The fourth Jefferson County resident to die from COVID-19 had been vaccinated against the disease and passed away while being treated at the University of Washington Medical Center.

The deceased patient was a woman in her mid-60s, Jefferson County Public Health Officer Dr. Tom Locke said in an email to The Leader Thursday.

The woman passed away "after a prolonged hospitalization for respiratory failure due to COVID pneumonia," Locke wrote.  

The woman had "serious underlying health conditions including a lymphatic malignancy that required ongoing chemotherapy and immunosuppressing medications," Locke added. 

Locke said the health department's investigation indicated that the woman was exposed to COVID while she was outside the state of Washington.

"She was appropriately vaccinated, starting in March, but appears to have developed COVID infection shortly after her second vaccine dose," Locke noted.

"Unfortunately, most vaccinations, including the new COVID vaccines, are ineffective in those who are profoundly immunosuppressed. People who have impaired immune function are at high risk for COVID complications should they become infected," he said.

Jefferson County's fourth death from COVID-19 was reported Wednesday by  Jefferson County Public Health.

The coronavirus-related death was the first in Jefferson County since April 19.