The latest studies send mixed messages on the pros and cons of drug breaks (strategic treatment interruptions, or STIs). Here’s our four-point guide to sorting them out:

CD4 counts count. The higher your CD4s before you went on meds, the better you’ll do off them, say two recent Italian studies. They found that HIVers with pre-HAART CD4 counts between 200 and 500 coasted safely for well over a year med-free. Where does that leave us pill-weary folks who started lower? Read on.

Proceed with caution. In studies, HIVers whose lowest pre-HAART CD4 count had been below 200 quickly dropped back down there when they went off meds. But HIV pro Judith Feinberg, MD, says “sometimes breaks are what my patients need,” so she monitors their CD4s closely and warns as they near the red zone.

No rest for the weary. HIVers fed up with a failing “salvage” regimen may yearn for a break, but research into whether STIs can actually boost their immune systems looks like “a dead duck,” says Florida’s Gerald Pierone, MD. Indeed, most docs agree it’s safer to stay on meds. Still, a San Francisco study suggests that “partial” breaks (stopping the protease inhibitors and staying on the NRTIs) may steady salvagers while saving for later what protease punch is left.

The seven-day itch. HIVers switching between one week on/one week off meds have shown mixed results in suppressing viral load. Pierone says the strategy might work best with a combo of Viread, Emtriva and Sustiva (all last long in your body)—but more study is needed. He adds that five days on/two days off “makes more sense.” We add: Talk to your doc before you slam on any breaks.