Question
Why is viral load sometimes detectable at low levels on ART?
26 March 2026. Related: Adherence, All topics, CD4 and viral load, Resistance.
Hi there, I started Biktarvy in Turkey in March 2025 and I have perfect adherence and take my medication at the exact same time every day. I have recurrent low-level viral load blips though with the following rough results.
March 2025 (Baseline): VL 130,000 c/mL , CD4 400 (13%)
April 2025: VL 109 copies/mL
June 2025: VL undetectable (less than 20 c/mL), CD4 520 (22%)
September 2025: VL 122 c/mL , CD4 790 (24%)
November 26, 2025: VL less than 20 copies/mL , CD4 530 (27%)
February 27, 2026: VL 62 copies/mL , CD4 630 (30%)
Should i worry? is this normal? should i retest? and most importantly is U=U applicable for my case?
Answer
Thanks for your email and for including these detailed responses.
You have had a really good response to treatment and great that your CD4 count, CD4% and viral load are all doing so well. Nothing to worry about over the CD4 and CD4% which are all good and stable.
Viral load blips can be frustrating though and are sometimes difficult to explain. They can also just be related to good or bad luck when you test though. So, for example, if you have only tested a couple of times – in June and November – you would feel differently now and probably wouldn’t have sent this email.
So in some ways, having the extra few tests showing the blips must be frustrating, even though the blips are really low.
This shows that U=U is also still good. None of these viral load results have increased any risk to your partner and U=U still applies. The main cut-off for U=U is to have a viral load lower than 200.
Great that you are also being so careful with adherence and taking meds. This makes it likely that there is nothing wrong with your combination and that over time you will reach undetectable again and stay there.
These are some of the other reasons why viral load can be detectable:
i-base.info/guides/changing/reasons
If for any reason you have slightly lower drug levels, even with good adherence, one easy option that might help would be to take Biktarvy with food.
Although this isn’t often talked about, taking meds with food increases drug levels of 2 of the 3 meds in Biktarvy. Bictegravir exposure increases by about 25% and tenofovir alafenamide by about 50%. This may or may not make any difference but it is easy to do if you want to try it, especially for the 4 weeks before your next viral load test. This would help if Biktarvy just needs a little help, which it rarely does.
Another explanation – number 12 in the article linked above – is that the low level viral load results are not related to Biktarvy not being strong enough. It could be just detecting HIV that is coming from a reservoir of sleeping immune cells. Everyone has this reservoir and the virus being picked up isn’t infectious or complete and isn’t something that is doing you any harm.
This is an aspect of low level viral load that isn’t often discussed but that has definitely been reported – for example here.
i-base.info/htb/44755
If your viral load results are ever a little higher, especially if you get a viral load result above 200 c/mL would be to ask for a drug resistance test. It is unlikely to show you have any drug resistance, but might show rare changes in APOBEC – and your doctor would have to ask specially about this. APOBEC mutations would support that low level viral load is just related to the reservoir, rather than your current combination.
In summary, you are doing really well and U=U is still okay. Taking meds with food might help and you could test this idea by taking with food for the month before your next test.
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