As we climb to ever higher case counts in the 2019 measles outbreaks, you might be wondering who to blame?
Who started the outbreaks?
How Does ‘Patient Zero’ Start a Measles Outbreaks?
As you have likely guessed, there is no one person who started all of this year’s outbreaks. Well, maybe there is. After
In most cases though, we do know who started the outbreak – the “patient zero.”
And it is almost always an unvaccinated traveler, typically a US resident, who got measles abroad and brought it back into the U.S.
What happens next? If they expose a lot of people in an area with low vaccination levels, then you can expect a big outbreak. On the other hand, if most people are vaccinated and protected, you might not see any more cases in that area.
Who Is ‘Patient Zero’ in the 2019 Measles Outbreaks?
So who are these folks?

They aren’t people who had been recently vaccinated are giving others vaccine strain measles through shedding! That doesn’t happen.
Instead, at least 44 people triggered separate outbreaks after traveling from the Philippines, Ukraine, Israel, Thailand, Vietnam, Germany, Algeria, France, India, Lithuania, Russia, and the United Kingdom.
The 2019 measles outbreaks include the:
- Rockland Outbreak – an unvaccinated teenager brought measles to Rockland County in September 2018 from Israel.
- Brooklyn Outbreak – the initial case in Brooklyn was unvaccinated and got measles in October 2018 on a visit to Israel. Measles was reintroduced into the community at least six other times though, four cases were also acquired on visits to Israel, while two people got measles from the U.K., and one from Ukraine.
- Pacific Northwest Outbreak – a child who had traveled from Ukraine to Washington was the first confirmed case and likely source of the Pacific Northwest measles outbreak.
- Michigan Outbreak – a traveler from Brooklyn started the Michigan measles outbreak.
- Northern California Outbreak – a “cluster” of cases in Butte, Tehama, and Shasta counties that was started by a traveler who had recently been to the Philippines.
- Puget Sound Outbreak – triggered by a Canadian resident who traveled to Seattle, after completing a trip to Japan and New York, where he likely became infected.
Why is it important to find patient zero and know who started an outbreak?
Mostly, it helps you find everyone who was exposed to measles and hopefully limit and quickly control the outbreak.

It should also remind everyone that the easiest way to avoid getting measles and avoid triggering an outbreak, is to get vaccinated and protected, especially if you plan on traveling out of the country.
More on Who Is ‘Patient Zero’ in the 2019 Measles Outbreaks?
- Japan’s Rubella Outbreak Should Be a Warning About What Could Happen Here
- Who Dies with Measles?
- How Can the Unvaccinated Spread Diseases They Don’t Have?
- How Do They Figure out Who Starts an Outbreak?
- Is a Vaccine Strain Causing The Latest Measles Outbreak?
- Can MMR Shedding Start a Measles Outbreak?
- MMWR – Increase in Measles Cases — United States, January 1–April 26, 2019
- MMWR – Notes from the Field: Measles Outbreaks from Imported Cases in Orthodox Jewish Communities — New York and New Jersey, 2018–2019
- Unaware he had measles, a man traveled from N.Y. to Michigan, infecting 39 people
- Measles Information for Providers (NYC)
- Health Department Issuing Civil Summonses to Three People for Failing to Comply with
Commissioner’s Emergency Vaccination Order During Measles Outbreak (Brooklyn Outbreak) - Measles in Butte County, not Over Yet
U.S. sees most measles cases since it was eradicated; local cases traced toPhilippines (Northern California Outbreak)