Doctor-office infections are rare, says Linda Chirarello, an epidemiologist at the CDC. But in January, the New York digs of Seymour Halpern, MD, became Blue Moon Central when 20 of his patients suddenly got sick with hepatitis B, setting off an HIV panic as well (none tested positive). Halpern agreed to stop giving injections while the state and city health departments launched an investigation -- and the tabloids had a field day. Officials attributed the outbreak to "the improper administration of injectable medication from multi-dose vials." In other words, the virus was likely passed through the doc's reuse of a dirty needle. "My client has entered into an agreement with the department of health," said Halpern's lawyer, James Fabian. "He's 80 years old -- he's retiring from practice."