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An analysis published earlier this month in Pediatrics concluded the COVID-19 mRNA vaccines are safe and effective in preschool-age children — a conclusion trumpeted by media outlets such as Parents and Medscape.

But the study, conducted by Kaiser Permanente researchers with funding from the Centers for Disease Control and Prevention (CDC), raises more questions than it answers.

Researchers followed children (mostly 4 years old or younger) who collectively received more than 245,000 doses of either the Pfizer or Moderna mRNA products and “found no indications of serious side effects,” according to a Kaiser Permanente news release.

Using a form of surveillance monitoring known as rapid cycle analysis, investigators performed weekly sequential analyses for 19 safety signals, including myocarditis, pericarditis, seizures, heart attack, Bell’s palsy, neurological inflammatory conditions, anaphylaxis and several others.

The study period was from June 2022 to March 2023.

Instead of using a comparable group of unvaccinated children as the control, the authors compared adverse events occurring 1-21 days after vaccination in one group, with outcomes among children in another group who had received the shot at some point between 22 and 42 days previously.

Time since inoculation was the only distinguishing feature, and the only factor that might account for inter-group differences.

The study, therefore, boils down to the question of whether children who received an mRNA shot about 10 days previously experienced more or fewer adverse events than children who received their jab about 32 days previously.

Data were mined from the Vaccine Safety Datalink (VSD), a repository of patient data from eight private healthcare systems, which included five Kaiser Permanente regions and three other large health entities.

Up to three doses of the Pfizer-BioNTech product were given to 135,000 children, ages 6 months to 5 years, while 112,000 children, ages 6 months to 6 years, got the Moderna gene therapy.

Subject demographics more or less reflected the populations served by these healthcare companies.

The authors wrote that their safety surveillance over nine months “did not detect a safety signal for any outcome during the 21 days after vaccination. Importantly, no cases of myocarditis or pericarditis occurred after vaccination.”

The accompanying press release framed the conclusion even more positively. According to corresponding author Dr. Nicola Klein:

“Parents can be assured that this large study found no serious side effects from the mRNA vaccines. … Parents can protect their young children from COVID-19 in the same way they vaccinate their children to protect from other serious childhood diseases.”

Perhaps anticipating the long list of questions regarding their work, the researchers discussed the potential limitations of their analysis, which they said included:

  • Reduced statistical power, particularly for rare outcomes.
  • Low vaccine uptake in the evaluated age group (“only” 24.7% of the eligible population received at least one shot).
  • Surveillance did not include “all potential safety concerns.”

And the kicker:

“We may have underestimated or missed potential safety concerns if the biologically plausible risk interval for an outcome differed from our specified risk interval.”

Together, the choice of control group and the time period selected almost guaranteed “reduced statistical power,” particularly when comparing the two groups.

In a 2022 paper Klein noted reports from “worldwide” sources of myocarditis/pericarditis after mRNA COVID-19 treatments “especially among younger male persons [italics mine] 0 to 7 days after receiving dose 2.”

Although the incidence of heart inflammation was low in the 0-5 age group for the Pfizer product (14.4 per million doses, mostly after the second shot), the incidence of serious cardiac events rose markedly for older groups.

No data were available in the 2022 study for the Moderna shot.

For 18- to 29-year-old males — the youngest age group for which both Pfizer and Moderna data were available — Klein reported, based on VSD numbers, a cumulative myocarditis/pericarditis incidence of 135 cases per million for children who had received the two injections plus the booster.

For the Moderna product, the incidence was 185 per million. For females, the rates were about 10 per million for both mRNA shots.

Given the serious long-term consequences of heart inflammation, and its known occurrence among vaccinated teenagers and young adults, one wonders at the wisdom of giving mRNA shots to children who are even younger than those known to get sick from the treatments.

COVID-19 itself has been blamed for the rise in heart inflammation, but a search for data from very early in the pandemic, before this storyline emerged (possibly to hide the incidence of “vaccine” injuries), shows this to be a red herring.

A 2022 Italian study comparing myocarditis/pericarditis incidence pre- and post-COVID-19 reported that the annual incidence of myocarditis was significantly higher before the pandemic than during, with a rate of about 80 per million “pre” and 60 per million “during.”

The authors made a point to emphasize that “the incidence of myocarditis was significantly lower in COVID than in PRECOVID in the class of age 18-24 years” than for their general study population, which averaged 40 years of age.

The incidence of pericarditis was unchanged between the two time periods, at about 45 per million.

Comparing data from two far-flung studies should be undertaken with caution. However, the difference between a baseline of fewer than 60 cases per million for 18- to 24-year-old adults (the Italian study) and the 185 per million for “male persons” between 18 and 29 post-mRNA treatment (Klein et al.) clearly and inconveniently shatters the “safe and effective” narrative.

The lack of statistical power in Klein’s 2023 study, despite a very large “denominator” (total patients studied), is almost certainly due to the relatively small number of cases — which is exactly what one would expect when uncommon (but serious) side effects over such short time periods are compared.

True, this is an apples-to-apples comparison — but in this case, investigators pretty much used the exact same apples and reported their similarities as somehow noteworthy.

Klein’s data source(s) raise additional questions. Although the VSD is connected to the national Vaccine Adverse Event Reporting System (VAERS), how much of her raw data came from VAERS and how much came from VSD is unclear.

Eleven of VSD’s 13 participating commercial and academic hubs are “data reporting sites” whose contributions presumably include vaccine side effect reports.

The concern here is about motives and incentives. VAERS data are based mainly on self-reporting and are known to be gross underestimates of the actual number of incidents.

By contrast, hospitals and healthcare systems, e.g. those participating in VSD, were robustly incentivized to promote and administer the COVID-19 shots.

Along those lines, note that one author “received funding from Janssen Vaccines and Prevention for a study unrelated to coronavirus disease 2019 vaccines.” And lead investigator Klein “received grants from Pfizer for coronavirus disease 2019 vaccine clinical trials and from Merck, GSK, and Sanofi Pasteur for study work unrelated to the current study work.”

The rationale for immunizing children against COVID-19 has been hotly debated since the shots were first available to older adults in late 2020.

But by the time these treatments were authorized for children, it was already clear that kids do not get very sick from COVID-19 and are not a significant source of infection, either for the community or for “grandma” in her rocking chair at home.

As of early 2021, with the huge wave of Delta-variant fatalities in freefall, the number of U.S. pediatric COVID-19 deaths reported by the CDC was close to zero, both in terms of absolute cases and as a percentage of all deaths.

Yet in her interview with her institution’s media department, lead author Klein said:

“Even as the COVID-19 emergency has ended, we know that the coronavirus poses a long-term, serious threat to all ages, including children. Vaccinating children against COVID-19 benefits them by reducing the burden of illness, avoiding spreading the virus to family and others, and mitigating the small but real risk of serious illness.”