A recent collaboration between federal agencies and Kaiser Permanente funded by the Centers for Disease Control (CDC) found severe health risks in the first three weeks after receiving an mRNA vaccine from either Pfizer-BioNTech or Moderna were no more common compared with 22-42 days later. The study, titled “Surveillance for Adverse Events After COVID-19 mRNA Vaccination,” was published on September 3 in JAMA Network under the direction of lead author Nicola Klein MD, Ph.D., Kaiser Permanente Vaccine Study Center’s Director and principal investigator of the CDC’s Vaccine Safety Datalink (VSD) COVID-19 rapid cycle analysis.

The study follows a March 2020 announcement of a partnership between Kaiser Permanente and the CDC Foundation—a nonprofit organization whose stated mission is to “mobilize philanthropic and private-sector resources to support the work of the Centers for Disease Control and Prevention (CDC).” 

Results of the Statistical Study

Using safety surveillance data from VSD, the study sifted through the health records of 6.2 million patients to monitor 23 serious outcomes each week. It was comprised of 12,506,658 individuals (representing 3.6% of the US population and included all ages, with roughly 16% aged 65 years or older and 20% younger than 18 years) and covered by eight data-contributing health plans (Kaiser Permanente: Colorado, Northern California, Northwest, Southern California, and Washington; Marshfield Clinic; HealthPartners; and Denver Health), representing 3.6 percent of the US population.

The research studied twenty-three potential health effects chosen for a variety of reasons, including having been involved in previous vaccine study, that they were of particular concern as an effect of COVID-19, that they were seen during the COVID-19 clinical trials, or that public health officials added them after reported increased cases among vaccinated people. Outcomes tracked included neurological disorders such as encephalitis and myelitis, seizures, and Guillain-Barré syndrome. Also tracked were cardiovascular problems such as acute myocardial infarction, stroke, pulmonary embolism, and others, such as Bell’s palsy, appendicitis, anaphylaxis, and multisystem inflammatory syndrome.

VSD searched millions of patient medical records electronically. Analysts carried out chart reviews of specific health outcomes to verify the medical problem and evaluate whether it started before or after vaccination. Vaccine Safety Datalink researchers then used statistical analysis to determine whether the number of incidents was above a certain threshold or “signal.” They concluded that none of the target health outcomes reached the signal, though the findings were less precise for some outcomes because of the small numbers of cases. The authors stated VSD safety surveillance is continuing, which will improve the accuracy of estimates for those outcomes.

The study, which summarized findings from mid-December 2020 through June 26, 2021, is the VSD’s first comprehensive report of its safety surveillance of the Pfizer and Moderna mRNA vaccines. According to the researchers, mRNA vaccines were not linked with an increased risk for over twenty serious outcomes up to 42 days post-vaccination.

“These results from our safety surveillance are reassuring,” said Klein, who is also a senior research scientist with the Kaiser Permanente  Division of Research. Kaiser Permanente reported the study was designed to analyze patients as similar to one another as possible to lessen the number of factors that could complicate the results. The authors added a comparison group of unvaccinated patients in a supplemental analysis.

Tom Shimabukuro, MD, who leads vaccine safety for the COVID-19 response and is deputy director of CDC’s Immunization Safety Office, said of the study:

“The results of this study are a great example of how seriously CDC takes vaccine safety and how thorough and transparent we are in our safety monitoring efforts. It is our top priority to do the science and communicate quickly and clearly with healthcare providers and the public, as COVID-19 vaccines continue to undergo the most intensive safety monitoring in U.S. history. Getting vaccinated remains the best way to protect yourself and your loved ones against a virus that has taken millions of lives.”

What is Vaccine Safety Datalink (VSD)

The Vaccine Adverse Event Reporting System (VAERS) is cosponsored by the Food and Drug Administration (FDA) and the CDC. Underreporting of adverse events leaves the voluntary reporting system severely lacking in capturing reliable data. According to the CDC website, since 1990, the VSD has monitored and evaluated the safety of vaccines based on questions or concerns raised from medical literature and reports to the VAERS. 

The VSD website states, “When there are new vaccines that have been recommended for use in the United States or if there are changes in how a vaccine is recommended, the VSD will monitor the safety of these vaccines.” JAMA explains that the VSD conducts postmarketing evaluations of vaccine safety within a defined population. A primary analytic approach for postmarketing surveillance by VSD is rapid cycle analysis (RCA), whereby the observed number of adverse events is compared with the expected number of events, with the expected number of events determined from previous data, a concurrent comparison control group, or self-control methods.

Kaiser Permanente points out that the CDC’s VSD is “the nation’s premier active surveillance system for vaccine safety.” As reported by UncoverDC, on May 1 of this year, as breakthrough COVID-19 cases continued to rise, the CDC stopped tracking COVID-19 in vaccinated people unless they are hospitalized or die. The CDC’s decision to stop tracking this critical information creates a disturbing lack of transparency on COVID-19 statistics in vaccinated vs. unvaccinated persons, hospitalizations, and other relevant data. It is unclear if VSD will soon provide this information.

Study Limitations & Potential Conflicts of Interest

The CDC and Kaiser Permanente interim analysis of mRNA COVID-19 vaccine surveillance using VSD data has stated limitations, including limited statistical power. There is the possibility the risk could be underestimated and the broad categories capable of hiding specific outcomes. Additionally, the study spans just six weeks post-vaccination and does not consider the possible long-term risks of vaccination. Furthermore, while the study included other medically attended outcomes, it could have underestimated risk.

In the early 1990s, Congress created two federally chartered medical foundations—the Foundation for the National Institutes of Health (FNIH) and the CDC Foundation—to raise private funds to support federal biomedical and health research. 

Controversy about the transparency of “the source and amount of all gifts” has surrounded the two low-profile foundations, which have funneled nearly $2 billion over the past twenty-five years to the National Institutes of Health (NIH) and the CDC for research, clinical trials, training, and educational programs. In 2018, legislators on the House of Representatives appropriations subcommittee (that oversees the NIH and CDC) expressed concern that the FNIH and CDC Foundation were not adhering to disclosure rules spelled out in the Public Health Service Act (PHSA). 

The legislators pointed out that it’s not acceptable for the foundations to hide the identity of donors who have attached strings to their gifts by labeling them as “anonymous.” For example, in 2016, FNIH listed eight donors who gave more than $2.5 million each, its top category. However, a separate report FNIH filed with the IRS exposed that one of those donors gave $19.1 million – that donor turned out to be the Bill & Melinda Gates Foundation. Offering specific examples of the lawmakers’ issues with transparency, a June 2018 report in Science describes:

NIH Director Francis Collins canceled a $100-million study on the effects of moderate alcohol drinking that was largely funded by the spirits industry after an investigation found NIH staff had improperly solicited industry directly and shaped the study to satisfy industry interests. Collins also killed a plan to partner with pharmaceutical companies on a $400 million study of opioid dependency after an outside panel warned of potential conflicts. The CDC Foundation has come under fire in recent years for how it has handled corporate donations (such as Coca-Cola funding the agency’s anti-obesity campaign), and as a result, has severed connections with some donors.