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COVID-19 vaccines don’t weaken the immune system; Lancet study misrepresented in Virology Journal comment

Posted on:  2022-07-28

Key takeaway

No scientific evidence supports the claim that COVID-19 vaccination weakens the immune system. On the contrary, vaccination helps our immune system to better defend itself against infection. Large-scale clinical trials and scientific studies found that the benefits of the COVID-19 vaccines outweigh their risks.

Reviewed content


Lancet study showed that vaccinated people have lower immune function than unvaccinated people; COVID-19 vaccines suppress the immune system

Source: Fox News, The Hodgetwins, Kenji Yamamoto, Tucker Carlson, 2022-07-21

Verdict detail

Misrepresents source: The Lancet study cited in the video examined how COVID-19 vaccine effectiveness wanes over time. The study didn’t examine immunity to infectious diseases in general nor did it find that COVID-19 vaccines weaken the immune system.
Misleading: The review article by Seneff et al. provided no evidence that COVID-19 vaccines weaken the immune system.

Full Claim

A Lancet study “showed that immune function among vaccinated individuals 8 months after the administration of two doses of COVID-19 vaccine was lower than that among the unvaccinated individuals”; “it's looking likely that the vaccine might suppress the immune system”


On 21 July 2022, Fox News host Tucker Carlson claimed that “it’s looking likely that [COVID-19] vaccines suppress the immune system”. To support that assertion, Carlson cited a review article by Seneff et al. and a comment in Virology Journal by cardiologist Kenji Yamamoto. Carlson’s news segment was shared by political commentators The Hodgetwins and cardiologist Peter McCullough, who previously made false claims about COVID-19 and COVID-19 vaccines. Political commentator Ben Swann also made the same claim as Carlson in this video on Facebook, citing the same articles.

The claim isn’t new; Health Feedback already debunked this claim here, here, and here. Claims like this illustrate how scientific publishing has proven to be an effective vehicle for spreading misinformation, by lending a sheen of credibility to inaccurate and misleading claims and narratives. This review will explain how this iteration of the claim by Carlson relies on speculations that lack scientific evidence as well as misrepresentations of a study published in the scientific journal The Lancet.

Article by Seneff et al. claiming that mRNA vaccines cause health problems like cancer is based on speculations that lack supporting evidence

In a review article, Seneff et al. claimed that COVID-19 mRNA vaccines could weaken the immune system through various biological pathways and increase the risk of infection and cancer. It should be noted that its lead author is Stephanie Seneff, a computer scientist at the Massachusetts Institute of Technology, who has no training in infectious diseases or vaccines. Seneff has claimed that vaccines cause autism, a claim that has been disproven by large-scale scientific studies which have thus far shown no association between vaccination and risk of autism.

In an email to Health Feedback, Angeline Rouers, a senior research fellow at the A*STAR Infectious Diseases Labs in Singapore, stated that she found the review to be misleading and based on misinterpretation of scientific studies. The authors claimed that the innate immune response, in particular type I interferon, is suppressed because COVID-19 vaccines favor the adaptive immune response instead. However, the fact that COVID-19 vaccination promotes adaptive immunity as opposed to innate immunity isn’t surprising.

“It is normal and expected to observe different immune profiles following vaccination and infection,” said Rouers. “The vaccines provide long-term protection against COVID-19 without the sickness that comes from infection. Therefore, the immune reaction that vaccination elicits is different from that stimulated by infection.”

Furthermore, the promotion of adaptive immunity by COVID-19 vaccination doesn’t imply the suppression of the innate immune system and “has no impact on the immunity against other pathogens or against cancer,” Rouers clarified. [See Rouers’ full remarks here.]

Indeed, a group of scientists, led by oncologist Jérôme Barriere, published a reply to the review, available on the OSF preprint server, also remarking on the same issue, among others.

Barriere et al. wrote that the authors’ claim about type I interferon impairment is based on a preprint[1] showing “a differential gene expression profile in peripheral dendritic cells based on vaccinal status, but do not support the authors’ claim that there is Type I IFN suppression due to the vaccine. Reliable research shows this is simply the reaction expected from a vaccine: a high immune response without a systemic and uncontrolled inflammation”.

