When are people with HIV most likely to sexually transmit the virus?
There is currently some disagreement regarding the impact of untreated primary (also called acute) HIV infection versus untreated chronic HIV infection on infectiousness and sexual transmission, and their relative contributions to onward transmission. Although studies have found that viral load during untreated primary HIV infection is much higher – and therefore individuals are more infectious – than during untreated chronic infection, it is also understood that since untreated primary HIV infection only lasts a matter of weeks or months, the opportunity for transmission is lower compared with untreated chronic HIV infection, which can last for years or even decades. In fact, a recent US study utilised mathematical modelling to estimate that fewer than 9% of all new sexually transmitted HIV infections originated in people with untreated primary HIV infection, compared with 48% of new infections resulting from sexual contact with people with untreated chronic HIV infection. However, an
