On June 23, an advisory committee to the Centers for Disease Control and Prevention met to discuss, among other topics, vaccine-related cases of myocarditis, which have hospitalized hundreds of adolescents. Evidence of a correlation between the condition, an inflammation of the heart muscle, and the vaccines had been mounting for months. Numerous countries had altered or withheld recommendations for pediatric vaccination, with some citing an ambiguous risk-benefit. One day after the committee meeting, however, CDC director Rochelle Walensky went on TV and calmly reassured viewers that there was nothing to worry about: Vaccinating kids age 12 and up, at the full dosage and same schedule as adults, should continue with alacrity.
Walensky cited a string of statistics that showed “the benefits of vaccination far outweigh any harm.” But some epidemiologists, public health experts, pediatricians, cardiologists, and other scientists dispute the CDC’s numbers, characterizations, and conclusion. The agency, they variously contend, is both exaggerating the risks of Covid-19 to young people and underplaying the potential risks of the vaccine to them. Much data that would support the CDC’s declarations are either unknown, unrevealed, or far messier than the agency and its director portray. And the data that are known and clear have been projected through a specific lens with blunt certainty. The absolute risk of the vaccine still appears to be extremely small for young people but, on balance, when the data are seen through a different frame, the relative individual risk from vaccination, particularly for healthy young males, may be higher than it is to not be vaccinated at this time.
There is no debate among most experts critical of the CDC about the value of vaccines on a societal level to help usher in the end of the pandemic, which is the ultimate goal of the vaccine. Rather, the matter at hand is the CDC’s messaging, which fails to help parents and children make properly informed decisions about the vaccines on an individual level. As Stefan Baral, an epidemiologist and physician at Johns Hopkins, recently tweeted, “One can be both very pro-Covid-19 vaccination and also be worried about the individual risk:benefit profile of Covid-19 vaccines in <16 yo.”
First, the link between the mRNA vaccines and myocarditis, particularly in young males, is sufficiently clear that the FDA revised its vaccine fact sheets to include a warning about it. As of June 11 (the latest date most data were collected for the meeting), 128 cases within seven days of the second dose had been reported in boys aged 12 to 17, when the CDC’s expected number for that same population was zero to four cases. VAERS, the reporting database for vaccine-related adverse events that these statistics are drawn from, has limitations. Some portion of the events reported may be unrelated to the vaccines. But the differential between expected and observed cases within certain cohorts is the statistical equivalent of a blaring siren. (A detailed analysis in Israel estimated the incidence of myocarditis following vaccination in young males to be around one in 5,000, equating to 200 cases per million.)
The CDC, however, wants to make the case that the arresting numbers above only present an illusion of bad stakes for young people, in particular young males. On Good Morning America on June 24, Walensky said, “If we have a group of 12- to 17-year-olds who we’re working to vaccinate over the next four months and can vaccinate 1 million of them, we could expect 30 to 40 of these mild self-limited cases of myocarditis … If we were to vaccinate all 1 million we would avert 8,000 cases of Covid, 200 hospitalizations, 50 ICU stays, and one death.”
How did the CDC arrive at “30 to 40” cases? In the advisory committee meeting a slide was presented that showed that within 7 days following the second dose males aged 12 to 17 had a rate of 62.75 myocarditis cases per million, whereas females had a rate of 8.68. Averaging the two rates yields 35.72 cases. Yet the rate for young males is more than seven times that of young females. Lumping together two easily delineated cohorts, especially when data show a wildly disproportionate risk for one group, as Walensky did, “is epidemiologically misleading,” said Tracy Hoeg, a physician and epidemiologist who coauthored a study published by the CDC this year, and who is researching myocarditis data with Allison Krug, also an epidemiologist. “If there is a clear pattern that differs from one sex to another,” Hoeg said, reporting the two rates together “obscures the true findings.” It both downplays the risk to young males while making the risk seem higher than it is for young females. A summary slide shown at the meeting similarly, yet even more consequentially, merges not just sexes but also multiple age cohorts, creating a macro coed group of 12– to 39-year-olds, with a rate of 12.6 cases per million second doses, further burying the higher rate (of 62.75 cases) of myocarditis for young males.
Describing the cases without exception as “mild” may also be misleading. A review of myocarditis reports of young males in VAERS finds numerous cases with potentially serious symptoms, including reduced ejection fraction (the measurement of blood pumped out of the heart) as low as 35 percent, which can indicate heart failure; myocardial fibrosis (a scarring of the heart, which also can lead to heart failure); and patients on vasopressors to raise low blood pressure. None of these conditions would typically be considered mild, said Adam Zucker, a cardiologist at Massachusetts’ Brigham and Women’s Hospital.