Boston health officials over the weekend began notifying 57 people who, they say, may have been exposed to blood-borne illnesses in the summer of 2011 when they were treated by a city ambulance paramedic now believed to have tampered with vials of painkillers and sedatives.
The telephone calls to potential victims will be followed up Monday with letters offering free medical tests to determine if they were exposed to infectious diseases.
The paramedic, who officials declined to identify, is believed to have tampered with the powerful drugs during a six-week period in the summer of 2011, but officials said they could not be more specific about the exact dates because of an ongoing criminal investigation. No charges have been filed against the paramedic.
Barbara Ferrer, executive director of the Boston Public Health Commission, which runs the city’s ambulance service, said in an interview that officials do not believe the paramedic carried any infectious diseases, but acknowledged that health officials do not know for sure. Nor do they know how the individual may have tampered with the medications, which are in liquid form and are injected.
Health officials are notifying people treated by the paramedic out of an “abundance of caution,’’ she said.
Ferrer said Boston EMS security rules governing controlled substances on its ambulances require that two paramedics be present when patients are given those medications. She declined to say how the suspected paramedic was able to thwart security.
She said 64 patients may have been exposed; seven died shortly after they were transported to the hospital by Boston Emergency Medical Services. Officials believe their deaths were not related to the suspected medication tampering and instead due to their “initial catastrophic injury or medical event.’’
Ferrer said the paramedic has been relieved of all duties since the alleged misconduct was discovered on Sept. 6, 2011.
Officials are not saying why they believe the paramedic tampered with the medicines, but the incidence of health care workers stealing drugs to use for themselves or sell is not uncommon.
News of the Boston incident follows disclosures over the summer that thousands of people may have been exposed to hepatitis C, including some patients at Exeter Hospital in New Hampshire. Authorities say David Kwiatkowski, a medical technician, stole syringes filled with the narcotic fentanyl, injected himself, then returned the contaminated syringes, which were used on patients.
Kwiatowski, arrested in July, has been infected with hepatitis C since at least 2010; tests conducted in recent months have identified at least 30 patients thought to have been infected by him, authorities said.
Thousands more who were treated at the New Hampshire hospital and medical centers in other states where he worked are being screened for hepatitis.
Dr. Ethan Bryson, an associate professor of anesthesia and psychiatry at Mount Sinai School of Medicine, has studied the issue of painkiller thefts by health care workers and said there is a dearth of definitive data to know how widespread the problem may be, but said researchers believe the risk for a health professional to develop an addiction mirrors that of the general population — about 12 to 15 percent.
He said fentanyl — the narcotic stolen at Exeter and one of the drugs the paramedic is suspected of tampering with — is one of the most commonly stolen drugs by health care professionals.
“Fentanyl lends itself to abuse by people who have access to it because someone can take it, get high real quick, and still function after a short while’’ because the effects wear off quickly, said Bryson, whose new book, “Addicted Healers,’’ explores drug addiction by health professionals.
Boston health officials believe the paramedic may have also tampered with the sedatives lorazepam and midazolam and the powerful painkiller morphine.
While the alleged drug tampering happened in 2011, Ferrer said Boston EMS was unable to accurately identify the small number of patients who may have been exposed to compromised medications until the state drug analysis lab completed its testing of medication vials — about 200 samples — at the end of July, 10 months after the problem was first discovered. She said the test results then allowed EMS to identify 64 patients that potentially received compromised medications.
Ferrer said officials still do not know how many of the 64 patients actually received compromised medications, but she said the group represents a very small subset, far fewer than 1 percent of the 16,968 patients encountered by EMS during the time period in question.
She said officials yanked every vial of controlled medications aboard the nine advanced life support ambulances that carried them on Sept. 7, 2011 — a day after the suspected tampering was discovered.
Ferrer said Boston health officials immediately notified the Boston Police Department, state public health officials, and the federal Drug Enforcement Administration.
“Those are the protocols,’’ Ferrer said. “As soon as we determined there was a problem we did what we could do to ensure the investigations that needed to happen were happening.’’
The drug samples were sent to the same state drug analysis lab that was closed in August amid revelations that chemist Annie Dookhan
allegedly altered drug samples, faked drug tests, forged colleagues’ signatures on analysis reports, and lied about having a master’s degree. She was arrested Friday and charged with two counts of obstruction of justice and one count of falsifying her academic records. Investigators say that Dookhan has jeopardized the reliability of drug evidence used in 34,000 cases.
The Boston Police Department declined to comment on whether there are similar concerns over the qaulity of testing on the Boston EMS samples.
Ferrer said this is the first incident of suspected drug tampering in Boston EMS’s 135-year history, and she worried that the case could undermine trust in the department’s 350 paramedics and emergency medical technicians.
“We want to assure the public that this is a service people can rely on that provides life-saving services by a well-trained and skilled work force,’’ Ferrer said.
She said members of the public who have questions about Boston EMS services should contact the central office at 617-343-2367.