Ken Jarecki remembers it was a Monday when he started feeling crappy. This was back in September, when breakthrough COVID cases weren’t that common, especially in Vermont.
Jarecki is from Pittsfield. He’s vaccinated — he got two shots back in March — and he’s careful about COVID. He always wears a mask at work or going to the post office.
The week before he got sick, he went to a birthday party at a restaurant with a group of friends. Everyone was vaccinated.
“At the end of dinner, there was a couple sitting at the other side that I had never met,” he said. “I had a face-to-face conversation with one of them. And I never thought anything. I went home.”
The couple ended up testing positive for COVID. Jarecki did too. He had flu symptoms for over a week, and fatigue that lasted a lot longer. It was two months before he started feeling like himself.
Now, he’s recovered. But getting sick came as a big surprise.
For many public health experts though, what happened to Jarecki, and thousands of Vermonters who’ve had breakthrough COVID cases since, was predictable.
One reason is the time of year.
“The weather turns colder, we go back indoors,” said Mark Cameron, an immunologist and infectious disease researcher at Case Western Reserve University in Ohio.
“The flu, colds, normal respiratory illnesses, start to rise now and accumulate through the holiday season all the way to spring,” he explained. “COVID-19 is taking advantage of this as well.”
If you think back to this time last year, nearly everyone was wearing masks and not socializing much. That’s no longer the case.
There’s also the delta variant, which is still causing the vast majority of infections in the U.S.
“It's just simply better at getting inside our cells,” Cameron said.
Waning immunity, explained
This year there’s also vaccines against COVID. For many Vermonters though, it’s been more than six months since their last shot. This matters when we think about the risk of infection.
“We know that the vaccine protection declines over time,” said Stephen Kissler, a researcher who studies the spread of infectious diseases at Harvard’s School of Public Health.
“While the vaccines still seem to be pretty good at preventing people from going to the hospital and dying, we are still seeing people with breakthrough infections that are symptomatic,” he said. “That is not what we want to see.”
This might help explain what happened to Jarecki.
The dinner at that restaurant was about six months after he got the vaccine. Around this time there’s a change in your immune system that means some virus bits might be able to sneak into your body, even if you’re vaccinated.
"The science clearly tells us everyone who received a vaccine five, six months ago needs to go and get a boost."Ali Mokdad, epidemiologist at the University of Washington
It’s a little deep in the immunological weeds, but the reason has to do with your first line of defense against COVID — neutralizing antibodies.
“This virus can get by that first line of defense, once we’re six or eight months away from the vaccine,” said Cameron, from Case Western Reserve University. “That is the big deal about the virus that causes COVID-19.”
That initial defense can still help reduce the overall amount of virus inside you, Cameron said. And meanwhile, your immune system has other protections in place — reserves called memory cells — that last a lot longer. They can help prevent you from getting really sick.
“That's why vaccinated individuals have less risk of hospitalization and death if they do become infected,” Cameron said. “Even if the virus gains entry into our cells, the vaccinated individuals already have a memory response to fight the virus before it truly injures our lungs.”
So it could be that for Jarecki, his body’s first line of defense wasn’t robust enough to stave off infection completely. But other safeguards — those memory cells he had from the vaccine — might have stepped in to stamp out the virus before he was sick enough to go to the hospital.
How Vermont is unique
There’s another factor at play that could help explain why Vermont, in particular, has seen such high case counts in recent weeks: Only a small proportion of residents have had a COVID infection. That’s not the case across the country.
Researchers at the Institute for Health Metrics and Evaluation at the University of Washington estimate that 13% of Vermonters have been infected with COVID. Whereas in a place like Florida, more than 40% of the population has had COVID, according to their models.
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“Florida allowed the virus to spread and infect everybody that it could infect,” said Ali Mokdad, an epidemiologist at the University of Washington and part of the team that models statewide rates of COVID infections.
“This is not a success story what happened in Florida — this is a failure,” he said. “They lost a lot of people, they overwhelmed their hospitals.”
That hasn’t happened in Vermont. So most people have protection against COVID from the vaccine, rather than an infection. And for many, that protection is waning.
That’s why the CDC says every adult should get a booster shot.
“The science clearly tells us everyone who received a vaccine five, six months ago needs to go and get a boost,” Mokdad emphasized.
Jarecki and his wife got their boosters in early November. They're still being careful.
“We’re still wearing masks now. Because with these high numbers, I don’t really trust anything,” Jarecki said.
The newest variant of concern
With the new omicron variant looming, some public health experts say there’s a chance we might have to act more cautiously going forward, like avoiding travel and large gatherings. That’s if the strain proves extremely transmissible or masterful at evading our immune response.
“I think that's a low-probability outcome, given what I've seen so far,” Kissler, from Harvard, said by email. It will be several weeks before there are enough data to draw any conclusions, he added.
Meanwhile, the familiar advice still stands.
“Vaccinate, mask, boost and persevere," Cameron summarized. Others recommended keeping an eye on case numbers in your community to help determine personal risk level.
"We have to get used to this virus impacting us when we let our guard down," Cameron said. “The ill effects of this virus can happen anywhere, and they will.”
Lexi Krupp is a corps member for Report for America, a nonprofit national service program that places journalists in local newsrooms to report on under-covered issues and regions.
Have questions, comments or tips? Send us a message or get in touch with reporter Lexi Krupp @KruppLexi.
