Myocarditis and COVID-19 Vaccines: How the CDC Missed a Safety Signal and Hid a Warning

A signal appeared in February 2021, but the CDC did not warn the public until months later.

Illustration by The Epoch Times, Getty Images, Shutterstock

COVID-19 vaccines cause heart inflammation, U.S. authorities now acknowledge. But after being warned in early 2021 about a “large number” of cases among healthy, young people in Israel after COVID-19 vaccination, authorities did not immediately alert the public while also failing to detect a safety signal that was present in the United States, an Epoch Times investigation has found.

Even after deaths from myocarditis—inflammation of the heart—were reported and myocarditis was designated as a likely side effect of the shots, U.S. officials kept recommending vaccination for virtually the entire populace.

That led to millions of young people receiving a vaccine.

Many of those people suffered.

Aiden Ekanayake, 14, was one of them. He received a dose of the Pfizer-BioNTech vaccine in May 2021, and a second dose in June 2021.

Two days after the second dose, Aiden was woken in the middle of the night with pain that was comparable to when he tore his anterior cruciate ligament. His mother, Emily, rushed him to the hospital, where he spent days receiving care. Even after he was discharged, his exercise was limited for more than four months.

Ms. Ekanayake trusted the U.S. Centers for Disease Control and Prevention (CDC) before the experience. Now, she does not.

“I hate them. I think they’re evil,” Ms. Ekanayake told The Epoch Times.

No Transparency

The CDC, America’s public health agency, was warned by Israel on Feb. 28, 2021, about a “large number” of myocarditis cases after Pfizer COVID-19 vaccination, documents obtained by The Epoch Times show.

Internally, the warning was designated as “high” importance and set off a review of U.S. data. The review found 27 reported cases in the United States, according to a U.S. government memorandum dated March 9, 2021. The incidence rate was low, but “missing and incomplete data make it challenging to assess causation,” the memo stated. The U.S. Food and Drug Administration (FDA), it said, “has not made a final determination regarding the causality.”

People receive a dose of the COVID-19 vaccine at Tel Aviv Sourasky Medical Center in Tel Aviv, Israel, on Dec. 20, 2020. Amir Levy/Getty Images

Weeks later, neither the CDC nor the FDA had alerted the public to the issue, even after the death of a previously healthy 22-year-old Israeli woman and briefings from Israeli officials and U.S. Department of Defense (DOD) researchers.

Like Israel, the DOD was recording a higher-than-expected number of myocarditis cases. Patients were mostly young, healthy males.

The CDC met with military officials twice behind closed doors in April 2021. Military officials presented data during at least one of the meetings to the CDC. That presentation, which has never been released to the public, “included our preliminary patient data and analysis that suggested to us that myocarditis was indeed a possible side effect to the messenger RNA COVID-19 vaccines (within the US military),” Dr. Jay Montgomery, one of the presenters, told The Epoch Times via email.

The Pfizer and Moderna vaccines use messenger RNA (mRNA).

On April 27, 2021, after the meetings, then-CDC Director Dr. Rochelle Walensky finally spoke about the matter in public, during a White House briefing.

Dr. Walensky said “we have not seen any reports” of myocarditis after vaccination. That’s false, according to CDC data—the agency received 141 reports of myocarditis in the Vaccine Adverse Event Reporting System (VAERS) by the end of March 2021. Another 24 cases were recorded in the Vaccine Safety Datalink, a second system run by the CDC.

Additionally, before the briefing, Dr. Walensky was copied on multiple threads discussing myocarditis and a related condition, pericarditis, including a thread about doctors in California seeing the cases, internal emails obtained by The Epoch Times show. She responded to one of the threads, saying the information was “super helpful.”

“We have not seen a [safety] signal,” Dr. Walensky also told reporters during the briefing, “and we’ve actually looked intentionally for the signal in the over 200 million doses we’ve given.”

Aiden Ekanayake in a hospital in June 2021. Courtesy of Emily Ekanayake

Signal Found

The FDA authorized the Moderna and Pfizer vaccines in late 2020.

The CDC and FDA are supposed to monitor data from VAERS, which officials have described as the country’s “early warning system” for possible vaccine problems. But they failed to detect a safety signal for myocarditis after COVID-19 vaccination that triggered on Feb. 18, 2021, when using a statistical analysis method called Proportional Reporting Ratio (PRR), according to archived VAERS data from the National Vaccine Information Center, The Epoch Times confirmed.

