BOSTON – Born in an era when vaccine-preventable diseases are rare, newly minted physicians appear to have less faith in the efficacy and safety of vaccinations than do their older colleagues – and this skepticism may rub off on patients, with potentially harmful consequences, said investigators at the annual meeting of the Infectious Diseases Society of America.

Recent medical school graduates were about 15% less likely to say that vaccines are efficacious than were their more mature counterparts. The younger providers also were less likely to say they believe that live attenuated or inactivated vaccines against poliomyelitis, measles, mumps, rubella, and varicella were safe, and more likely to say that vaccines do more harm than good, said Dr. Saad B. Omer of the Rollins School of Public Health at Emory University, Atlanta, at a briefing and in a poster to be presented Oct. 21.

Overall support for vaccinations among physicians of all ages is generally strong, Omer said. But the data reveal trends that seem to mirror those seen among parents. Younger physicians, like younger parents, rarely encounter once-commonplace childhood ailments, and therefore may be less sanguine about the benefits of immunization than more seasoned providers, Dr. Omer noted.

"If you are a health care provider, and you have seen a case of whooping cough and have heard a child whoop, or if you have treated Haemophilus influenzae B meningitis, that experience is a little more visceral; and that possibly could have an impact not only on the individual level, but also at the institutional level in terms of training," he said.

In terms of parent and physician attitudes, vaccinations have been victims of their own success, suggested Dr. Bruce Gellin of the National Vaccine Program Office at the U.S. Department of Health and Human Services.

"I think it reflects the power that vaccines have had to make these diseases go away, which now [calls into question] their ‘value’ to the people who are receiving them, because they don’t understand how society has changed because of them," Dr. Gellin said.

"As the familiarity with the disease goes away, then [providers] are only hearing about vaccines and don’t link up with what the vaccines are designed to do," noted Dr. Gellin while moderated a briefing at which the data were presented.

To gauge physician attitudes, Dr. Omer and his colleague Michelle J. Mergler of the National Vaccine Program Office at the U.S. Department of Health and Human Services surveyed physicians who had been identified by parents participating in a vaccine attitudes survey. The children were either fully vaccinated or had parents who were vaccine refuseniks, choosing to opt out of their schools’ immunization requirements.

A total of 551 providers (84.3% response rate) returned completed surveys. The responses were stratified by physicians caring for vaccine-exempt and nonexempt patients, and by year of graduate clinical training in 5-year intervals, from 1954 through 2002.

The researchers found that every 5-year increase in the graduation date was associated with a 20% increase in the odds ratio (OR) that physicians would agree with the statement that "children get more immunizations than are good for them."

In addition, for every 5-year-later graduation date, there was a 20% decrease in the OR that providers would agree with the statement that "immunizations are getting better and safer all the time as the result of medical research."

Parental Attitudes

In a second study, Dr. Thomas Tryon and his colleagues from Children’s Mercy Hospitals and Clinics in Kansas City, Mo., surveyed 909 pediatricians in nine Midwestern states about patients’ reasons for refusing or questioning vaccinations.