After many years with high numbers of students not fully vaccinated, the Vashon Island School District has seen a significant decrease in the number of kindergartners with vaccine exemptions this year.

School district nurse Sarah Day, who recently compiled and analyzed this school year’s vaccine statistics, said last week that the kindergarten exemption rate dropped from 22 percent last year to 12 percent this year.

“That is a big drop. We had a lot of dropping to do,” she said.

Day said she and others at the district are not yet sure what caused the decline in the number of families refusing vaccines, but wonder if last year’s multi-state measles outbreak is one of the factors, particularly because several news outlets, including The New York Times, called the island out for its high numbers of students not fully vaccinated.

Reached last week, Dr. Jeff Duchin, health officer and chief of communicable disease at Public Health-Seattle & King County, welcomed the news.

“I am very, very proud of the people on Vashon. I hope it indicates a trend to getting our kids better immunized,” he said.

Duchin said he had not heard reports from individual districts or schools to know yet if Vashon’s increase in vaccinated students is part of a larger trend this year, but he said that information will be available  from Washington’s Department of Health later this spring.

In the meantime, to gather insight about what’s behind this year’s increase, Celina Yarkin, who has worked over the past several years to increase vaccination rates on the island, said she will create a poster for Chautauqua that will include a simple survey to gather information on what spurred the change this year.

The poster, which she expects to be completed within a few weeks, will likely include some suspected reasons as possibilities for the increase in vaccines, as well as  space for comments about people’s own perceptions and knowledge.

“There is a lot of conversation that happens out there … and it would be great to find out what other people know about what might have changed this year on the island,” Yarkin said.

In addition to the improved kindergarten exemption rate, Day said the vaccine picture is improving overall in the schools.

The illness that has caused the most concern at the district is measles because it is highly contagious and carries a high risk of complications.

This year, Day said, at Chautauqua — the school with the highest rate of exemptions — nearly 91 percent of the students are fully vaccinated against the measles. That is up from 84 percent in 2013 and better than any year since 1990, but still shy of the desired 94 percent needed to prevent a  community outbreak.

Pertussis, or whooping cough, is another of the most worrisome diseases because it is especially dangerous for infants, and is common, with peaks in reported cases every three to five years.

This year, 88 percent of Chautauqua students have been vaccinated against it, compared with just 67 percent in 2012 and 85 percent in 2009.

Day noted that the pertussis vaccine picture is mixed, as recent research has shown the current Tdap booster given to teens provides only short-term immunity.

A recent article she provided from  the journal Pediatrics indicates that the vaccine’s protection drops sharply after the first year, and little protection remains just three years later.

Public health’s Duchin also acknowledged the problems with the vaccine.

“It is not as effective as we would like or need it to be to get rid of pertussis,” he said.

However, he noted that the vaccines continue to protect the most vulnerable age group — babies from 6 to 12 months old — and that the shortcomings are seen more in older children.

The vaccine is most helpful, he said, when given to pregnant women in their third trimester. They develop immunity, and then pass it on to their babies, where it protects them in the first few months of life.

He stressed the vaccine is the best option currently available.

“Although it is far from perfect, it is still very much worth doing,” he said. “A few years of protection is better than no protection.”

Noting that the topic of vaccines can be divisive, Day encouraged relying on scientifically sound information and having  courteous conversations even when views differ.

“Continue to be respectful,” she said. “I do not want to shut doors on people. I want people to feel like they can ask questions.”