PORTLAND, Ore. — The measles outbreak has spread, with three more cases announced in Vancouver on Sunday.

That makes the total number of people with the virus 34, with nine more suspected.

The outbreak is garnering national attention. It was featured on NBC Nightly News last week, and a Harvard researcher has weighted in, telling KGW on Sunday that an outbreak like this was inevitable with the number of people not vaccinated.

RELATED: Clark County measles outbreak: Confirmed cases up to 34, 9 more suspected

"It's of serious concern. I mean the Governor's declaration of emergency was for good reason," said Dr. Marc Lipsitch, a professor of Epidemiology at Harvard.

Lipsitch runs the Center for Communicable Disease Dynamics at Harvard. He said he's not actually studying the outbreak in Washington.

Mark Lipsitch
Dr. Marc Lipsitch, professor of Epidemiology at Harvard

Lipsitch said there's no need to study measles. There's a vaccine. It's preventable.

But Lipsitch said he's watching as a highly contagious but preventable disease works its way through the Pacific Northwest.

"If you allow flammable material to build up, then it doesn't start until there's a spark, but then if there is a spark, it happens," Lipsitch said. "Unvaccinated people are like flammable material."

RELATED: VERIFY: Measles outbreak in Clark County

It's an ironic metaphor when tied to a region routinely ravaged by actual fires. Granted, there's no vaccine for that. There is one for the measles.

Its purpose, thwarted by a growing number who believe a discredited and debunked study out of the UK that falsely warned the vaccine is dangerous. For people like Dr. Lipsitch, who have devoted their career to studying and stopping the spread of diseases, watching this kind of fire grow is frustrating.

"If this were a low-resource country, we would be saying, 'How can we enhance your vaccination program to get you to what the rest of the world is trying to do?' So to have that in a place full of people who have access to the vaccine is just irresponsible," Lipsitch said.

RELATED: Health officials warn Washington measles outbreak will keep growing

Irresponsible — and expensive — for county medical offices.

According to The Columbian, this outbreak has already cost Clark County more than $100,000. Officials warn the cost could reach seven figures.

It's a routine Dr. Lipsitch watched time and again, following outbreaks at Disneyland in 2015 and a record number of cases in Europe last year, in the tens of thousands.

The vast majority, experts say, are courtesy of anti-vaxxer conspiracy theorists. And as Dr. Lipsitch points out, it's putting the innocent at risk.

"Young children, young infants cannot get the vaccine," Lipsitch said. "So even if they have the best of intentions in the world or their parents do, they are at risk from cases of unvaccinated people who could have been vaccinated."

Dr. Lipsitch said he's never met an anti-vaxxer knowingly. But he shared a story about an old classmate, turned physician, who was confused by the then-discredited study.

He said if a doctor was puzzled by the discredited report, people shouldn't blame parents. Instead, he said, blame those spreading the dangerous misinformation.