For positive people, an effective microbicide gel, applied vaginally or rectally to prevent HIV transmission, could one day reduce reliance on condoms. While two earlier microbicides proved ineffective, recent results from a three-year trial of Carraguard—a seaweed-based gel—offer both hope and disappointment:

  • Carraguard was labeled “ineffective [in] blocking HIV transmission”: Among women who used the gel, there were 134 new infections, compared to 151 for those using the placebo.
  • Only 10 percent of participants used Carraguard during sex every single time, though, so the results may stem from poor adherence. Researchers plan to redesign trials to account for personal behavior.
  • Carraguard was proved to be safe on women’s genital surfaces—unlike some other microbicides, which damaged vaginal tissue, making it easier for HIV to penetrate. So Carraguard may provide a base for more potent HIV-preventing compounds in the future.