The CDC initially said it started running PRRs in February 2021, but later acknowledged that was false. The agency now says it did not start PRRs until 2022. The first time the CDC ran complete PRRs, officials detected a signal for myocarditis, according to files obtained by The Epoch Times.

“It’s unimaginable that they wouldn’t have seen the signal,” Brian Hooker, senior director of science and research at Children’s Health Defense, who detected an early signal for myocarditis in VAERS using a different method, told The Epoch Times. “They were alerted by the DOD. They were alerted by the Israeli Ministry of Health. And so, if they just didn’t know then, they have absolutely no excuse because they were warned.”

Children’s Health Defense, a nonprofit that says its mission is to end childhood health epidemics, first obtained the emails between Israel and the CDC.

Dr. Walensky, who has since departed the CDC, has not responded to a request for comment about her myocarditis claims.

A CDC spokesperson told The Epoch Times via email: “CDC has been continuously monitoring the safety of COVID-19 vaccines since they began to be administered in the United States. At the time of the director’s press conference, CDC did not have sufficient evidence to conclude there was a safety signal for myocarditis following mRNA COVID-19 vaccination.”

The CDC has said it did not run PRRs in 2021 because officials were relying on a different analytic method, called Empirical Bayesian data mining. It’s unclear when that method, utilized by the FDA, first detected a signal for myocarditis. The FDA has declined to answer questions on the matter. The CDC has told The Epoch Times that its 2022 detection of a signal for myocarditis using PRRs was “consistent with” the data mining results.

(Left) The U.S. Food and Drug Administration (FDA) in White Oak, Md., on June 5, 2023. (Right) Centers for Disease Control and Prevention Director Rochelle Walensky testifies before the Senate Health, Education, Labor, and Pensions Committee about the response to the COVID-19 pandemic on Capitol Hill in Washington on Nov. 4, 2021. Madalina Vasiliu/The Epoch Times, Chip Somodevilla/Getty Images

Both the CDC and FDA use contractors to process VAERS data.

“Even FDA doesn’t really know the mechanics of how its contractor does the data mining,” one CDC official said in an email obtained by The Epoch Times. The official and the FDA did not respond to requests for comment on the email.

A safety signal is a sign that an adverse event may be caused by a vaccine. Authorities say signals can only be substantiated with further research.

“Once the safety signal comes up, why not start warning the public about the fact that ‘hey, you can take it if you want, but understand that there is this risk that we have discovered and we are looking into it,’” Dr. Anish Koka, an American cardiologist, told The Epoch Times.

One possible motivation for not fully examining the issue was that it could have led to a halt in vaccination. The CDC and FDA essentially imposed a pause on Johnson & Johnson’s shot on April 13, 2021, after a small number of blood clotting cases.

“A pause of the Pfizer/Moderna administration (much like the J&J blood clot pause) will have an adverse impact on US/CA vaccination rates,” one military official said in a message obtained by The Epoch Times that was flagged for top CDC officials.

Between February 2021 and May 2021, the percentage of the U.S. population that had received a COVID-19 vaccine soared from 14.2 percent to 50.5 percent.

“It was most likely a strategic move in order to make sure that they didn’t curtail vaccination rates,” Mr. Hooker said.

Backlog

A day after Dr. Walensky’s unambiguous statement, CDC officials privately acknowledged the difficulty in processing VAERS reports because so many had been lodged.

“Due to the large number of reports that we are receiving at this time, processing is taking longer than usual,” one official said. The message was sent to a woman who said she'd filed a VAERS report for her son’s myocarditis on April 21 but that the report had still not appeared in the system days later.

Elaine Miller, a CDC official, wrote around the same time that there were “processing delays” for VAERS reports.

A medical assistant holds a tray of syringes filled with doses of Moderna COVID-19 vaccine at a vaccination site in Los Angeles on Feb. 16, 2021. Apu Gomes/AFP via Getty Images

One of the contractors used by the CDC estimated before the vaccines were rolled out that no more than 1,000 reports would be filed per day. The number soared above that estimate by the end of 2020, internal documents obtained by The Epoch Times show.

Workers for the contractor, General Dynamics Information Technology, increased the speed at which they processed but were “unable to keep up with the increased surge in reports at current staffing levels,” the contractor informed the CDC in one message.

The backlog increased to nearly 94,000 reports even after the contractor hired nearly 300 additional staff members.

Dr. Adam Hirschfeld, 36, of Ohio, submitted a report to VAERS soon after suffering myocarditis following COVID-19 vaccination in January 2021. It took months for the CDC to respond to him. “I could have been dead by then,” Dr. Hirschfeld told The Epoch Times.

