Thursday, October 02, 2003

Monday, I heard Sten Vermund speak about the history of HIV epidemiology at the 2003 International Meeting of the Institute of Human Virology. Dr. Vermund mentioned, parenthetically, that bleach does not effectively remove virions from injection drug equipment, and thus is not recommended as a prevention technique.

I hadn't heard that. Given that I do HIV prevention work with my patients, 80% of whom have injection drug use histories, I thought it was a bit odd that I hadn't heard that - so I went researching. After several minutes of digging, I found a set of 1997 CDC recommendations for IV drug users emphasizing the importance of new, sterile syringes, with bleach mentioned as a backup option. The CDC's HIV FAQ also pushes the use of new syringes and mentions bleach as a less satisfactory alternative. Neither CDC site provided details of how needles should be cleaned with bleach, although established guidelines do exist.

An older CDC fact sheet presents a 1991 finding that addicts who reported always cleaning needles with bleach had the same seroconversion rates as addicts who didn't report using bleach. (I have to wonder about the accuracy of addicts' reports on their injecting behavior, though, given the typical state of mind immediately pre-injection.) Other studies have found that addicts often think they've rinsed their needle for a full 30 seconds when they haven't. These seem to be the results which led to the de-emphasis of bleach. But another recent study suggests that the recommendation might've been changed too soon:
"What we found is that for the type of syringe usually used by drug injectors, even a one-tenth diluted solution of bleach successfully disinfects the syringe if the solution is drawn in and squirted back out," Heimer says. "Even when we stacked the deck and left 10 times more blood in the syringe than is usually found, full strength bleach was effective in 152 of 153 attempts. We even found that rinsing three times with clean water reduced the likelihood of recovering live virus by 99%."

Most of the patients I see in my research don't share needles - Baltimore has an effective needle exchange program - and none of my therapy clients currently inject drugs. But damn it, it shouldn't take an hour of research for me to find out the latest evidence-based prevention recommendations. I should be drowning in the latest recommendations. But for some reason, that doesn't happen - especially when the latest recommendations contradict previous recommendations.

The best example of this is the spermicide nonoxynol-9. It used to be recommended because it was found to kill HIV in vitro, but in real life it actually increases the risk of HIV infection in both women and in gay men. Many AIDS service organizations still distribute condoms treated with n-9 - even the Institute of Human Virology, one of the premier HIV research institutions in the world. Information dissemination on this topic has just been poor. You shouldn't be able to get within ten feet of a condom without being exposed to full information about n-9. They should have warning labels on displays in stores. At a minimum, everyone working in the field should have had it hammered into their heads by now. I don't know why that hasn't happened.