We know that when people living with HIV are on fully effective treatment and have a very low level of HIV in their blood (an undetectable viral load), they can’t pass on HIV during sex. As the campaign slogan says, ‘Undetectable equals Untransmittable’ or ‘U=U’.
But some people ask, once someone has brought the amount of HIV in their blood down to the very low level that is called ‘undetectable’, for how long does it stay that way?
A study of over 8000 people living with HIV in Italy shows that once they are undetectable, they remain that way for 97% of the time.
Professor Giorano Madeddu of the University of Sassari looked at people’s data for an average of five years each. Analysed day by day, a remarkable 96.9% of days were spent with a viral load below 200 (the threshold used in the scientific studies that showed there were no transmissions when viral load was below this level). Only 3.1% of days were spent without viral suppression.
The study was done between 2010 and 2019, with results getting better in more recent years, probably due to improvements in HIV medications.
The study shows what is possible in a country with good access to HIV treatment. Some groups of people had slightly more days with a higher viral load, including unemployed people, people who inject drugs, people born overseas and women. This is probably due to more difficult social circumstances and challenges sticking with healthcare. But none of these groups had more than 6% of days without viral suppression.
“U=U is an essential but straightforward campaign founded on scientific evidence,” says Professor Madeddu. “This data reassuringly suggests that U=U is an appropriate message to communicate to help decrease stigma and increase motivation to remain virally suppressed.”
Click here to read more about this study.
Click here to read more about Undetectable = Untransmittable (U=U).