Jeffrey Morris, professor of biostatistics at the University of Pennsylvania, discussed the article by Seneff et al. in a Twitter thread. One of the most significant flaws in the article, he pointed out, is that it’s primarily rooted in speculation. For instance, the authors suggested that mRNA vaccination is associated with diseases like herpes zoster reactivation, liver damage, and optic neuropathy, even though there’s no evidence that a link exists.

The article also claimed to present “evidence that vaccination induces a profound impairment in type I interferon signaling, which has diverse adverse consequences to human health”. While it did discuss several biological pathways, the authors didn’t present evidence demonstrating that these pathways are actually affected by mRNA vaccines.

“In some cases, they link to other vaccines, old mRNA technology, or COVID-19 infection, but are not directly linked to mRNA vaccines,” Morris said. Interestingly, he observed that much of the evidence cited was related to severe COVID-19, meaning that “much content in this article might be better suited to a paper pointing out potential downstream dangers of severe COVID infections rather than raising alarm about mRNA vaccination”.

The authors sought to strengthen their claim about the dangers of COVID-19 vaccines by citing reports from the U.S. Vaccine Adverse Event Reporting System (VAERS). For example, the authors analyzed VAERS reports of anosmia (loss of smell) and concluded that it was a sign the vaccine caused nerve damage. However, as Morris pointed out, anosmia is common with COVID-19, whereas it isn’t with vaccination. Therefore, these cases of anosmia could be explained by a previous SARS-CoV-2 infection. But the authors ignored this possible explanation for their observation.

In support of their claim, the authors also cited the fact that VAERS reports related to COVID-19 vaccines made up the majority of reports for 2021 compared to other vaccines like the flu vaccine. However, they failed to account for differences in reporting rates between vaccines and the possibility that people are more likely to file VAERS reports after a COVID-19 vaccine than for other vaccines. A similar claim was addressed by Health Feedback here.

By analyzing VAERS reports of various “negative control events”—events we can safely exclude as being linked to vaccination—such as toothache, limb X-rays, and alopecia (hair loss), Morris found that reporting for COVID-19 vaccines is indeed disproportionately higher than for other vaccines. For example, 97.2% of reports about toothache and 88.3% of reports about limb X-rays were filed after a COVID-19 vaccine. We have no reason to believe that COVID-19 vaccines cause toothache or limb X-rays, meaning that the large proportion of reports attributed to COVID-19 vaccines are the result of people being more likely to report adverse events after COVID-19 vaccination, not because COVID-19 vaccines are harmful.

Overall, the review presented a series of speculations about how mRNA vaccines might affect health—all in favor of the narrative that COVID-19 vaccines are harmful—but without presenting direct evidence that the changes they speculated would happen actually occur.

As Morris pointed out, the review at best provides “hypotheses to validate, not principles to assume true unless disproven”. Furthermore, the responsibility for validating these hypotheses lies with the authors themselves, as Morris pointed out, but instead the authors demanded for public health authorities to prove them wrong—a typical example of shifting the burden of proof.

Comment by Yamamoto misrepresented the research and findings of a study in The Lancet by Nordström et al.

Yamamoto’s comment in Virology Journal, published in June 2022, claimed that a Lancet study, published in February 2022, showed “immune function among vaccinated individuals 8 months after the administration of two doses of COVID-19 vaccine was lower than that among unvaccinated individuals”. Yamamoto also went on to assert that “As a safety measure, further booster vaccinations should be discontinued” and that “COVID-19 vaccination is a major risk factor for infections in critically ill patients”.

However, this misrepresents the Lancet study performed by Nordström et al. The study examined the risk of SARS-CoV-2 infection, hospitalization, and death up to nine months after the second COVID-19 vaccine dose[2]. It reported that vaccine effectiveness decreased over time, meaning that the protection offered by the vaccines isn’t permanent.

It also considered that its findings “[strengthen] the evidence-based rationale for administration of a third vaccine dose as a booster, where the priority should be specific populations who are at higher risk of severe consequences of COVID-19 due to weaker and more rapidly waning vaccine-elicited immunogenicity”. This is the complete opposite of Yamamoto’s comment, which inaccurately extrapolated the findings of the study, which were related only to COVID-19, with infectious diseases in general.

