Nowhere in the world is transfused blood considered 100% safe. This, despite the fact that each unit of blood is mandatorily tested for infection, among other things, before transfusion. This happens because several infections, such as Hepatitis A, B, C and Human Immunodeficiency Virus, have a window period during which the virus doesn’t show up in a blood test. So, if a person contracts the HIV today and decides to donate blood the next day, the laboratory that tests the blood will not detect the virus in it. The window period for HIV is usually between three weeks and three months, depending on the technology used at the laboratory. Even the best-available technology in the market right now – the Nucleic Acid Amplification Test – only reduces the window period to seven days. It does not entirely eliminate the risk. But India fares poorly Despite this limitation, many countries have not reported a case of HIV transmission through blood transfusion for years now. Canada...