MIAMI, FL - JUNE 02:  A dose of measles vaccine is seen at the Miami Children's Hospital on June 02, 2014 in Miami, Florida. The Centers for Disease Control and Prevention last week announced that in the United States they are seeing the most measles cases in 20 years as they warned clinicians, parents and others to watch for and get vaccinated against the potentially deadly virus.  (Photo illustration by Joe Raedle/Getty Images)
CDC: US could lose measles elimination status
01:38 - Source: CNN
CNN  — 

Three unvaccinated children with measles likely exposed travelers at Denver and Los Angeles airports to the virus, health officials have warned.

The children were visiting from New Zealand and traveled through the Denver International Airport and Los Angeles International Airport on the same day, US Centers for Disease Control and Prevention press officer Scott Pauley told CNN.

Travelers who visited the Denver airport’s Concourse A, train to baggage claim, west baggage claim and west level 4 passenger pick-up areas between 1:15 p.m. and 5:45 p.m. on December 11 could’ve been exposed to the virus, Colorado’s Tri-County Health Department reported.

Los Angeles County health officials issued a similar warning for passengers who visited Terminals 4 and 5 between 6:50 a.m. and 12 p.m. on the same day.

The CDC is contacting passengers who flew on the same planes as the infected children about potential exposure, Pauley said.

The children are being treated at Children’s Hospital Colorado in Aurora while health officials work to identify people who were exposed to the virus since the children landed.

Measles and travel

The highly contagious measles virus was previously thought to be eradicated from the US but it’s still commonly found in Europe, Asia and Africa, according to the CDC.

Most recent measles cases in the US originated in an unvaccinated travelers visiting from abroad, according to the CDC.

The close quarters conditions of air travel are opportune for virus transmission, since about 90% of people who are not immune to measles and come close to an infected person will become infected. But the CDC says the overall risk of contracting a contagious disease on a plane is low.

Passengers sitting in “contact zones” are at risk, though. This includes people sitting in the same row as the infected passengers plus two rows ahead and behind. Children under age 2 are considered vulnerable to the virus no matter where they sat on the plane.

At least 1,261 people have been infected with measles in the US this year, according to the CDC. Most of the outbreaks occurred in “underimmunized, tight-knit communities” including two outbreaks in Orthodox Jewish communities in New York.

CNN’s Cheri Mossburg, Michael Nedelman and Jamie Gumbrecht contributed to this report.