The measles outbreak in New Zealand has spread to Colorado, according to US health officials.
On Tuesday The Denver Post reported three children who travelled from New Zealand to Denver via Los Angeles last week have been hospitalised due to measles.
The Center for Disease Control and Protection (CDC) warned travellers in Denver and Los Angeles they could be at risk of contracting measles.
"It's very concerning for people to be in close proximity of measles," said CDC spokesperson Scott Pauley.
Officials say anyone who visited Denver Airport between 1:15pm and 5:45pm on 11 December are at risk of measles.
People who were at Children's Hospital Colarado's Anschutz Campus Emergency Department between 1pm and 7:10pm the following day could also have been exposed.
The New Zealand measles epidemic broke out in January 2019. To date there have been 2172 cases across the country with 1726 of these cases in Auckland.
The disease spread to Samoa where it has killed 72 people in two months. The majority of the dead are children and babies.
Last week, the Ministry of Foreign Affairs and Trade confirmed New Zealand as the likely source of the Samoan measles epidemic.
"International travel means that measles can spread quickly from country to country," a spokesperson told RNZ.
"It is highly likely that New Zealand is the main source for the outbreak in Samoa."