Update on vaccine breakthrough cases in Washington state


Contact: DOH Communications 
Public inquiries: State COVID-19 Assistance Hotline, 1-800-525-0127

OLYMPIA – The Washington State Department of Health (DOH) is reporting a total of 217 COVID-19 vaccine breakthrough cases among vaccinated individuals in Washington state as of April 3, 2021. That is an increase from the 102 cases we first reported on March 30, 2021. Breakthrough cases have now been identified in 24 of Washington’s 39 counties.

Vaccine breakthrough occurs when a person tests positive for COVID-19 two weeks or more after receiving the full course of an approved COVID-19 vaccine. Large-scale clinical studies found that COVID-19 vaccines prevented most people from getting COVID-19 illness. However, the vaccines are not 100% effective. This means a very small number of fully vaccinated people will still get sick with COVID-19. Scientists note that breakthroughs are expected with any vaccine.

To date, more than 1.7 million people have been fully vaccinated in Washington state. The breakthrough cases represent a small portion, about .01 percent, of the fully vaccinated population.

DOH is investigating a total of five suspected deaths of individuals who experienced vaccine breakthrough. The people who died were between 67-94 years old and all had multiple underlying conditions. Four were residents of long-term care facilities.

In Washington state, the median age of those with confirmed vaccine breakthrough has shifted downward since the first cases were reported, with more people in the 40-59 year old demographic compared to previous weeks. Some breakthrough cases sent for sequencing showed evidence of variants.

While the majority of individuals with confirmed vaccine breakthrough experienced only mild or no symptoms, some people have been hospitalized. DOH is still gathering information for approximately half of the breakthrough cases. However, the agency can say that among breakthrough cases with hospitalization information available, 12% were hospitalized.

A person is confirmed with vaccine breakthrough if they test positive for COVID-19 using a PCR test or antigen test and received their final dose of the COVID-19 vaccine more than two weeks prior to the positive test. Additional investigations help us better understand clinical and outbreak information when vaccine breakthrough happens.

"Finding evidence of vaccine breakthrough cases reminds us that, even if you have been vaccinated, you still need to wear a mask, practice social distancing, and wash your hands to prevent spreading COVID-19 to others who have not been vaccinated," said Umair A. Shah, MD, MPH, Secretary of Health. "We encourage everyone to get vaccinated as soon as they are eligible, and encourage friends, loved ones, and co-workers to do the same."

The Department of Health will provide a regular report regarding vaccine breakthrough in Washington state beginning in late April.

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