Researchers at the International AIDS Vaccine Conference 2008 debated as to whether macaques monkeys should be the “gatekeepers,” the preliminary test subjects for what could be human clinical trials of new vaccines, South Africa's The Times reports.

Dr. Paul Johnson from the Primate Research Center at Harvard Medical School favors using macaque monkeys because “[Simian Immunodeficiency Virus] SIV/macaque models accurately mirror the course of HIV infection in humans.”

However, Dr. David Weiner of the School of Medicine at the University of Pennsylvania argues that macaque monkeys are biologically different and thus an “imperfect model” for humans. “Microbicides protected macaques, and they did not protect the humans,” Dr. Weiner said.

Neither side of the debate argued that monkey data should block Phase I trials (the first phase of testing a drug for safety and efficacy) of new vaccine research.