Health care providers who administer COVID-19 vaccines are required to report serious adverse events, including all cases of myocarditis, to VAERS.

But not all doctors were following the rules, other emails show.

“Providers aren’t reporting these cases to VAERS,” Dr. John Su, one of the CDC’s top vaccine safety officials, wrote to colleagues on May 17, 2021. He also wrote that the “myocarditis thing” was “exploding.”

CDC officials, in correspondence with officials in Washington state, said around the same time that nine post-vaccination myocarditis cases had not been reported to VAERS.

The backlog was eventually cleared. VAERS data show that 146 cases of myocarditis or pericarditis were reported by the end of March 2021. An additional 158 cases were reported in April 2021 and 487 more were entered in May 2021.

Just a third of the cases reported to VAERS through April 26, 2021, were fully processed as of May 3, 2021, according to an internal presentation.

In addition to Dr. Walensky’s false claim, the CDC has falsely told other health officials and media outlets that it did not receive any reports until May or June 2021, internal emails show.

The Emergency Operations Center at the Centers for Disease Control and Prevention in Atlanta on March 19, 2021. Eric Baradat/AFP via Getty Images

Another CDC vaccine safety monitoring system, V-safe, did not include myocarditis despite the CDC and FDA identifying the heart inflammation as an adverse event of special interest, or a possible side effect, for the COVID-19 vaccines before they were authorized. The Vaccine Safety Datalink did include myocarditis but did not detect a signal until 2022, possibly because it was using a too-narrow case definition. A fourth system, run by the FDA and partners like CVS, detected a signal in 2023.

Cases Started in January

Doctors started seeing postvaccination myocarditis cases in January 2021, months before the public was informed about them.

The U.S. military researchers, for instance, detailed in a paper that 22 previously healthy service members suffered from myocarditis after vaccination as early as January 2021.

Seventeen cases happened in January 2021 alone in Israel, Israeli researchers reported in another study.

Dr. Dror Mevorach, a co-author of the paper, said he tried warning Pfizer of the possible link between myocarditis and its shot.

“They refused to believe me for a period of four months,” Dr. Mevorach told Haaretz. Pfizer did not respond to a request for comment.

Members of the The United States Marine Corps wait in line to receive the Moderna COVID-19 vaccine at Camp Hansen in Kin, Japan, on April 28, 2021. Carl Court/Getty Images

For many cases, doctors ruled out other possible causes, such as COVID-19—strengthening support for the theory that the vaccines were the cause.

Case reports were frequently published months after cases actually happened, despite being submitted to journals as early as Feb. 16, 2021, data from the journals show. Some journals refused to publish other papers. Dr. Dimitri Christakis, editor-in-chief of JAMA Pediatrics, told CDC officials that he had “rejected” a case series while saying he'd “welcome” one from the agency, emails obtained by The Epoch Times show.

JAMA Pediatrics did not publish any studies about myocarditis after COVID-19 vaccination until Feb. 25, 2022. A query to Dr. Christakis returned an away message.

The number of cases reported in journals increased as 2021 went on, following the pattern of VAERS reports.

The first cases were reported in the literature in March 2021. Just 16 more were published by the end of June 2021. The number spiked to 290 in July 2021.

The Israeli group’s report was not released until October 2021, more than six months after the first case was detected.

“It takes time to process the data and collect it and report on it. Of course, when you write an article, there is also a review and a revision process, and it took several months until we were able to publish it online,” Dr. Rabea Asleh, director of the heart failure unit and the cardiovascular research center at the Hadassah University Medical Center and a co-author of the paper, told The Epoch Times.

He added later, “There were early reports after the vaccine of myocarditis, we were just waiting to provide more comprehensive information.”

‘Seems Reasonable’

A case report from Spanish researchers was the first in the world to be published in the literature. Dr. Javier Bautista Garcia and colleagues reported a 39-year-old doctor who was hospitalized for six days following his first dose of a Pfizer vaccine.

The doctor tested negative for COVID-19, and researchers excluded other possible triggers.

“Given the evident temporal relationship and the serological pattern compatible with immunization after the vaccine, having ruled out an acute infection, it seems reasonable to associate the clinical picture developed by this patient with an adverse reaction to the BNT162b2 vaccine against COVID-19,” the researchers wrote. BNT162b2 is the name for Pfizer’s shot.

Italian researchers soon after described a previously healthy 56-year-old man who developed myocarditis after a second dose of the Pfizer vaccine.

