New guidelines now urge adults who have been infected with HIV to start taking HIV-fighting drugs as soon as possible, ideally within two weeks of being diagnosed with the infection, rather than waiting to see what happens with white blood cell counts. By preventing the virus from multiplying in the body, this strategy can maintain health and slow—or even stop—the progression to AIDS. Equally important, taking anti-HIV drugs early can decrease the odds that a person will spread HIV to someone else as much as 96%. The new guidelines, from the International Antiviral Society—USA Panel, were presented at the 19th International AIDS Conference, now going on in Washington DC. The new guidelines aren’t without their challenges. Patients must be “ready and willing” to stick with drug therapy, which can be complicated. Another hurdle is cost. An effective anti-HIV drug strategy costs more than $1,000 a month.