Q and A


My viral load is undetectable, will it rebound?

Hi, so I am a 29 year old heterosexual male and have been taking Stribild and later Genvoya for more than 5 years now. I have good adherence and have remained undetectable.

I understand that risk is of transmission to a partner even without condoms would be negligible as long as that remains the case. However my check-ups where I get my viral load counts are only every three months so I have these questions:

– If resistance was unexpectedly to develop, how fast could my viral load increase in the three-months span in between checkups? Could it realistically increase fast enough for me to be a risk to someone?

– In the rare event that I do miss a single dose, how much would viral load increase from that and, if nothing else happens, how fast would it decrease again to undetectable levels?

I really appreciate your efforts and with them hope to better be able to reassure future partners.


Thanks for getting in touch.

Lots of studies show that with good adherence, viral load very rarely rebounds. Taking the meds every day keeps viral load undetectable. Because it doesn’t rebound, drug resistance will not develop.

This is why viral load and CD4 tests in the UK are now only checked every 6-12 months. Once your CD4 is above 500 it might not even be checked every year.  This means viral load rebound whwith good adherence is a theoretical, rather than real concern.

Until someone knows this, it is common to still worry that viral load might rebound, even after years of effective treatment, but this does not happen. The key here is adherence, as long as you take you meds, you will stay undetectable.

Missing a single dose of your meds will not affect this – or even missing a couple of doses (though this is not recommended).

In terms of risks to your partner, it would probably take missing meds for  1-2 weeks for viral load to become detectable again. However, missing more than a couple of days is the time when resistance can develop, at low levels.

If you are unlucky and resistance does develop from missing doses, then treatment might not work when you start taking the meds again. Instead, drug resistance might instead develop and become stronger. This is when the time between viral load tests would become important. If resistance is developing, than over a couple of months viral load could become very high – tens of thousands of copies/mL. This would risk transmission – and also, by then, this would be drug resistant HIV.

Apart from missing meds, the rare cases that viral load can rebound are if you start another medicine that interacts with your HIV meds. This is why your doctor or pharmacist needs to know about other things you take.

This includes over-the-counter drugs (like antacids for stomach problems), supplements and recreational drugs.


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