The federal Centers for Disease Control now estimates that surgeons and dentists may have transmitted the AIDS virus to more than 100 Americans in the past decade.
The CDC, admitting its figures are based on broad assumptions, estimates that surgeons have infected between three and 28 patients and that dentists have passed the virus to between 10 and 100 patients.
So far, the agency knows of only three patients who have been infected during medical procedures. All were apparently infected by Dr. David Acer, a Florida dentist who has since died of acquired immune deficiency syndrome.
But, noting that people can harbor the virus for many years before developing symptoms of AIDS, the agency said that many patients who may have been infected during medical procedures would not know it.
The projections appeared in a draft report dated Jan. 30 that was mailed to people planning to attend a Feb. 21-22 conference in Atlanta on the prevention of AIDS and hepatitis during medical procedures.
Doctors and dentists, caught off-guard by the estimates, said yesterday they could not comment on their validity without taking more time to digest the report, which consists of 16 pages of statistics and mathematical formulas.
But many said that practitioners who wear masks, gloves and gowns while using sharp instruments pose an extremely remote risk to their patients -- smaller than other risks encountered in everyday life.
"People are screaming for some sort of political action," said Dr. John Bartlett, chief of the infectious disease division at the Johns Hopkins School of Medicine. "The lay public has to be aware of what we're talking about. Even with these numbers, you still have a greater risk of getting murdered if you live in the city of Baltimore than of getting HIV [the human immunodeficiency virus] if you're operated on."
The CDC estimated that:
SG * The possibility that an HIV-infected surgeon will transmit the vi
rus to a patient during an operation ranges from 1 in 41,667 to 1 in 416,667.
* The chance of an infected dentist transmitting the virus to a patient during a procedure where bleeding is likely ranges from 1 in 263,158 to 1 in 2.6 million.
* An infected surgeon stands a 1.2 percent chance of passing the virus to at least one patient during a year, if he performs 500 procedures. The possibility that he will infect a patient during a seven-year span is 8.1 percent.
The CDC has reports of 42 surgeons with AIDS -- many of whom may now be dead -- and it estimates that 336 have been infected with the virus. Also, it knows of 156 dentists with AIDS and projects that 1,248 are infected with the virus.
Following the upcoming Atlanta conference, the CDC is expected to
issue new guidelines concerning health care workers who carry the virus.
Many hospitals and medical organizations hope the agency will settle several questions: whether infected doctors should continue to operate; whether they should disclose their infection to patients; and whether all doctors should be tested routinely for the virus.
Fueling the growing debate was the death of Dr. Rudolph Almaraz, an accomplished cancer surgeon at Hopkins, from AIDS on Nov. 16.
He operated on an estimated 1,800 patients, and the CDC is expected to launch a study soon to determine whether any contracted the virus from him.
Dr. Bartlett said the risk of contracting the virus from an infected surgeon is so small, according to the CDC estimates, that patients should
be more concerned about other things before entering surgery -- such as the surgeon's competence, whether he abuses drugs and whether the doctor is tired because he has been performing surgery all night.
Dr. Roger Eldridge, assistant professor at the University of Maryland School of Dentistry, said he is convinced that the risks of catching the virus during a dental procedure are infinitesimal as long as the dentist wears gloves, goggles, a gown and a mask.
"The great hazard in all of this is the public stopping to receive dental care for fear they are going to receive an infection," he said. "I don't think we're anywhere near that."