Other statements raise questions about the scientific credibility of Yamamoto’s comment. In one example, he wrote that “The media have so far concealed the adverse events of vaccine administration, such as vaccine-induced immune thrombotic thrombocytopenia (VITT), owing to biased propaganda”.

This is false; on the contrary, multiple mainstream media reports about VITT exist, like these by Reuters, the BBC, and the CBC, and have received much attention from both the scientific community and the public. It’s important to keep in mind that the risk of blood clots following COVID-19 is higher than after vaccination, as a study of more than 29.1 million people in the UK showed[3].

Yamamoto also claimed that “It has been hypothesized that there will be an increase in cardiovascular diseases, especially acute coronary syndromes, caused by the spike proteins in genetic vaccines”. One of the scientific references he used to support this claim is an abstract by cardiothoracic surgeon Steven Gundry, which appeared in the medical journal Circulation in November 2021. An abstract is a brief summary of research findings, not a scientific study in itself.

Gundry’s abstract received an Expression of Concern from the journal on 24 November 2021. The notice stated that “there is no data in the abstract regarding myocardial T-cell infiltration, there are no statistical analyses for significance provided, and the author is not clear that only anecdotal data was used”. In other words, no evidence was presented for the claims made in the abstract. But Yamamoto made no mention of the Expression of Concern or the problems with the abstract.

While it is true that certain COVID-19 mRNA vaccines increase the risk of heart inflammation, in particular young men, the risk of heart inflammation and other health problems is much greater after getting COVID-19[4]. The U.S. Centers for Disease Control and Prevention estimated that teenage boys were two to six times more likely to develop heart complications after COVID-19 than after vaccination, while the risk was seven to eight times higher in young men[5].

Overall, the comment entirely misrepresented the findings of a Lancet study and emphasized the risks of COVID-19 vaccination while leaving out the fact that the risks associated with COVID-19 is much higher. It paints a misleading picture of the scientific state of understanding regarding the safety of COVID-19 vaccines. In fact, the evidence shows that it is safer to get vaccinated than remain unvaccinated.

Scientists’ Feedback

Angéline Rouers member picture

Angéline Rouers

Senior Research Fellow, A*STAR Infectious Diseases Labs

The review by Seneff et al. is misleading and based on a misinterpretation of scientific data. The review is based on independent scientific evidence which are then combined to lead to a false conclusion: mRNA vaccines weaken innate immunity, particularly interferon (IFN) response.

It is known that type I IFN, which is part of the innate immune system, is particularly important in cancer. Mutations of IFN-related genes contribute to the development of cancer and IFN is a common therapy to treat tumor growth[6]. As for COVID-19 mRNA vaccines, studies have shown that they instead favor the adaptive immune response (antibodies, memory T and B cells). Based on these observations, the authors of the review raised the concern that the innate immune response, particularly the IFN response, is suppressed following vaccination, in contrast to strong inflammation during infection.

However, it is normal and expected to observe different immune profiles following vaccination and infection[1]. The vaccines provide long-term protection against COVID-19 without the sickness that comes from infection. Therefore, the immune reaction that vaccination elicits is different from that stimulated by infection.

In the context of vaccination, promoting memory immune responses like B cells is the most important for antiviral immunity[7]. Innate responses have very limited memory and their stimulation via vaccination is less relevant.

Furthermore, the limited IFN response following COVID-19 vaccination is not evidence of weakened immunity and has no impact on the immunity against other pathogens or against cancer. Thus, the claim that mRNA vaccines weaken the immune system isn’t supported by scientific evidence.

Finally, the comment by K. Yamamoto is another misinterpretation of a published study. His comment says: “The study showed that immune function among vaccinated individuals 8 months after the administration of two doses of COVID-19 vaccine was lower than that among unvaccinated individuals”. However, the actual observation of this study is that immunity wanes after vaccination. We already know this and it is this waning that justifies the need for a booster shot. In addition, the study reported that the unvaccinated always have a higher incidence of infection compared to vaccinated. In general, studies support the use of vaccine boosters to reduce the risk of hospitalization, even against Omicron[8].

UPDATE (4 August 2022):

The review was updated to include an iteration of the claim by Ben Swann.

UPDATE (29 July 2022):

Dr. Rouers’ comment was received and included after the initial publication. This comment further supports the original verdict and did not modify it. A reference to the letter by Barriere et al. was also added to the review.


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