“Even if no causal relationship can be demonstrated in this case report between the second dose of BNT162b2 mRNA COVID-19 vaccination and acute myocarditis, the timing of the onset and the inflammatory nature of the event make the relationship plausible,” they said.

Researchers in Israel and the United States also reported cases in the spring.

The explosion of reports in June 2021 included a case series of American children as young as 14 suffering from myocarditis shortly after receiving shots and requiring hospitalization. U.S. researchers also reported four cases in Pennsylvania, one case in New Jersey, six cases in Massachusetts, four cases in Minnesota, seven cases in Texas and Virginia, another case in Texas, one case in California, two cases in Missouri, one case in New York, two cases in Hawaii, and seven cases in North Carolina.

“The striking clinical similarities in the presentations of these patients, their recent vaccination with an mRNA-based COVID-19 vaccine, and the lack of any alternative etiologies for acute myocarditis suggest an association with immunization,” CDC officials said in a June 29, 2021, editorial on some of the cases.

French experts said in a separate paper, after analyzing 214 reports of myocarditis following COVID-19 vaccination, that their data “suggests that, similar to other vaccines, mRNA COVID-19 vaccines are associated with myocarditis.”

First Acknowledgement

Israeli media reported in April 2021 a second post-vaccination myocarditis death, a 35-year-old previously healthy young man. Officials there, meanwhile, revealed that an investigation determined 55 myocarditis cases were in relation to vaccination and 81 more were probably related.

In the first calculation of the rate of harm, on May 31, 2021, experts assigned by the Israeli Ministry of Health estimated one case of myocarditis per 6,637 second Pfizer doses among males 16–19 and one case per 9,208 second Pfizer doses among males 20 to 24.

“We found a high and statistically significant risk of myocarditis ... and in our opinion the relationship found can fulfill the criteria for a causal relationship,” the experts said. The ministry said: “The conclusion is that there is a high probability of a connection between the administration of the second Pfizer vaccine and the increased risk of myocarditis, especially in young boys.”

The CDC also formed a new team, drawing from across the agency, in May 2021. It focused on digging into reports of myocarditis in the United States. And the agency held calls for health care providers, including doctors from pediatric hospitals, to craft guidance and give advice. But it shielded much of the work from public view, including not discussing myocarditis at all during open meetings with vaccine advisers on May 5, 2021, and May 14, 2021.

Between those meetings, the FDA expanded access to Pfizer’s vaccine to those aged 12 to 15 based on data from a trial in which 1,131 adolescents received the vaccine and none died or experienced myocarditis. Dr. Walensky recommended the age group receive the vaccine. Neither the FDA nor Dr. Walensky mentioned myocarditis.

A child receives a dose of the Pfizer BioNTech COVID-19 vaccine at the Fairfax County Government Center in Annandale, Va., on Nov. 4, 2021. Chip Somodevilla/Getty Images

Ms. Ekanayake, Aiden’s mother, had read the Israeli research. But she and her son decided he should get vaccinated because they believed the benefits outweighed the risks, in part because of Dr. Walensky’s public statement.

“She said at some point that there wasn’t a link, so we proceeded,” Ms. Ekanayake told The Epoch Times. “So when my son was vaccinated, there was absolutely no informed consent.”

Aiden received his first shot on May 10, 2021.

Kyle Warner, a professional mountain bike racer who lives in the Western U.S. and suffered myocarditis after being vaccinated in May and June 2021, said the lack of warning from U.S. officials about the possible adverse event also led to him receiving a vaccine.

“A lot of us were under the false assumption that ‘well, it sounds like no one’s been hurt so far, there hasn’t really been any issues going on that I’ve heard of, so it seems to be safe and effective, like they’re saying,’” Mr. Warner said. “It kind of perpetuated this myth of ’safe and effective, period.'”

If a warning was issued, “it would have saved me,” he added.

On May 24, 2021, a CDC work group acknowledged for the first time that reported post-vaccination myocarditis cases were higher than expected in people aged 16 to 24. But the group did not warn young people not to get vaccinated. Instead, it said doctors should be prepared to recognize the heart inflammation and manage the cases appropriately.

The CDC, after the acknowledgment, kept recommending vaccination while alleging COVID-19 posed more of a risk than myocarditis. Dr. Walensky said that most cases had “fully resolved” with rest and treatment and that “getting vaccinated is our way out of this pandemic.”

