Two Doses of COVID Vaccine May Increase Risk of Long COVID Symptoms


Patients who received two doses of a COVID-19 vaccine were more likely to experience symptoms of long COVID compared with people who were unvaccinated or had received one dose, a peer-reviewed study showed.

Two Doses of COVID Vaccine May Increase Risk of Long COVID Symptoms

People who received two doses of a COVID-19 vaccine may be more likely to get long COVID symptoms compared with those who received one or no dose, a peer-reviewed study showed.

The study authors — who published their report on Dec. 20, 2022, in PLoS One — looked at what factors predicted whether or not 487 adults who had a COVID-19 infection later developed long COVID symptoms.

They also looked at what symptoms those with long COVID reported experiencing.

The authors found five statistically significant predictors of developing long COVID: pre-existing medical conditions, having a higher number of symptoms during the acute phase of COVID-19, two doses of COVID-19 vaccination, the severity of illness, and admission to a hospital.

In other words, these five factors were “independently associated” with a heightened risk of long COVID, Dr. Peter McCullough noted in a Substack post about the study.

Long COVID symptoms experienced by the study participants included fatigue, cough, difficulty breathing, chest pain, loss of taste or smell, brain fog, heart palpitations and anxiety.

When it came to discussing the link between two doses of COVID-19 vaccination and the development of long COVID symptoms, the study authors called it an “observational paradox” and cited research that contradicted what their data showed.

Dr. Pierre Kory told The Defender he wasn’t surprised the researchers found a link between two vaccine doses and long COVID — and he also wasn’t surprised the authors downplayed the finding.

Kory is president and chief medical officer of the Front Line COVID-19 Critical Care Alliance. He also co-leads a specialized clinic for treating COVID-19, long COVID and vaccine injury syndromes.

“It’s not scientific to say it’s an ‘observational paradox,’” Kory said. “If they [the authors] want to conclude … there’s a proven consensus truth that vaccination lowers the risk of long COVID, then yes, that is a paradox.”

Kory said the authors tried to make that argument — but did a weak job. “If there’s any finding which puts the vaccines in a bad light, [authors seeking to publish their work] immediately have to try and present it in a way that supports vaccination.”

Dr. Madhava Setty agreed, noting it was plausible the authors felt they had to “cast doubt on such findings” to see their work in print.

Or perhaps, based on the studies they cited, the study authors believed an increased risk of developing long COVID symptoms due to COVID-19 vaccination wasn’t possible, Setty said.

But researchers “should not throw away evidence based on forgone conclusions,” Setty said. “That’s called dogma … One would think that scientists would be interested in a revelatory finding and not be dismissive about their own data.”

The Defender reached out to the study’s corresponding author for comment, but he did not respond by our publication deadline.

Medscape reports deaths from long COVID, ignores vaccine link

As news of the study’s findings spread, Medscape — a privately held company that reports medical news — on Jan. 3 reported “new CDC [Centers for Disease Control and Prevention] data” showing “thousands of US deaths” from long COVID.

Medscape’s article — which was “vague” and “weak,” said Kory — squarely placed the blame on COVID-19 infections and ignored evidence that vaccination is a risk factor.

Kory said he suspected the Medscape article was intended as a “distraction” from the fact that COVID-19 vaccines are increasingly linked to poor health outcomes, including death. He said:

“This is a war of information. So it’s not a shock that two weeks later, an article appears in Medscape that tries to introduce the idea that people are dying from COVID long after they had COVID.”

The CDC in 2023 updated its guidance for reporting COVID-19 and long COVID on death certificates — but still fails to investigate the soaring numbers of unexpected or “excess” deaths seen since the vaccine mandates, Kory said, adding:

“There are things they [CDC officials] could do if they honestly want to approach this from a scientific perspective with a true desire to try to understand what’s going on. You would do a little bit more than just trying to put COVID on death certificates.”

How COVID vaccines may lead to long COVID

The CDC broadly defines long COVID as “signs, symptoms, and conditions that continue or develop after acute COVID-19 infection.”

There are at least two ways COVID-19 vaccines may lead to increased risk of long COVID, experts told The Defender.

First, antibody-dependent enhancement (ADE) is a known side effect of COVID-19 vaccination that can lead to more severe illness, according to Setty.

ADE means “raising antibodies that don’t protect, but actually make a viral infection even worse,” Science reported.

“The study unequivocally shows that long COVID risk is correlated with severity of disease,” Setty said. “This known mechanism would therefore explain the higher risk of long COVID in vaccinated people. Their [the study authors’] observation is not as ‘paradoxical’ as they report.”

Kory raised the same point:

“I think the vaccinated do worse. You can’t tell that from U.S. data because the U.S. data is corrupted … but when you look at other countries, Scotland, the U.K., Australia, you see pretty consistently that the vaccinated were disproportionately inside hospitals.”

According to McCullough, “In my practice, the most severe cases of long-COVID are in vaccinated patients who also had severe and or multiple episodes of SARS-CoV-2 infection.”

The study authors said they did not find a statistically significant interaction between illness severity and vaccination — but that doesn’t necessarily mean that there isn’t one, Kory said. “That’s kind of a messy rabbit hole to go down.”

The second way COVID-19 vaccines might increase a person’s risk of long COVID is by flooding the body with additional spike protein which, in turn, could lead to persistent symptoms, Kory said.

McCullough voiced this theory, too, noting on Substack that mRNA COVID-19 vaccines produce “a massive additional load of full-length Spike protein … known to circulate in the blood for 6 months or more.”

Conflating long COVID with ‘long vax’

The scientific literature on what causes long COVID is “messy,” Kory said, because researchers — including the study’s authors — sometimes conflate long COVID with what’s called “long vax.”

Long vax syndrome refers to long-term symptoms after COVID-19 vaccination and is a different condition from long COVID, although they may share common symptoms.

Since the medical establishment has generally run with the narrative that COVID-19 vaccines are safe and effective, there are very few studies on long vax, Kory said, but the condition is very common.

“Many vaccine-injured have long vax,” he said, adding that in his practice he sees roughly two cases of long vax for every case of long COVID. He explained:

“The only way to differentiate that is by [medical] history … patients will tell you, I got vaccinated on a Monday and then the next 10 days this happened, this happened and they’re able to attribute everything to the vaccine.

“Others, they attribute their symptoms to a COVID-19 infection.”

If researchers do not clearly distinguish between the two, studies ostensibly on long COVID likely include people who, in fact, experienced long vax.

“So you have a really perverted and distorted literature,” Kory said.