Four Oregonians have tested positive for COVID-19 after being vaccinated against the disease, Oregon health officials disclosed Friday.
The Oregon Health Authority said two of the cases were in Lane County and two were in Yamhill County.
Two of the cases were found during routine surveillance testing. The other two appear to be connected. OHA officials did not specify which two.
“This is a serious but not surprising development,” OHA director Patrick Allen said.
These re-infections, called “breakthrough infections,” are infections that occur more than 14 days after receiving the second dose of vaccine.
Given the effectiveness rate of the two vaccines —95% for both Pfizer-BioNTech’s and Moderna’s — it’s inevitable that some of the 177,000 vaccinated Oregonians would become reinfected.
It isn’t yet known if these four known reinfection cases involved a newer variants of the coronavirus. The Oregon Health Authority is attempting to get samples from these patients to be tested, a process that could take over a week.
The Centers for Disease Control and Prevention is gathering data on COVID-19 breakthrough cases, but they have yet to make that data public. Oregon is one of the first states to participate in their genomics surveillance program, and has sent information about these cases to the CDC.
Many breakthrough cases were reported during the Moderna and Pfizer COVID-19 vaccination trials. Those cases tended to be asymptomatic or mild, and so far, Oregon’s cases fall into either of those two categories.
State epidemiologist Dr. Dean Sidelinger said that’s good news, considering the COVID-19 death toll for non-vaccinated Oregonian is close to 3,000.
“Vaccines keep you from getting seriously ill, even if you don’t get sick,” he said.
Sidelinger said these breakthrough cases underscore the importance of continuing to follow pandemic safety measures like wearing masks and socially distancing even after receiving the vaccine. Until enough vaccinations have been administered to achieve herd immunity — something that is still months away — breakthrough cases will continue to happen.