With that message, the “tone [was] set,” Jason McDonald, Dr. Walensky’s press secretary, said in an email to her obtained by The Epoch Times. “Yes, I was pleased,” Dr. Walensky responded.

Risk-Benefit Analyses

COVID-19 poses little risk to young, healthy people. That means there’s a higher bar of effectiveness and safety vaccines must pass for vaccination to make sense, experts say.

“You’ve really got to show the benefits markedly outweigh any risks,” Dr. Peter Collignon, an infectious diseases physician at Canberra Hospital in Australia, told The Epoch Times previously.

U.S. officials and other vaccine proponents initially referred to myocarditis after vaccination as rare and mostly or even completely mild, citing early literature. “The facts are clear: this is an extremely rare side effect, and only an exceedingly small number of people will experience it after vaccination,” the American Academy of Pediatrics, the CDC, and other entities said in a joint statement on June 23, 2021. “Importantly, for the young people who do, most cases are mild, and individuals recover often on their own or with minimal treatment.”

The original clinical trials included a scant number (Pfizer) or no (Moderna) children. One person died in Pfizer’s trial from cardiac arrest, but their age was not made public, while another, 36, suffered pericarditis. Some FDA advisers initially recommended waiting to vaccinate 16- and 17-year-olds, but were shot down by U.S. officials.

(Left) Empty COVID-19 vaccine vials at a vaccination center in Rosenheim, Germany, on April 20, 2021. (Right) A nurse prepares a dose of the Pfizer COVID-19 vaccine at a vaccination site in Los Angeles on March 10, 2021. Christof Stache/AFP via Getty Images, Frederic J. Brown/AFP via Getty Images

The CDC’s first formal comparison of the benefits and risks of the COVID-19 vaccines was presented during a meeting on June 23, 2021. It estimated that one million second Pfizer doses would cause 56 to 69 cases of myocarditis in males aged 12 to 17, and 45 to 56 cases of myocarditis in males aged 18 to 24.

No other suspected or confirmed side effects, such as severe allergic shock, were included as a risk.

The same number of doses would prevent thousands of COVID-19 cases, hundreds of hospitalizations, and a handful of deaths over 120 days, the agency estimated.

“The direct benefit-risk assessment shows positive balance for all age and sex groups,” Megan Wallace, a CDC official, told the meeting.

The model assumed sky-high effectiveness, based largely on trial data. The calculations were based largely on a study summarizing Pfizer’s trial results, a CDC spokesperson told The Epoch Times in an email.

The foundations of the assessment were questioned by some researchers, who said that if just one assumption in the model were changed, the calculus shifted to risks outweighing benefits.

The “second dose vaccination is unfavorable at young ages,”  the researchers said, when incorporating how VAERS underestimates risk.

Another group of researchers soon published a paper that found healthy males aged 12 to 17 faced a higher risk of hospitalization from myocarditis and other cardiac issues after vaccination than after COVID-19. The paper was released as a preprint but later published in a journal.

A teenager receives a dose of the Pfizer-BioNtech COVID-19 vaccine at Clalit Health Services in Tel Aviv, Israel, on Jan. 23, 2021. Jack Guez/AFP via Getty Images

The researchers improved on the CDC’s model by subtracting incidental hospitalizations and stratifying by underlying conditions, making it possible to make one set of calculations for healthy young people and another for those with poor health.

The researchers said officials should study the issue more closely and consider following the example of other countries such as Sweden that were holding off on recommending the vaccination of healthy children.

Dr. Tracy Beth Hoeg, one of the researchers, told The Epoch Times that she thought U.S. authorities would make changes due to the research. The main options: pause the vaccinations in children, lower the recommended number of doses from two to one, or rescind the recommendations for healthy kids.

“That was what I was hoping was going to happen, but that didn’t happen at all,” she said. “Why would they keep pushing it and not investigate it? It just seemed so irresponsible and dangerous to me.”

Calls for Pause

While the CDC maintained that all people aged 12 and older, regardless of health and other factors, should get vaccinated, a growing number of doctors and other experts voiced opposition to the one-size-fits-all approach.

That included Margery Smelkinson, an infectious disease expert with the U.S. National Institutes of Health’s National Institute of Allergy and Infectious Diseases.

“Why not pause Pfizer for kids like we did JnJ for adults? Or consider one dose? Why the rush for such a low risk population?” Ms. Smelkinson wrote on Twitter on June 2, 2021.

Dr. Vinay Prasad, a California epidemiologist, was another, calling myocarditis “a clear and large safety signal in young men.”

Some other doctors and health authorities, though, sided with the CDC.

