HIV viral load rebounds rapidly in semen ARVs are stopped study says

Researchers studying HIV therapeutic vaccines have found that when patients were taken off their HIV antiretrovirals (ARV) that the levels of virus in their semen rebounded rapidly.

The men taken off their ARVs were taking part in HIV cure and therapeutic vaccine trials, part of which is temporarily coming off their treatment for close monitoring – this period is known as an analytical treatment interruption (ATI).

French researchers highlighted a case from 2019 where a man participating in such as study transmitted HIV to his female partner during an ATI.

An analysis was carried out, following 10 male participants in the VRI02 trial who also opted into a semen sub-study between April and December 2015.

The participants of VRI02 were randomised to receive either two experimental therapeutic vaccines or a placebo. All participants had been on ARVs for a minimum of 18 months before joining VRI02 and were put through an ATI from week 36 through 48. The 10 sub-study participants provided semen samples alongside the standard blood samples.

When ATI was started all 10 participants had a blood plasma viral load below 20 copies per ml, two weeks into the ATI trial (week 38) 8 out 10 participants saw their blood plasma viral load rebound with the other two rebounding in weeks 42 and 44. The median blood plasma viral load during ATI rebound was 132,000 copies per ml.

At the start of ATI (week 36) the viral load in the participants’ semen was less than 60 in 9 out of 10 cases. But by week 40, four weeks into ATI, seminal viral load had rebounded to infectious levels in 8 out of 10 participants.

The study’s authors concluded: “Our data demonstrate rapid and high HIV rebound in semen after ATI, raising concerns about high risk of HIV sexual transmission during HIV cure trials.”

Whilst the quantity of data here is small it highlights the need for clearer communication around risk and risk reduction for those taking part in trials that require an ATI period, or those pausing their HIV therapy for other reasons.