, of two commercial multiplex nucleic acid tests (NATs; the Chiron PROCLEIX ULTRIO test and the Roche Cobas TaqScreen MPX test) for screening Thai blood donors for hepatitis B virus (HBV), hepatitis C virus, and human immunodeficiency virus Type 1 identified 175 HBV NAT-reactive/hepatitis B surface antigen (HBsAg)-negative donors. The classification of the HBV infection of these donors was confirmed by follow-up testing. STUDY DESIGN AND METHODS: Index samples were tested for HBV serologic markers and HBV viral loads were determined. Donors were followed for up to 13 months and samples were tested with both NAT assays and for all HBV serological markers. RESULTS: Of 175 HBV NAT-yield donors, 72 (41%) were followed. Based on the follow-up results, the majority of donors who were followed had an occult HBV infection (66.7%), followed by donors with a primary, acute infection (26.4%). The majority of donors in this latter group (20.8%) were in the window period. Three donors (4.2%), who were anti-HBs positive, had a reinfection or breakthrough infection. CONCLUSION: The majority of donors detected during routine screening, who were HBsAg negative and NAT reactive, had an occult HBV infection, thus validating the decision to introduce NAT for blood donations in Thailand.
Subject(s)
Blood Donors , Diagnostic Errors/prevention & control , Hepatitis B/diagnosis , Mass Screening/methods , Nucleic Acid Amplification Techniques/methods , DNA, Viral/analysis , Follow-Up Studies , Hepatitis B Surface Antigens/analysis , Hepatitis B virus/isolation & purification , Humans , Nucleic Acid Amplification Techniques/standards , Serologic Tests/methods , Thailand/epidemiology , Viral Load/methodsABSTRACT
BACKGROUND: Blood donations collected at the National Blood Center, the Thai Red Cross Society, Bangkok, in 2007 were tested by nucleic acid amplification technology (NAT) using the Chiron TIGRIS/Procleix Ultrio test and the Roche cobas s 201/cobas TaqScreen multiplex (MPX) test. STUDY DESIGN AND METHODS: The sensitivity, specificity, and robustness were determined by testing 486,676 seronegative blood donations. Samples from each day of collection were divided into two sets; the odd-numbered samples were tested individually on the TIGRIS and the even-numbered samples were tested in pools of 6 on the cobas s 201. The status of reactive samples was confirmed by duplicate testing of samples from the plasma bag to calculate the test specificity. Reactive samples were tested on the alternate system and followed up. RESULTS: The analytical sensitivity of both systems met the 95% limits of detection claimed by the respective package inserts. No cross contamination was seen with either system. Test specificity was 99.93 and 99.90% for the Procleix Ultrio and cobas TaqScreen tests, respectively. The NAT yield rates for human immunodeficiency virus Type 1 (HIV-1), hepatitis C virus (HCV), and hepatitis B virus (HBV) were 1:97,000, 1:490,000, and 1:2800, respectively. Several occult HBV donors, the majority of whom were detected by both tests, were also identified. The HIV-1 and HCV window cases were detected with both tests. CONCLUSION: The performances of the systems and tests indicated that both were acceptable for routine NAT by the National Blood Center, the Thai Red Cross Society. However, the Procleix Ultrio test appeared to be less sensitive than the cobas TaqScreen test for HBV.
