Dean Sidelinger, the Oregon Health Authority’s state health officer, said at a Feb. 12 briefing that there were two cases each in Yamhill and Lane counties.
“We’re beginning to receive reports of individuals who have tested positive after receiving a COVID-19 vaccine,” Sidelinger said, according to a series of tweets by the Oregon Health Authority. “These are called ‘breakthrough cases.’ These are people who get sick with COVID-19 at least 14 days after completing their vaccination series.”
With vaccine efficacy at around 95 percent, breakthrough cases are to be expected in some 5 percent of vaccine recipients.
“Clinical trials of both vaccines presently in use included breakthrough cases,” Sidelinger said, according to the agency. “In those cases, even though the participants got COVID, the vaccines reduced the severity of illness.”
He said in all four breakthrough cases, people either showed mild symptoms or were entirely asymptomatic. Sidelinger added that he expects to see more breakthrough cases and that “getting as many Oregonians as possible vaccinated remains a critical objective to ending the pandemic.” More than 17,000 Oregonians are being vaccinated each day, on average.
Sidelinger also said that cases have been confirmed in Oregon of the COVID-19 variant first detected in the United Kingdom, dubbed B.1.1.7.
“We have already discovered that the more easily transmitted virus variant from the UK is present here in Oregon. Other variants may follow,” Sidelinger said.
The Centers for Disease Control and Prevention (CDC) stated on Feb. 14 that there have been 1,173 confirmed cases of B.1.1.7 in 40 states. Two other variants, one first identified in South Africa (B.1.351) and the other in Brazil (P.1), have also led to infections in a handful of states.
As of Feb. 15, a total of 17 cases of the South African strain have been confirmed in California, Illinois, North Carolina, South Carolina, Texas, and Virginia. Just three cases of the Brazil variant have been confirmed so far, in Minnesota and Oklahoma.
Meanwhile, scientific advisers to the British government believe the UK variant is likely deadlier than previous strains.
In a study released Feb. 12 (pdf), scientists stated that B.1.1.7 “is associated with an increased risk of hospitalization and death compared to infection” with the original strain of the CCP (Chinese Communist Party) virus, commonly known as the novel coronavirus.
The UK variant, which was earlier determined to be around 30 to 70 percent more transmissible than other strains, has been spreading relatively quickly across the country.
CDC director, Dr. Rochelle Walensky, told CBS’ “Face the Nation” on Feb. 14 that the UK variant may soon become the “dominant strain” in the United States.
“We know now that, or we estimate now that about 4 percent of disease in this country is related to B.1.1.7,” she said. “And we have projections that it may be the dominant strain by the end of March.”
In light of the new variants spreading in the United States, the CDC stated that “rigorous and increased compliance with public health mitigation strategies, such as vaccination, physical distancing, use of masks, hand hygiene, and isolation and quarantine, is essential to limit the spread of the virus that causes COVID-19 and protect public health.”
Some states, such as Iowa and Montana, have lifted some restrictions, including masking requirements, which Walensky said is a mistake.
“I think we’re not out of the woods yet. We need to get our kids back to school. We need to get our communities back to some normal functioning before we can start thinking about letting up our mitigation strategies,” she told CBS.