If you have high levels of HIV in the blood, you may also have high levels of HIV in semen or vaginal fluid. People with high viral load are likely to be more infectious.

Anti-HIV treatment that reduces viral load in the blood usually also reduces HIV levels in semen and in vaginal fluid. However, even if the viral load in your blood becomes undetectable after treatment, this doesn't mean that HIV has disappeared from your semen or vaginal fluid. You still risk passing on the virus during sexual intercourse if you aren't using a condom with your partner. Untreated sexually transmitted infections, most notably gonorrhoea, can increase viral load in sexual fluids and mean that the risk of passing on HIV to your partner is greater if you are not using a condom.

Anti-HIV treatment has been proven effective in reducing mother-to-baby HIV transmission. If you are pregnant or planning to conceive, discuss your treatment options with your doctor. If you have undetectable viral load whilst pregnant, the risk of passing HIV to your baby will be very low.