As more and more parents choose to skip vaccinations for their children, public health professionals and researchers have been looking at new ways to ease the concerns of parents who are hesitant.

But that turns out to be tough to do. Studies have found that simply educating parents about the safety and efficacy of vaccines doesn't increasethe likelihood that they will get children vaccinated.

Since numerous studies show that doctors are the most trusted communicators of information about vaccines, the Group Health Research Institute in Seattle wanted to see if it would help to train doctors and other providers on how they communicate with mothers hesitant about vaccines.

"The intervention was designed to involve parents and respect where they were coming from, respect that they wanted what was best for their child and the provider wanted that, too," said the study's lead author, Nora Henrikson, a research associate with the institute. The goal, she said, was to help doctors address parents' concerns but "still make a strong recommendation for vaccines."

It was a lofty goal, but the upshot is this: It didn't work.

There was no sign that what the researchers did in the study helped to reduce vaccine hesitancy.

But that's doesn't mean the end of this approach.

Scientists like to say that finding out that something doesn't work can be just as important as finding out what does. Both researchers involved with the study and those who had nothing to do with it say that's the case here.

Let's look first at what Group Health Research did in its study, what they say is the first randomized trial to test improving hesitancy about vaccination by directly targeting doctors.

The centerpiece of the approach was a 45-minute training session with doctors and other health care providers. Participants also received written support material, monthly emails and assistance upon request.

The parents themselves did not receive training. The goal was to see if giving doctors better communication skills would reduce hesitancy in mothers.

In the study, 347 mothers of healthy newborn babies were randomized into two groups. Some received care in clinics where doctors had received the training, and the rest went to clinics where they had not.

Vaccine hesitancy declined somewhat in both groups over the six months of the study, but there was no statistically significant difference between the groups. During the study period, there was a whooping cough outbreak in Washington, as well as a new law requiring a doctor's note to opt out of vaccines, and the decline in vaccine hesitancy may have been related to those events, rather than anything in the study.

The study was published in the journal Pediatrics and was funded by the Group Health Foundation and the Bill and Melinda Gates Foundation.

"Obviously we were hopeful that it would improve vaccine hesitancy, so we would have preferred to see a different effect," Henrikson said, "but it really raised more questions about what other projects we could do moving forward."

Brendan Nyhan, a professor of government at Dartmouth who studies communication about vaccines, was positive about the research despite the lack of impact.

"We're headed in the right direction," he said. "We're starting to ask better questions, and part of real science is that sometimes our experiments don't work out the way we expect."

The study "required careful consideration and should be seen as the start, not the end of the story," according to an accompanying editorial by Julie Leask, an associate professor at the University of Sydney's School of Public Health who studies vaccine attitudes, and Dr. Paul Kinnersley, a professor at the Institute of Medical Education at the University of Cardiff, Wales, who teaches medical students how to talk to patients. It pointed to a "clear need to develop new approaches to vaccine consultation," they wrote.

One of Henrikson's big questions is whether the 45-minute training session was "a big enough dose of the intervention. It's not a bad intervention," she said. "But a more intense version of it might be able to make a difference."

Since the overwhelming majority of parents do vaccinate their children, Henrikson said another area for future research could be identifying ways to "help providers make time for parents who do have more questions and need more time."

Concerns about vaccines are not an all-or-nothing proposition, Henrikson said; it's a continuum. On one end are people who support vaccines and make sure their children receive all recommended vaccinations. On the other end are people who refuse all vaccines. "Then there are people in between," she said, "and we're still understanding that, and at what point do people really have all the information they need?"

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