PORT ANGELES — A Port Angeles man related to people who caught measles this year has come down with the highly contagious disease despite having been vaccinated at least 44 years ago.

The case is the fifth confirmed in Clallam County since Feb. 1. No cases have been confirmed in neighboring Jefferson County.

No age was provided for the man, who had been considered immune because he was vaccinated against the disease decades ago.

It is the first case in Clallam County reported in an inoculated person.

Public health authorities said he had quarantined himself during the time he would have been contagious, so he had had no contact with susceptible people.

Nevertheless, the case widens the window of possible infection — the time during which public health officials could expect more cases — to April 19, health officials said.

After the fourth case was diagnosed in late February, officials said the window of contagion would close April 6.

The man whose infection was confirmed by a state lab test late Thursday had been inoculated with the vaccine used between 1957 and 1971.

That vaccine does not protect people as well as present immunizations, health authorities said.

Clallam County Health and Human Services Iva Burks urged adults who have had a single shot of the old vaccine, as well as any who are unvaccinated, to come to no-cost clinics Monday, Thursday and Saturday.

The man suffered an onset of the ailment’s telltale rash March 4, Burks said.

The first in a string of measles cases in Clallam County was a 52-year-old man who was hospitalized Feb. 1 in Olympic Medical Center in Port Angeles and has since recovered.

A second man, 43, and a 5-year-old girl caught measles after exposure to that patient.

A 14-year-old sibling of the kindergarten girl contracted measles after exposure to her.

The latest patient was a relative of two of the people who have had measles in Clallam County this year. Burks declined to specify which ones due to federal health-privacy regulations.

Earlier, a juvenile who had received the modern measles, mumps, rubella (MMR) vaccine developed a rash that was found not to be actual measles. Instead, it was a reaction to the vaccine.

The current measles vaccine is highly effective, said Dr. Jeannette Stehr-Green, interim Clallam County health officer.

People who receive a single MMR shot have a 95 percent chance of immunity, she said, and those who receive a recommended second shot have a 97 percent to 99 percent chance of immunity.

Children should receive the first dose at 12-15 months of age and the second when they are between 4 and 6 years old, authorities said.

Adults born after 1957 should have at least one vaccination. Some people, including health care workers, should receive a second dose.

“It is vital to get vaccinated to protect yourself and your family against measles as well as those who cannot be vaccinated, including babies, pregnant women and immune-suppressed people,” Stehr-Green said.

Seven cases of measles have been reported statewide. Two were in Grays Harbor County and one in Whatcom County.

The federal Centers for Disease Control and Prevention says 173 people in 17 states caught the disease between Jan. 1 and March 6.

Of those, 127 cases are linked to an outbreak that began in Disneyland.

Clallam County measles are not linked to that outbreak, officials have said, but rather are a type of measles common in Asia and the Philippines.

For more Clallam County information, see http://tinyurl.com/PDN-measlesalerts.

For more in Jefferson County, visit www.jeffersoncountypublichealth.org.