After an outbreak of measles last fall, Washington state health officials hoped that a small subset of parents would change their minds about getting their kids immunized. But those parents weren’t moved. In fact, looking at the latest reports of vaccine rates, health officials found that even more parents statewide are foregoing the whooping cough and measles, mumps and rubella (MMR) vaccines. “It's a real puzzle for us why people haven't responded better to the news about this disease,” said Paul Throne of the state Office of Immunization and Child Profile. He thought the news reports would have scared parents. Rather, studies found the dire news appears to have emboldened them. Parents are also increasingly opting out of the polio vaccine. Seventeen years ago, 95.4 percent of kindergarteners in Washington state were vaccinated for polio.

This year, 88.4 percent had the vaccine. It’s even more dramatic in Seattle, where 81.4 percent of kindergarteners have been vaccinated for polio. That’s lower than the 2013 polio immunization rates for 1-year-olds in Zimbabwe, Rwanda, Algeria, El Salvador, Guyana, Sudan, Iran, Kyrgyzstan, Mongolia and Yemen, among other countries, according to data from the World Health Organization. “We're concerned because we need to have about 95 percent of those kids vaccinated to protect everybody else who can't be vaccinated for medical reasons or because they're too young,” Throne said. KUOW interviewed about a dozen parents last fall about why they chose not to give their kids all or some vaccines. Julia Marks of Maple Leaf said she worried too many vaccines are given to infants at once. She said she believes some vaccines could be saved for older children.

"Polio is nonexistent in the states – so if you’re going to travel, it makes sense to do it," Marks said when interviewed last fall. "We are doing vaccines based on our family’s needs, not based on what doctors say we need to follow." Throne believes all children should be fully vaccinated according to the schedule set forth by the U.S. Centers for Disease Control and Prevention. But he agreed it would be unlikely for polio to spread here in Seattle. Just three countries, Nigeria, Afghanistan and Pakistan, still have active cases of polio. Still, those parents are taking a gamble, he said. Although polio has been nearly eradicated across the world, international travelers and immigrants could be carriers of the virus. After all, international travel was the source of most measles cases here. An outside source is also likely how four Amish children in Minnesota contracted polio in 2005. The children, who were unvaccinated, were carrying a strain that had been lingering around for about two years, according to the Centers for Disease Control. An investigation determined the source of the virus likely came from another country. “It's a reality that polio could return if we don't succeed in eliminating it,” Throne said. “Vaccination is the only tool we have to make sure that happens.”