“The fact that you have a case where there may be a link to the vaccine, and at the same time there are tens of thousands of other vaccinees that ended up being safe, this does not justify a pause,” Dr. Ofer Habakkuk, director of the cardiology hospitalization department at Tel Aviv Sourasky Medical Center in Israel, told The Epoch Times.

While Israel and the United States did not waver from their aggressive vaccination campaigns, some countries pushed off clearing the shots for young people or restricted their usage after the emergence of myocarditis cases. In Hong Kong, for example, authorities scaled back recommendations from two doses to one. They saw the number of myocarditis cases plunge.

A medic prepares a dose of the Pfizer-BioNTech COVID-19 vaccine at a nursing home in Netanya, Israel, on Jan. 5, 2022. Jack Guez/AFP via Getty Images

Dr. Andrew Bostom, a U.S. heart expert, also in 2021 called for officials to pause vaccination for young people until the myocarditis matter was examined more closely. Dr. Clare Craig, a British pathologist, co-authored the call.

“We were calling for a moratorium until a study was done,” Dr. Bostom told The Epoch Times.

A prospective study that would measure markers of heart health prior to vaccination and again after vaccination, as has been done for the smallpox vaccine, would be important to shed insight on the problem, Dr. Bostom said.

“I think right then we should have done trials with young healthy folks,” Dr. Koka. “There would have been equipoise, meaning there were enough parents that would have said ‘okay, go ahead, we don’t know, so we will allow our kids to be randomized to see what the side effect profile is.’”

No U.S. researchers appeared to finish prospective studies before 2023. The U.S. National Institute of Allergy and Infectious Diseases, which would be the most likely institution to fund prospective studies and was led until late 2022 by Dr. Anthony Fauci, did not respond to a request for comment.

The FDA did require Pfizer and Moderna to launch studies of post-vaccination myocarditis when approving the vaccines. The results of those studies have not been made public as of yet. Pfizer’s end date was pushed back while it’s unclear whether Moderna met its deadline. The FDA referred a request for comment to Moderna, which did not return a query.

Undercutting the Narrative

Only a small number of prospective studies have been completed to date.

Students in Thailand were measured before and after receiving a second dose of Pfizer’s vaccine. Researchers found that 29 percent of the youth experienced cardiovascular effects, and detected seven myocarditis or pericarditis cases among the 301-person cohort.

People are seated while waiting to receive a dose of COVID-19 vaccine at a mass vaccination site in Bangkok on June 7, 2021. Sirachai Arunrugstichai/Getty Images

One percent of students in Taiwan measured before and after a second shot had abnormal echocardiogram results and 17 percent reported at least one cardiac symptom.

Other researchers performed prospective studies among vaccinated people before and after a booster.

In Israel, researchers found evidence of heart injury in two of 324 participants. In Germany, researchers detected a person with pericarditis in a cohort of 41 volunteers. In Japan, two people in a cohort of about 3,800 people had myocarditis. And in Switzerland, one in 35 health care workers had signs of heart injury.

The only U.S. prospective study to date focused on the vaccine’s impact on vascular function in adults. It found that a second dose increased the number of symptoms.

Additional papers have outlined deaths from post-vaccination myocarditis, including sudden deaths, as early as 2021.

Estimated rates of post-vaccination myocarditis, meanwhile, increasingly grew.

The CDC initially said 62.8 cases per million second doses were reported among male adolescents. Later in 2021, two sets of Israeli researchers reported 107 to 136 cases per million second doses among young males.

The FDA said in late 2021 that the excess risk of myocarditis among males aged 16 or 17 approached 200 cases per million shots. A group of U.S. researchers soon after pegged the incidence as 195.4 cases per million second doses among males aged 12 to 39. They found patients that were “overlooked” by CDC researchers.

The CDC in early 2022 reported that the rate of reported cases had climbed to 105.8 per million second doses among males aged 16 or 17 while Israeli officials reported rates as high as 153 cases per million second doses among males aged 16 to 19.

Nordic researchers soon after reported excess rates as high as 274 per million among young males who received two shots.

Some researchers grouped cases by vaccine type and discovered Moderna recipients were more likely to experience myocarditis.

Canadian researchers, for instance, found that excess cases after a second dose were 162 per million for young, male Moderna recipients, compared to 31 per million for Pfizer recipients in the same population. Cases were also higher among women who received Moderna’s shot.

Researchers in England found 14 excess cases per million second Pfizer doses among males under 40, and 97 excess cases after second Moderna doses among the same population.

