CLAIM: Repeated vaccination weakens the immune system, potentially making people susceptible to repeated COVID-19 infections, as well as life-threatening conditions such as cancer.

What is the claim about?

This claim emanates from a November 3, 2023 report in the Epoch Times titled “Repeated COVID-19 Vaccination Weakens Immune System: Study” which has generated almost 7,200 shares online as of August 2024 and claims, “Multiple doses of the Pfizer or Moderna COVID-19 vaccines lead to higher levels of antibodies called IgG4, which can provide a protective effect. But a growing body of evidence indicates that the ‘abnormally high levels’ of the immunoglobulin subclass actually make the immune system more susceptible to the COVID-19 spike protein in the vaccines.”

The article then goes on to cite a study published in 2023 by the journal Vaccines which states, “In sum, COVID-19 epidemiological studies cited in our work plus the failure of HIV, Malaria, and Pertussis vaccines constitute irrefutable evidence demonstrating that an increase in IgG4 levels impairs immune responses.” That study further explains, “Increased IgG4 synthesis due to repeated mRNA vaccination with high antigen concentrations may also cause autoimmune diseases, and promote cancer growth and autoimmune myocarditis in susceptible individuals.”

Why the conclusion is misleading

First, it is important to note that while the Epoch Times headline implies that receiving any COVID-19 vaccine will weaken the immune system, it omits the key fact that the experiments showing increases in IgG4 antibodies involved individuals who only received mRNA vaccines, such as the ones from Pfizer or Moderna. The two other types of COVID vaccines approved by the FDA at the time, the vector-based vaccine manufactured by Johnson & Johnson and AstraZeneca, and the protein subunit vaccine produced by Novavax, were not studied by the scientists cited in the Vaccines paper. As such, the alarmism embodied in that headline better serves to maximize clicks and views rather than sharing a more accurate account of a narrower and nuanced piece of science research news.

After enticing the reader with a scary and not-quite-reliable headline, the author quickly ups the ante. After citing the aforementioned research, he implies that people who receive mRNA vaccines are at risk from an array of other serious illnesses, or even death, by citing two studies that “detected higher levels of IgG4 in people who died with COVID-19 when compared to those who recovered.”

So does this mean that people who received repeated mRNA vaccines will automatically see their IgG4 antibodies spike, thus putting them in harm's way?

Other studies on IgG4 antibodies report similar results, but different conclusions

A look at other findings from various studies suggests that the claims that mRNA vaccines weaken immune systems and thus can lead to cancer and other deadly diseases are hardly conclusive, and indeed may be sensationalist and dangerous. For example, at least two further studies did report increased IgG4 antibodies in those that received repeated mRNA vaccines, but their conclusions were much more sober and studied, mostly saying that more research needs to be done. 

A study in Science Immunology also showed an increase in the IgG4 antibody on individuals who received repeated mRNA vaccinations. However, the paper noted that IgG4 antibodies had overall benefits for individuals and “in practical terms, they are unlikely to compromise immunity in vaccinated patients at this time.”

In results from a study in Hungary published by Scientific Reports, researchers analyzed healthcare workers who had been vaccinated with either vector-based (Sputnik, AstraZeneca) or mRNA-based (Pfizer-BioNTech, Moderna) vaccines against COVID-19 and found higher levels of the IgG4 antibody in those who had repeated mRNA vaccinations. However, the study makes no claim that repeated mRNA vaccinations weaken a person’s immune system and lead to other diseases and indeed also recommends that further research be conducted.

Another study published in May 2023 by the American Society of Microbiology came to a similar conclusion, finding that “Despite IgG4’s high levels in certain circumstances, the clinical picture remains not significantly different than when levels are within normal limits, as it appears that IgG4 is a by-product of another ongoing process. Undoubtedly, more in-depth research would shed light on the role of this new evolutionary member of the immune response.”

The American Association for the Advancement of Science had this to say on the subject, again suggesting that additional investigation is needed: “More SARS-CoV-2-specific IgG4 is not harmful. It does not create additional susceptibility to other pathogenic infections, and it does not impact the effectiveness of the vaccine. Instead, IgG4's elevated presence is noteworthy, because not much is known about how the subtype's levels transform during infection in the first place.”

Sources

1. Zachary Stieber, “Repeated COVID-19 Vaccination Weakens Immune System: Study,” The Epoch Times, June 1, 2023.
2. Vladimir Uversky et al., “IgG4 Antibodies Induced by Repeated Vaccination May Generate Immune Tolerance to the SARS-CoV-2 Spike Protein,” Vaccines, April 2, 2023.
3. Andrew Moura, “Assessment of avidity related to IgG subclasses in SARS-CoV-2 Brazilian infected patients,” Nature, September 1, 2021.
4. Shiv Palai,  “Is it bad, is it good, or is IgG4 just misunderstood?,” Science Immunology, February 7, 2023
5. Petra Kiszel, “Class switch towards spike protein-specific IgG4 antibodies after SARS-CoV-2 mRNA vaccination depends on prior infection history,” Nature, August 13, 2023.
6. Kamran Kadkhoda, “Post-COVID mRNA-vaccine IgG4 shift: worrisome?,” mSphere, May 16, 2023.
7. Abigail Eisenstadt, “Repeat SARS-CoV-2 mRNA Vaccination Tied to Rise in Unexpected Antibody Subset,” American Association for the Advancement of Science, January 13, 2023.