Cases of COVID-19 vaccine breakthrough confirmed in Washington state

April 1, 2021

The Washington State Department of Health (DOH) is investigating reports of people in the state who tested positive for COVID-19 more than two weeks after being fully vaccinated. Scientists call these “vaccine breakthrough” cases, which are expected with any vaccine, according to a news release from the department.

Large-scale clinical studies found that COVID-19 vaccines reduced the risk of getting COVID-19 in vaccinated people by up to 95% compared to people who did not receive the vaccine. However, the vaccines are not 100% effective in preventing infection. This means a small percentage of fully vaccinated people can be expected to still get COVID-19. These are identified as breakthrough cases.

Out of one million fully vaccinated individuals in Washington state, epidemiologists have reported evidence of 102 breakthrough cases since February 1, 2021, which represents .01 percent of vaccinated people in Washington. Breakthrough cases have been identified in 18 counties. The majority of those in Washington state with confirmed vaccine breakthrough experienced only mild symptoms, if any.

However, since February 1, eight people with vaccine breakthrough have been hospitalized. DOH is investigating two potential vaccine breakthrough cases where the patients died. Both patients were more than 80 years old and suffered underlying health issues. Further investigation will help to identify patterns among people who have COVID-19 after vaccination, such as if a virus variant may have caused the infection.

DOH confirms a breakthrough case with a positive PCR test or Antigen test in a person more than two weeks after he or she has received their final dose of the COVID-19 vaccine. Additional investigations help determine clinical and outbreak information.

Visit the Washington State Department of Health for more news