Transfusion Transmitted Viral Hepatitis: A Bitter Truth
Viral hepatitis is a widespread infectious disease and a major public health concern, all across the globe. There are five types of hepatitis virus – A, B, C, D, and E but with the same target – the liver. In India, hepatitis B and hepatitis C infections pose a major social and economic burden on the affected person, their family, and the health system. It has been estimated that almost 40 million people are chronically infected with hepatitis B and 6–12 million people are chronically infected with hepatitis C in India.
Recently, on July 28, 2018, the National Viral Hepatitis Control Program was launched under the National Health Mission. In addition to other issues, this program will also address provision of safe blood and blood products through 100 percent voluntary blood donations. According to a report by NACO, only 18 states of India reported more than 80 percent voluntary donation. With a deficit supply of 20–30 lakh blood units and intermediate to high prevalence of hepatitis, safe blood through only voluntary donors is far from possible. Replacement blood donation is still a practice in India and most of the replacement donors pose a higher risk of harboring and transmitting an infection. Therefore, we need other preventive strategies to curb hepatitis infections through blood transfusion.
Transfusion transmitted hepatitis (HBV TTI), through asymptomatic donors is a dreadful possibility as well as a terrible reality. In spite of hepatitis being considered about 10-fold more infectious than HIV, there are many reports and data on HIV-TTI, but sadly, for hepatitis, there is no such data available. In India, it is mandatory that all blood units are screened for HIV, HBV, HCV, syphilis, and malaria. The availability of a number of assays with variable clinical sensitivity makes it very difficult for a blood banker to choose. Usually, these decisions are based on cost and infrastructure rather than sensitivity and clinical utility. The most common technique used mandatorily across most blood banks, is serology-based ELISA/chemiluminescence assay, which relies upon the presence of antibodies in the blood sample. However, the residual risk of infection still remains during the serologically negative window period and during occult infections.
Many reports of TTIs confirm that the current serology-based methods, often fail to detect low viral load infections, window period infections, and occult infections. One highly sensitive technique that has brought down the risk of transmission of such infections is Individual Donor Nucleic Acid Testing (ID-NAT), which reduces the window period and also detects the presence of occult infections and viral mutants. Unlike serology-based techniques, ID-NAT directly targets the viral genetic material (RNA/DNA). ID-NAT tests each sample individually, thus making it highly sensitive and of great clinical utility. Another format of NAT testing is mini-pool NAT, wherein six or more samples are pooled together and tested as one. Sensitivity of this format is debatable across the world, because pooling compromises the ability of detection in case of low viral load infections.
Many countries, especially those in Asia with high prevalence of hepatitis, have adopted ID-NAT as a mandatory screening technique, in addition to serology. In India, more than 100 blood banks, including many premium centers like AIIMS, PGI Chandigarh, CMC Vellore, Medanta – The Medicity, Hinduja, Sir Ganga Ram, KDAH, and Narayana Health have adopted this technology. However, this is just about 5–6 percent of the total blood supply in India. The privilege of safe blood should not be limited to just a few blood banks but should be available for every citizen. Like the state of Karnataka, every state government should go ahead and extend ID-NAT to government blood banks and medical colleges.
