Islander Celina Yarkin, a mother of three young girls, a farmer and a fixture at her family’s produce table at the weekly Farmers Market, has taken on the issue of the low vaccination rate in Vashon’s children.

Yarkin, who has been interested in immunizations for years, has studied the issue on Vashon and has found statistics that concern public health and school district officials and Yarkin herself.

Vashon, Yarkin’s research shows, has an insufficient number of children vaccinated against whooping cough, measles and polio to ensure what is often called “herd immunity” — enough immunized people to keep diseases from spreading if they enter a community.

Vashon is vulnerable to widespread, severe health problems because of this, Yarkin contends — a situation she wants to change so that this community she loves is more fully protected.

“My goal is to raise the vaccination rates on Vashon,” she said.

To that end, she has created a display about vaccines that is now in the lobby of Chautauqua Elementary School. Below it, she included a notebook for people to comment in and begin what she hopes will be a community conversation about the issue.

It will be a spirited conversation, she is sure.

Vashon has three times more children who are not fully vaccinated than in the rest of the state, according to Dr. Jeff Duchin, the chief of Communicable Diseases and Immunization for Public Health – Seattle & King County.

This low rate did not happen by accident.

Many Island parents question the standard medical regimen of numerous vaccinations in an infant’s earliest years. This debate — and parents’ fears — grew particularly pronounced after 1998, when a British physician reported a link between autism and the measles, rumps and rubella (MMR) vaccine. While many studies have disproved that link, concerns linger about vaccines, leading some parents to believe that the best route for their children’s health is though a healthy lifestyle, minimal vaccination and allowing children’s immune systems to develop naturally in the course of acquiring and fighting off diseases.

But Yarkin says her review of the scientific literature doesn’t bear out the belief that vaccinations can lead to autism or other problems. The risks from the diseases vaccinations prevent, on the other hand, are high, she said.

Yarkin’s large information board has general information about vaccines, a panel dedicated to the measles, mumps and rubella and autism controversy and information specific to Vashon.

Her research shows that for whooping cough, or pertussis, the percent of people that need to be immunized to ensure herd immunity is 92 to 94 percent. Of Chautauqua students, only 85.5 percent are immunized.

For measles, considered by health experts to be one of the most contagious diseases that exists, the range for herd immunity is 83 to 94 percent. Vaccinated Chautauqua students are at 84.8 percent, the very bottom of the range.

Dr. William Foege, an Islander who headed the Centers for Disease Control from 1977 to 1983 and who is credited with devising the strategy to eradicate smallpox, is familiar with Yarkin’s work and supports it. Herd immunity is complex, he said, and fixed numbers are difficult to come by. He boils the issue down to the basics: “Every susceptible child presents a risk.”

Calling immunizing children a “social contract” that people make, he notes that the risk unvaccinated children pose is not just to themselves but to the larger community.

This “social contract” concept lies at the heart of Yarkin’s work.

“It’s not just about individual choice. … The nature of vaccinations is about protecting one another and not just your own children,” she said.

Yarkin, who noted she loves a good debate, expects strong reactions to her project and is ready, with her eyes on is what is for her the bigger picture.

“If we would have an outbreak and lose a child, people will be talking then. … I don’t ever want to have this discussion as a result of tragedy,” she said.

Kate Packard, a nurse with Vashon Island School District, recalls Vashon’s pertussis outbreak in the late 1990s.

“There was tremendous distress on the Island,” she said.

People of all ages became sick, and one infant was hospitalized. Some students at McMurray developed asthma as a result of the illness.

The distress and anger in the community were profound, Packard recalled, with parents of unvaccinated children defensive and parents of vaccinated children irate.

While pertussis is difficult enough and particularly dangerous for babies, measles is a more serious disease, according to Packard.

“For years, I have been worried about the measles,” she said.

On Vashon in 2000, there was a large jump in the number of students whose parents claimed exemptions for the measles vaccine, and the vaccination rate has stayed low since.

Before vaccination, measles was considered a typical childhood illness, Foege said.

Most people recover without lingering health effects, but for some, problems can be severe — pneumonia or encephalitis, which can cause brain damage, for instance. Pregnant women can miscarry or enter premature labor.

Roughly 12 years ago, a measles outbreak occurred in this country, Foege recalled. About 40,000 people got sick; 200 died.

Like Foege, public health’s Duchin would like Vashon’s vaccination rate to rise.

“We want to see children protected. We do not want to see preventable diesases happen to children anywhere in the county,” he said.

No medical intervention is 100 percent perfect, he said, and side effects do sometimes occur with vaccines. But they are typically minor and short-lived, he said: a sore arm, a low-grade fever, a potential allergic reaction.

In the 12 years he has been in his position, he knows of only one severe vaccine-related health problem in the county, and a certain link to vaccination was not definitively established, he said.

But the consequences of not vaccinating are large for many diseases, he noted, and often when illness strikes, some people in the community are affected more than others: babies too young to be immunized, the elderly and those with impaired immune systems.

It was this point, Yarkin said, that she “kept griping about” — and that finally led her to decide to do something about it.

In 2009, she called together a group of national, state and county public health experts and local school officials to address the issue of Vashon’s low vaccination rate.

With information from the Vashon Health Center and the school district and continued research on her part, she set about creating the display last fall in her limited free time.

Word about her has traveled; it is unusual for a mother of three and a farmer to take up the pro-vaccination cause, and she has been noticed in wide circles. Dr. Paul Offet, the Chief of Infectious Diseases and Director of the Vaccine Education Center at The Children’s Hospital of Philadelphia and author of “Autism’s False Prophets,” recently interviewed her and will include the story of her work in his next book.

Yarkin, in jeans and a thick sweater just in from tending her crops, said she would like to go on Oprah with actress Jenny McCarthy, who has a child diagnosed with autism and is an outspoken critic of vaccines.

Ultimately, Yarkin wants the community to know this is not a project she has taken on in a judgmental way. She, too, was leery of vaccines, she said, but through reading and the advice of her scientist husband, who has helped her make sense of some studies, this is the path she has chosen.

“I think it’s really important. This decision is about all of us together,” Yarkin said.