Moderna’s primary series was larger. It was composed of two doses containing 100 micrograms each. Each dose of Pfizer’s series contained 30 micrograms.

As Risk Grows, Benefits Shrink

The observational data, case reports, and prospective studies added more clarity to the myocarditis risk. It was more common than originally thought and a problem that didn’t always resolve quickly. The vaccines, meanwhile, have performed worse against newer variants.

After Dr. Hoeg’s paper, the FDA found that in one of six modeled scenarios, the projected number of myocarditis and pericarditis cases caused by Pfizer’s vaccine would exceed COVID-19 hospitalizations and deaths among 5- to 11-year-olds. The outlier scenario projected 156 excess myocarditis hospitalizations, compared to just 21 prevented COVID hospitalizations, among males aged 5 to 11, and 28 excess myocarditis hospitalizations compared to 21 prevented COVID hospitalizations among females of the same age group.

The presentation resulted in the agency authorizing, and the CDC recommending, Pfizer’s shot for the age group.

A paramedic transports a COVID-19 patient outside the Royal London Hospital in London on Jan. 5, 2021. Justin Tallis/AFP via Getty Images

Many researchers were saying the benefits of the vaccines outweighed the risks for all age groups, but not all. As early as the summer of 2021, German researchers said that the risk-benefit calculus for children “need[s] to be considered carefully, since young people are at a very low risk for severe COVID-19 infection even without vaccination.”

Another FDA analysis in the spring of 2022, projecting at least 80 percent effectiveness against hospitalization—an outdated figure—estimated COVID-19 vaccines would cause more myocarditis cases than prevented hospitalizations in males aged 16 or 17 in two of three scenarios. The agency, as usual, did not stratify by underlying health or prior infection, and did not include any risks outside of myocarditis.

That same month, the CDC published a non-peer-reviewed paper alleging cardiac complications were higher after COVID-19 infection than after vaccination. “These findings support continued use of mRNA COVID-19 vaccines among all eligible persons aged ≥5 years,” CDC researchers said.

The methods they used drew widespread scrutiny, including how they only studied people with an official COVID-19 diagnosis. That left out children who were tested at home or not tested due to mild symptoms.

Later in 2022, U.S. researchers, including Dr. Hoeg, estimated that for every hospitalization prevented by boosters among young, healthy people, 1.5 to 4.6 myocarditis cases were caused. Their analysis incorporated the waning effectiveness of vaccines amid the Omicron variant.

“A lot of parents were reaching out to us as a group, saying, ‘hey, I’ve looked through the scientific literature ... I’m worried about my young, healthy, athletic son, getting myocarditis or suffering some other adverse event,’” Kevin Bardosh, one of the researchers, told The Epoch Times.

The most recent FDA risk-benefit comparison for Moderna’s shot among people aged 18 to 25 estimated the vaccines would cause 58 to 207 hospitalizations for myocarditis and prevent 635 to 5,957 hospitalizations. It was published in June but used no data from 2023.

The models often rely on data from months prior, helping to overestimate benefits. Data have shown the vaccines have performed much worse against newer variants, with signs that effectiveness turns negative.

“You always find out more risks down the road,” Dr. Hoeg said. “And then of course we learned that the benefits didn’t last as long as anyone seemed to think they would.”

The CDC has defended its risk-benefit estimates.

They “provided a rapid, flexible alternative to more traditional modeling methods, supplying crucial estimates of the benefit-risk balance of vaccination in an emergency setting,” officials wrote in a paper published in July 2023.

The researchers did acknowledge the lack of stratification by prior infection and other limitations.

Boosters Rolled Out

Authorities initially promoted a primary series, or two shots of the Moderna or Pfizer vaccine, as protective, with no indication of future doses.

Data emerged in mid-2021 that the vaccine-bestowed protection was eroding over time.

People receive the Pfizer COVID-19 vaccine a vaccination center in Salisbury, England, on Jan. 20, 2021. Finnbarr Webster/Getty Images

The FDA on Sept. 22, 2021, authorized a Pfizer booster for many Americans 18 and older to try to restore some of the lost protection. It relied on data from a trial of just 306 people, among whom no cases of myocarditis were reported. No efficacy data was provided.

The FDA said that the risk of myocarditis after booster shots was not known while Israeli authorities said they already had a case of myocarditis after starting the booster earlier that fall. One person in Pfizer’s booster trial suffered a heart attack, one symptom of myocarditis.

