Researchers are stopping a study early after finding that a shot of experimental drug cabotegravir every two months was 89 percent more effective at preventing HIV infection in women than Truvada pills, although both reduce that risk. Al Jazeera reports that the study involved more than 3,200 participants in seven African countries who were randomly assigned to get either the shots every two months or daily Truvada pills but independent monitors advised stopping the study after seeing that only 0.21 percent of women receiving the shots caught the AIDS virus versus 1.79 percent of women on the pills. “The urgent work now” is to make all prevention medicines affordable and more widely available, said Mitchell Warren, who heads AVAC, formerly known as the AIDS Vaccine Advocacy Coalition, a non-profit focused on prevention efforts that had no role in the study.