The five measles cases reported in Penobscot County in February — the first in Maine since 2019 — have been contained and have not spread, Maine health officials said on Thursday.

Maine reported a measles case on Feb. 6, followed by four additional cases on Feb. 17 that were considered “close contacts” of the original case, according to the Maine Center for Disease Control and Prevention.

The 21-day incubation period that public health officials were monitoring ended on Monday, said Sara Robinson, an epidemiologist with the Maine CDC. Robinson said during that period people exposed to measles would start showing symptoms if they had contracted the disease.

Robinson said quick action by health officials and cooperation by those who were infected helped prevent spread of the disease.

“People listened, and did what we asked them to do,” Robinson said. “Contacts who needed to quarantine did go ahead and quarantine. That was really helpful in a situation like this.”

Robinson said Maine CDC officials identify and contact those who might have been exposed to measles. The measles vaccine can prevent an infection in an unvaccinated person if given within 72 hours of exposure, Robinson said. If the exposed person has already been vaccinated, they are protected from the virus and don’t need to quarantine, she said.

The cases reported on Feb. 17 were among unvaccinated people. The vaccination status of the first person was “undetermined,” Maine CDC officials have said. Maine’s high vaccination rates and alerting the public to exposure sites also helped limit cases, Robinson said.

Measles symptoms include a rash, fever, cough, runny nose and red, watery eyes. The virus spreads through the respiratory system.

Nationwide, the U.S. Centers for Disease Control and Prevention reported 1,281 cases this year as of March 5, with outbreaks in states like South Carolina and Utah.

With tourist season coming up, the risk to Maine of seeing more cases is high, Robinson said.

“As measles continues to circulate in the nation, people traveling to and from Maine will pose a risk, especially in places like airports,” Robinson said.