Q: At a diagnostic centre, blood sample was being collected for HIV testing. After 5 hours, the HIV infected blood bottle fell down to the floor and a drop of blood, by mistake, touched a person’s tongue. What will happen to him?

A:Firstly, we don't know whether the blood was actually HIV positive. However, as the blood was for HIV test, it is quite possible that the blood was positive. Even if it was HIV positive and one drop touched the tongue, it is not very likely that the person will get infected. It is possible even though it is unlikely. The person should have been put on PEP. Post exposure prophylaxis is available free of cost to health care workers who get accidental exposure. If PEP was not started within a few hours of exposure, there is no point in starting it late. For reassurance the person concerned should get a HIV test done at the appropriate time. This will stop the person worrying. At the end I must tell you that it is not likely that the infection will occur, chances are very low.