Modified RNA in COVID-19 vaccines aren’t linked to cancer development – Health Feedback

CLAIM

A review has found that COVID-19 mRNA vaccines could aid cancer development

DETAILS

Misrepresents source: The claim originates from the conclusion of a literature review based on a study by Sittplangkoon and colleagues. However, this review didnt accurately represent the studys findings. Contrary to the claim, the study didnt show that modified mRNA like those used in COVID-19 vaccines enhanced cancer development. Inadequate support: The claim suggested that new results established a link between COVID-19 vaccines and cancer development. However, the scientific publication used to support that claim is a literature review. This form of publication summarizes existing knowledge but doesn't provide any new results.

KEY TAKE AWAY

The mRNA COVID-19 vaccines contain RNAs with chemical modifications that increase their stability and improve their ability to induce a potent immune response. Some results suggest that such chemical modifications make mRNA-based anti-cancer vaccines less effective. However, it doesnt mean that COVID-19 vaccines increase the risk of cancer. Theres no evidence that COVID-19 vaccination increases the risk of cancer.

However, the organization Americas Frontline Doctors, known for spreading COVID-19 disinformation, continues to push this narrative. More recently, it claimed that an April 2024 scientific publication by Rubio-Casillas et al. found that COVID-19 mRNA vaccines could aid cancer development[1].

The website The HighWire, which has previously published false claims about COVID-19 and vaccines, also wrote that the scientific paper showed that mRNA vaccines could aid cancer development. The HighWire cited Peter McCullough, a cardiologist known for spreading misinformation about COVID-19 vaccines. McCullough said that not only could the COVID-19 mRNA jabs aid cancer development, but they could actually cause and worsen cancer, not make it better.

However, this claim is unsubstantiated. The scientific publication presented as evidence for this claim doesnt contain new results that support the claim and it misinterprets results from another study.

To begin with, this paper by Rubio-Casillas et al. isnt a study. It doesnt contain new experimental or clinical results. Instead, the authors conducted a review of already-existing literature.

This is a crucial difference between studies and literature reviews. A study formulates a hypothesis and tests it by conducting experiments, data analysis, and trials, thereby producing new knowledge.

By contrast, a literature review summarizes what is already known and provides a critical analysis of results and competing hypotheses. This can lead to formulating new hypotheses and identifying new avenues of research, but it doesnt in itself demonstrate anything new. New hypotheses that may arise still would need to be confirmed experimentally and clinically. Thus, the claim that this paper has found a link between COVID-19 vaccines and cancer isnt correct, because it didnt test that hypothesis with experiments and clinical trials.

The main claim of Rubio-Casillas et al. was that the mRNA used in COVID-19 mRNA vaccines contained chemical modifications that allegedly stimulated cancer growth and metastasis, thus suggesting that COVID-19 mRNA vaccines could aid cancer development.

This refers to modified nucleotidesthe building blocks of RNAs and DNAsused in the COVID-19 mRNA vaccines. More specifically, instead of the nucleotide uridine, the vaccine mRNA contains N1-methyl-pseudouridine.

Unmodified RNAsusing normal uridinetrigger an inflammatory response and are rapidly degraded upon entering a cell. By contrast, modified RNAs using N1-methyl-pseudouridine are able to evade the cells RNA detection system and dont trigger inflammation[2]. Vaccines using modified RNA are able to induce greater antigen production, are better tolerated due to a lower inflammation, and induce a stronger immune memory[2]. It was the discovery of modified RNAs immunomodulating potential that won Katalin Karik and Drew Weissman the Nobel Prize in Physiology or Medicine in 2023.

Rubio-Casillas et al. heavily relied on a study by Sittplangkoon et al. to support their claim that N1-methyl-pseudouridine, although useful for vaccine effectiveness, could also favor the development of cancer[3]. Indeed, Sittplangkoon et al. is the only study cited in the review that directly investigates the effect of uridine modifications in cancer immunity.

Furthermore, Rubio-Casillas et al. claimed in their abstract that evidence is provided[] suggesting that COVID-19 mRNA vaccines could aid cancer development. This sentence refers to the work by Sittplangkoon et al. and has been repeated in several versions of the claim.

However, this is an incorrect interpretation of this study, as we explain below.

Its important to clarify that Sittplangkoon et al. didnt investigate whether COVID-19 vaccines enhance cancer development. In fact, their work focused on anti-cancer vaccines, that is, a vaccine boosting immunity against a specific cancer, the same way that COVID-19 vaccines boosts immunity against the SARS-CoV-2 virus.

To do this, the researchers injected mice with melanoma cells (melanoma is a type of skin cancer) producing the protein ovalbumin (a protein abundant in egg whites). At the same time, they immunized the mice with a vaccine containing mRNA containing the genetic information to produce that ovalbumin protein. The objective was to train the mices immune systems to recognize and destroy ovalbumin-carrying melanoma tumors, just like the COVID-19 vaccine trains the immune system to recognize and destroy the spike-carrying SARS-CoV-2.

From the start, we can see that Sittplangkoon and colleagues were addressing a completely different scientific question from the one that Rubio-Casillas et al. tried to address. Rubio-Casillas et al. debated whether COVID-19 mRNA vaccines, which contain mRNA for the spike protein to build immunity against a virus, could inadvertently impair our immune defense against naturally-occurring cancers. By contrast, Sittplangkoon et al. asked whether modified and unmodified RNAs could be used in a vaccine targeting a specific, artificially-induced cancer.

Sittplangkoon et al. found that the anti-cancer vaccines that used unmodified RNAs efficiently boosted immunity against the melanoma. By contrast, the vaccines using modified RNAs didnt improve immunity against melanoma compared to unvaccinated, healthy mice (Figure 1).

Figure 1 Effect of anti-cancer vaccines containing either modified or unmodified RNAs on tumor growth. This graph represents melanoma growth in mice that are unvaccinated, or vaccinated with modified or unmodified mRNA. Modified RNA containing N1-methyl-pseudouridine is indicated by 100% m1. Grey line: Mice vaccinated with unmodified RNA. Blue line: mice vaccinated with modified mRNAs. Red, orange and green lines: mice that havent been vaccinated. Source: Sittplangkoon et al[3].

Its important to emphasize that mice vaccinated with modified RNAs didnt fare worse than unvaccinated mice. So, the presence of N1-methyl-pseudouridine didnt hamper the mices immunity against cancer; it just didnt improve anti-cancer immunity.

In summary, the results of Sittplangkoon et al. suggest that anti-cancer vaccines would be more effective if they didnt contain modified RNAs. But they didnt show that the N1-methyl-pseudouridine contained in modified mRNA was detrimental to anti-cancer immunity of our body. In the absence of such a finding, the claim by Rubio-Casillas et al. is unsubstantiated and misrepresents the original study by Sittplangkoon et al. We reached out to the authors of Rubio-Casillas et al. to know if they took into consideration the results from Sittplangkoon et al. that we presented here and will update this review if new information becomes available.

In conclusion, Rubio-Casillas et al. offered no new data to support the claim that COVID-19 vaccines cause cancer or favor cancer development. This claim strongly relies on a study by Sittplangkoon et al. that was unrelated to COVID-19 vaccines and didnt show what Rubio-Casillas et al. claimed it did.

Originally posted here:

Modified RNA in COVID-19 vaccines aren't linked to cancer development - Health Feedback