Four Oregonians tested positive for COVID-19 after being vaccinated against the disease, Oregon health officials announced Friday.
The Oregon Health Authority said two of the cases were in Lane County and two in Yamhill County.
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Two of the cases were found during routine surveillance testing. The other two seem to be linked. OHA officials have not specified which two.
“This is a serious but not surprising development,” said OHA Director Patrick Allen.
These reinfections, called “breakthrough infections”, are infections that occur more than 14 days after the second dose of vaccine.
Given the effectiveness of the two vaccines – 95% for both Pfizer-BioNTechs and Moderna – it is inevitable that some of the 177,000 Oregonians vaccinated would become reinfected.
It is not yet known whether these four known cases of re-infection were a newer variant of the corona virus. The Oregon Health Authority is trying to get samples from these patients tested, a process that can take more than a week.
The Centers for Disease Control and Prevention is collecting data on breakthrough cases of COVID-19, but they have yet to make that data public. Oregon is one of the first states to join their genomics surveillance program and has sent information on these cases to the CDC.
Many breakthrough cases have been reported during the Moderna and Pfizer COVID-19 vaccination studies. Those cases were mostly asymptomatic or mild, and so far Oregon cases fall into one of these two categories.
State epidemiologist Dr. Dean Sidelinger said that’s good news considering the COVID-19 death toll for unvaccinated 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 security measures, such as wearing masks and social distancing, even after receiving the vaccine. Until enough vaccinations are administered to achieve herd immunity – something that is months away – breakthrough cases will continue to occur.