State officials collect data on ‘breakthrough’ infections — where COVID develops after vaccination.
When UConn women’s basketball coach Geno Auriemma was diagnosed with COVID-19, it was four days after he had received his second vaccine dose.
“If I hadn’t gotten the vaccine ... I might be really, really, really sick,” Auriemma said in March.
Cases like Auriemma’s, called “breakthrough” infections, ”do happen, just as they happen with any other vaccine,” said Department of Public Health spokeswoman Maura Fitzgerald.
But exactly how many there are in Connecticut is difficult to tell.
“Reports of possible breakthrough infections are being collected as part of a special epidemiologic project,” said Fitzgerald. “The Department of Public Health will publish a summary report when case investigations have been completed and the data are analyzed.”
It could, theoretically, be thousands of cases, though ultimately a small percentage of the total number of vaccinated people.
“Remember, the vaccine is not 100 percent effective, Moderna and Pfizer are only 95 percent effective,” Tom Balcezak, chief medical officer at the Yale New Haven health system, said during a press conference. “So, that means that five out of every 100 people that are exposed to the virus in a high risk exposure may become infected.”
So far, Balcezak said Yale has seen “just a small handful of breakthrough infections.” “We've had six across the Yale New Haven health system admitted to the hospital,” he said. “It's a really small number, all of them have done well and been discharged home.”
Ajay Kumar, executive vice president and chief clinical officer at Hartford Healthcare, said on March 26 that he had not seen any breakthrough infections.
“So far we have no patients who have been vaccinated or partially vaccinated admitted to Hartford Healthcare because of COVID,” he said. “Unrelated reasons, maybe, but not because of COVID.”
Asha Shah, associate director of infectious diseases at Stamford Health said only that “the majority of our inpatient COVID cases are in individuals who have no record of vaccination or who have been incompletely vaccinated (first dose a few days prior to admission).”
George Kuchel, director of the UConn Center on Aging, said he hasn’t seen any cases yet.
“I haven't myself, but I've certainly heard about it, so there are cases,” he said. “It's not particularly common, but I think it's a cause for concern.”
Of particular concern to both Kuchel and Yale’s Balcezak is how the vaccines will work against new variants of the virus.
“We expect some people who are vaccinated to be infected,” Balcezak said. “It's not a panacea.”
Balcezak said all six of the breakthrough cases in the Yale health system were found to be the more infectious B.1.1.7 strain, originally sequenced in the United Kingdom. But because it is so widespread in Connecticut, it may be just the “law of numbers.”
“Because it is becoming the dominant variant, it is so much more transmissible, I don't think it tells you anything about immunity conveyed by the vaccine and exposure to [the variant] B.1.1.7,” he said.
Kuchel, as director of UConn’s Center on Aging, is particularly concerned about older patients.
He said vaccines work in two ways: Sterilizing immunity, which Kuchel defined as “the ability to fend off the infection in the first place,” versus “the ability to clear the infection once it takes place.”
“With aging, it's actually the latter that's often the problem,” he said. “It's still not entirely clear that frail, older adults and people who are most vulnerable to COVID are as protected with these different vaccines, as their younger counterparts and their healthier counterparts. That jury's still out.”
By some definitions, Auriemma’s case would not be considered a “breakthrough” infection.
“That should be two weeks beyond their second dose,” Balcezak said. “So we're calling those ‘breakthrough COVID.’”
After Auriemma tested positive for COVID, experts speculated that his case was asymptomatic because he had been vaccinated. There is some evidence to support that argument.
A study published on March 29 in the journal Nature Medicine showed that the “viral load was substantially reduced for infections occurring 12 to 37 days after the first dose of vaccine,” suggesting that breakthrough infections are very unlikely to cause a severe reaction.
“These reduced viral loads hint at a potentially lower infectiousness, further contributing to vaccine effect on virus spread,” the study says.
That’s been true as well for breakthrough cases in Connecticut.
“They've all done fine,” Balcezak said of COVID cases in vaccinated patients. “It's rare to have severe illness, meaning an illness that needs you to be admitted. And even if you do have an illness that needs you to be admitted, the course of that illness in general is much, much better.”