Scientists at Yale are exploring a new method to help cocaine users stay clean and sober. A vaccine that produces antibodies that dull the cocaine high has been found safe in a phase I clinical trial, according to a report in the January 15 issue of the journal Vaccine. The vaccine, TA-CD, is recommended for people who are already trying to kick the habit. “We found that the vaccine is safe and that there is no significant toxicity,” said principal investigator Thomas R. Kosten, M.D., HS ’81, professor of psychiatry, who is testing the vaccine for Xenova Group plc. of Cambridge, England, which owns and is developing the compound. Subjects who received the highest dosages also produced the most euphoria-depressing antibodies.