Q: About two months back I had unprotected vaginal and anal sex with an HIV+ man over 30 times. His viral load is almost undetectable. Though I have had symptoms of primary HIV infection after several different exposures with him (these exposures were months apart), I have tested negative on all tests. My last encounter with him was 10 days back. Could I still be positive and just not be showing it yet? If I turn up to be negative for sure, how could that be, after being exposed so many times? And does an almost undetectable viral load mean I cannot be infected?

A:You did not mention when the first exposure was. It is important to know the approximate date of risk exposure as with the normal tests ( ELISA or rapid tests or even simple tests) a positive test takes some time to appear as it depends on a sufficient amount of antibodies being present in circulating blood and this level of antibody response takes time to develop. This time (window period) may be anything up to 3 months or even longer. If you are testing negative with the usual tests, it does not mean that you are not infected but only that sufficient antibodies are not yet present. It is also quite possible that you did not get the exposure yet, inspite of being exposed. Not every unprotected sexual exposure to an infected person results in infection, in fact the chance of sero-conversion may be as low as 1 in 100 and you may just have been lucky. A person on anti-retrovirals with a very low viral count is still infectious but the degree of infectivity may be reduced. I have not understood why you put yourself at risk when you know your partner is HIV positive. Why not use a condom at the least.