Health officials in one county near Portland, Oregon have declared a public health emergency because of an outbreak of measles that has infected 22 people so far. An outbreak among Orthodox Jews has led to 177 cases in New York, helping make 2018 the second-worst year for measles since 2000, according to the Centers for Disease Control and Prevention.

The outbreaks are sparked by travelers who bring the virus back from other countries, as the virus finds fuel in pockets of unvaccinated people, the CDC says.

“In 2018, 349 individual cases of measles were confirmed in 26 states and the District of Columbia. This is the second-greatest number of annual cases reported since measles was eliminated in the U.S. in 2000. (The greatest was 667 cases reported in 2014),” the CDC says in its latest update on measles.

Measles outbreak update: 22 confirmed cases, 3 suspect cases. Three new exposure locations: Orchards Elementary School, PeaceHealth Urgent Care - Memorial, Dollar Tree (Orchards). Details: https://t.co/hDls0L2GFi — Clark County WA_PH (@ClarkCoWA_PH) January 21, 2019

The worst year was 2014, with 667 cases.

The outbreaks in New York and Washington state began last fall, but they’re still going on. Clark County, bordering Oregon in southwestern Washington, has reported 22 cases. Oregon officials had to warn fans who attended a Portland Trail Blazers game earlier this month about the risk of catching the virus from patient who was in the arena while contagious.

Almost none of the cases had been vaccinated against measles.

People who are fully vaccinated against measles have very little risk of becoming infected. The vaccine provides upwards of 95 percent protection. But measles is one of the most infectious viruses known and will infect 90 percent of unimmunized people who breathe it in.

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Clark County started making robocalls Tuesday to people who can be identified and tracked down, to warn them of the risk. Kids at more than a dozen schools and passengers who passed through the Portland airport are among those who may have been exposed.

The emergency declaration helps move along investigations and warnings, a spokeswoman for the county said. "The emergency declaration enables us to seek resources (such as nurses, epidemiologists) outside of our regional area and existing mutual-aid agreements," she said.

On both coasts, the outbreaks have been fueled by communities that have resisted vaccination for years. Vaccination rates have fallen in Washington state. In 2015, 77 percent of kids were completely vaccinated, but that dropped to 75.7 percent in 2016, according to state data. Clark county falls at the lower end, although some counties have vaccination rates of below 70 percent.

Just 1 percent of kids who were exempted from vaccination last year in Washington were excused for medical reasons. The rest got religious or philosophical exemptions.

According to a recent Blue Cross Blue Shield report, New York state has a high rate of vaccine refusal. Unvaccinated people may escape infection thanks to what’s known as herd immunity in their communities, until someone carries a germ from somewhere else.

Many, if not most, kids are under-vaccinated because their parents cannot or do not get them pediatrician or clinic visits on time. But the increasingly loud and growing anti-vaccination and vaccine skeptic movements are feeding parental fears and growing pockets of resistance.

Earlier this month, the World Health Organization said anti-vaccination movements are among 10 threats to global health in 2019. “Measles, for example, has seen a 30 percent increase in cases globally. The reasons for this rise are complex, and not all of these cases are due to vaccine hesitancy. However, some countries that were close to eliminating the disease have seen a resurgence,” WHO said in its report.

Distrust of vaccines is behind outbreaks among Jewish communities in and around New York City, local health officials say.

“As of January 16, 2019, there have been 58 confirmed cases of measles in the Orthodox Jewish community in Brooklyn since October,” the New York City health department says on its website. Nearby Rockland County has 116 confirmed cases, the county health department said.

“Several of those people have had complications, including hospitalizations and premature labor,” the department said.

Epidemics of measles in Israel and Ukraine are the source of the infection.

“The initial child with measles was unvaccinated and acquired measles on a visit to Israel, where a large outbreak of the disease is occurring. Since then, there have been additional children from Brooklyn who were unvaccinated and acquired measles while in Israel,” the New York City health department said.

2018 saw the 2nd-greatest annual number of US #measles cases since 1996. 1 reason: 81 unvaccinated travelers (mostly US residents) got measles abroad & brought it to the US where it spread. Ensure you’re protected against measles before traveling. https://t.co/czlSryEK9e pic.twitter.com/OLuXPBQ3JI — CDC (@CDCgov) January 18, 2019

Although some people argue that measles is a relatively harmless childhood illness, it can kill. Measles causes encephalitis and pneumonia and before mass vaccination began in the 1980s, measles killed nearly 2.6 million people a year, according to the World Health Organization. It still kills more than 100,000 people a year, mostly children under five. One in 1,000 people who catch measles die of it.

“While global measles deaths have decreased by 84 percent worldwide in recent years — from 550,100 deaths in 2000 to 89,780 in 2016 — measles is still common in many developing countries, particularly in parts of Africa and Asia. An estimated 7 million people were affected by measles in 2016,” WHO said.

Europe had close to 60,000 measles cases last year. Brazil had more than 10,000 cases. Travelers to and from heavily affected countries can carry the virus back and infect others before they even start showing symptoms.

“Eighty-one people brought measles to the U.S. from other countries in 2018. This is the greatest number of imported cases since measles was eliminated from the U.S. in 2000,” the CDC said.

“Traveling to Israel or Ukraine, where another large outbreak is occurring? Make sure you are vaccinated against measles before departure.”