CDC officials recommended the booster for certain populations. They projected one million boosters would cause up to 26 myocarditis cases in the 18- to 29-year-old population while preventing up to 114 hospitalizations and as few as zero hospitalizations. They estimated that 8,738 people in the population would need a booster to prevent a single hospitalization.

Booster availability was later expanded to all populations aged 5 and older, including 16- and 17-year-olds, by inferring effectiveness and safety from an adult population. There was no mention of myocarditis. Moderna’s booster was also authorized and recommended based on a trial that included a case of pericarditis. Dr. Walensky said the COVID-19 vaccines “are safe and effective.”

Ben Cutler, a Boston resident, was among those who received a booster after the clearance and recommendation. He received a Moderna booster on Dec. 14, 2021. He was 26.

Mr. Cutler suffered the worst pain of his life and required hospital care. He was diagnosed with myopericarditis from the shot.

While other countries took a cautious approach with the booster, “for some reason in the U.S. they just want to give it to everyone without any real data to show that it has any benefit,” Mr. Cutler told The Epoch Times.

Data from VAERS later showed the rate of reported myocarditis cases among males aged 16 or 17 was 188 per million Pfizer boosters—higher than the rate after a second dose. The reported rates among 18- to 29-year-old males after a booster dose were also higher than projected, with 36.4 cases per million Pfizer boosters and 64 per million Moderna boosters.

South Korean researchers later calculated a rate of 82 cases per million Pfizer boosters and 31 per million Moderna boosters among people 18 and younger.

Because the protection from boosters ended up fading over time, and the vaccines have performed worse against Omicron and its subvariants, authorities later took a series of steps, including authorizing second boosters for some, clearing third boosters for others, and recommending newly formulated vaccines. They just cleared and recommended yet another round of shots.

Laboratory technicians package vials of COVID-19 vaccines at a manufacturing facility in Anagni, Italy, on Sept. 11, 2020. Vincenzo Pinto/AFP via Getty Images

Long-Term Problems and Deaths

Vaccine-induced myocarditis has caused both long-term problems and deaths, researchers have confirmed.

Canadian researchers on March 9, 2023, for example, reported that in a group evaluated two months after myocarditis following vaccination, some patients had persistent inflammation and edema.

Symptoms persisted in eight of 44 patients studied in Italy, researchers there reported soon after. Researchers also detected heart edema, or excess fluid, in eight of 29 patients on whom followup imaging was conducted.

A number of other papers have identified persistence of symptoms, inflammation, edema, and/or LGE.

Some patients still haven’t recovered to this day.

Followup scans have also revealed scarring on the heart months after vaccination.

Deaths, meanwhile, began being reported in early 2021.

At least some have since been confirmed as being caused by vaccine-induced myocarditis.

The certifier who examined 24-year-old George Watts Jr., a college student in New York, wrote on Mr. Watts’ death certificate that the death was due to “COVID-19 vaccine-related myocarditis.”

Joseph Keating, 26, of South Dakota, died from myocarditis, according to his death certificate, with his recent Pfizer booster shot listed as contributing.

Mr. Keating’s sister Kaylee Koch, told The Epoch Times that the family tried contacting the CDC but have never received a response. The CDC did not respond to a request for comment.

Other young people have died shortly after COVID-19 vaccination with causes similar to or related to myocarditis. Ernest Ramirez Jr., a 16-year-old in Texas who was pronounced dead after collapsing five days following a Pfizer jab, died from an enlarged heart, according to his autopsy. Myocarditis can cause an enlarged heart.

Researchers in other countries have also confirmed deaths caused by myocarditis following vaccination.

People wait in line at a vaccination site in Washington on Nov. 29, 2021. Jim Watson/AFP via Getty Images

Japanese researchers, for instance, analyzed autopsies from 54 deaths potentially caused by vaccine-related adverse effects and determined three were caused by the vaccine-induced myocarditis.

U.S. researchers who recently reviewed 325 autopsies found in a preprint paper that COVID-19 vaccination caused or contributed to about three-quarters of those deaths, including nine involving myocarditis.

The CDC has declined to provide autopsy reports obtained by the agency while probing deaths reported to VAERS following COVID-19 vaccination. It has also claimed it does not have any records of deaths caused by vaccine-induced myocarditis, and does not have any data on deaths after COVID-19 vaccination from the Vaccine Safety Datalink.

The FDA rejected a request for the results of autopsies conducted on people who died after receiving a COVID-19 vaccine, and turned down an appeal in the matter.

Megan Redshaw and Katherine Wu contributed to this report.