A new study finds that having a superinfection—in other words, contracting a second strain of HIV—does not apparently accelerate HIV disease. To come to this conclusion, researchers studied 144 HIV-positive women in Mombasa, Kenya, between 1993 and 2008, during which 21 of them became superinfected.

The women who contracted a second strain of HIV saw their viral loads rise more quickly than those who still only had one viral strain. The superinfected women also apparently lost CD4 cells more quickly, although this difference was only of borderline statistical significance, meaning there was not much statistical heft behind the notion that it did not happen by chance.

Regardless of these two findings, the superinfected women’s HIV disease did not accelerate, meaning that it took them about the same amount of time as those with one strain of the virus to be diagnosed with certain conditions indicating HIV’s progress in harming the body.

Keshet Ronen, PhD, a researcher at Fred Hutchinson Cancer Research Center in Seattle and the study’s lead author, notes that the superinfections all took place before the women were treated for HIV, as did the recorded changes in their viral load and CD4 levels.

“Now that treatment is so widespread I think it’s important to remember that superinfection can change people’s clinical course if they become infected with a drug-resistant variant,” Ronen says. “And so that is a caution. But in terms of the biological effects of acquiring a second virus in itself, the effect seems to be quite modest.”