Question
What is the risk from one exposure and would 3TC help protect me afterwards?
7 August 2007. Related: All topics, HIV testing, HIV transmission.
I had unsafe sex with my friend … Next morning I came to know it was not her first time. I got an HIV test done for both of us next morning and got the results on the same day. The test showed she was HIV positive.
What are the chances of me getting infected?
I started taking medicine Lamivir (3TC) – 150mg after 20 hrs of sex… Is there any thing that can be done to prevent it?
Answer
HIV antibody tests, (including ‘rapid’ tests) are not able to detect HIV until after the body has generated an immune response to the infection. With HIV this usually needs a minimum of 4 weeks after exposure, and often extends to 3 months or longer.
Most testing centres recommend that results are only accurate for your HIV status three months prior to the test.
The chance of infection from any single exposure is generally very low, but is related to viral load, whether the HIV positive partner is on treatment and if there are other sexually transmitted infections.
Using HIV treatment after exposure may reduce the risk of infection, but this usually involves taking combination therapy (three drugs) for four weeks, starting as soon as possible after exposure and not after 72 hours.
The Lamivir (3TC) may have an effect on its own, but if your already were HIV positive, this would risk you developing resistance. If you have undiagnosed hepatitis B, this is also not recommended because that Lamivir (3TC) is also active against hepatitis B.