The Infodemiology Brief —

Cancer myths and anti-mRNA conspiracies abound online

Bird flu has been in the headlines lately, so we’d like to point you to a helpful resource: Our new report describes how online discussions about H5N1 are recycling narratives about COVID-19. Take a read, and feel free to also check out our report on trending measles narratives, other real-time insights, and training resources.   

In other news, a few classic anti-vaccine tactics are dominating online conversations about COVID-19 vaccines. Legitimate studies continue to be misrepresented, and non-peer reviewed data is promoted to advance the false narrative that COVID-19 vaccines are dangerous. Meanwhile, vaccine opponents have continued the anti-vaccine tradition of fearmongering about “scary” vaccine ingredients and new medical technology to put a new spin on the “turbo cancer” and mRNA myths.

Trending narratives from the past month 

A CDC study found no link between COVID-19 vaccines and sudden cardiac deaths in teens and young adults. Vaccine opponents responded with outrage to scientific evidence contradicting the pervasive conspiracy theory that vaccines cause sudden cardiac deaths. Some claimed that the CDC is not a reliable source. Conversely, anti-vaccine groups eagerly promoted a Saudi study finding that 27 percent of study participants who received mRNA COVID-19 vaccines experienced self-reported cardiac complications. That study is being treated as confirmation that COVID-19 vaccines are unsafe despite not comparing cardiac events between vaccinated and unvaccinated populations or controlling for pre-existing cardiovascular disease risk. Read the fact checks here and here.

Fake cancer claims about COVID-19 vaccines continue to circulate

A preprint study using CDC provisional death data claims that cancer deaths began trending up in 2021, insinuating in its conclusion that the rise is linked to COVID-19 vaccines. The study found that cancer deaths spiked in 2020 and continued increasing in 2021 and 2022, which vaccine opponents claim shows an “irrefutable link” between cancer deaths and COVID-19 vaccines. Meanwhile, vaccine opponents have put a new spin on the turbo cancer myth by claiming that an mRNA COVID-19 vaccine component suppresses the immune system and induces cancer growth. Additionally, a conspiracy news article falsely claimed that CDC data proves that COVID-19 vaccines caused a 14,000 percent increase in cancer rates. Read the fact checks here and here.

Conspiracies and calls to ban all mRNA vaccines circulate

As a novel technology, mRNA vaccines have given vaccine opponents a convenient target for endless anti-vaccine conspiracy theories and myths that likely would not stick to more established vaccines. In a video circulating in multiple languages, an oncologist known for promoting false claims about vaccines calls for mRNA technology to be “banished” and for vaccine manufacturers to be held accountable for causing rising cancer rates, despite those increases predating the pandemic. A prominent vaccine conspiracist declared that all mRNA vaccines are “deeply flawed” and dangerous, while a controversial member of the British Parliament called for the government to ban all mRNA vaccines in humans and animals, calling them “the greatest medical scandal in this country.” Read the fact checks here and here.

What you might say in response

The latest CDC data further confirms that COVID-19 vaccines are good for your heart, protecting against COVID-19-associated heart complications.

  • Like previous research, the recent CDC study found no evidence of an increased risk of sudden cardiac death after mRNA COVID-19 vaccination. 
  • COVID-19 increases the risk of heart complications, including heart attacks, for as long as 18 months after infection. Vaccination reduces these risks.
  • Across all age groups, COVID-19 infection is associated with a far higher risk of heart issues than COVID-19 vaccination.

No credible study has demonstrated any link between cancer and COVID-19 vaccines.

  • The preprint circulating among vaccine opponents uses provisional data to assess cancer deaths and draw conclusions that are not supported by the evidence presented. 
  • There is no evidence of a link between COVID-19 vaccines and cancer. mRNA vaccine ingredients are safe and important for enhancing vaccine stability and effectiveness. 
  • Many vaccines have faced similar scrutiny about the safety of their ingredients. Some vaccine ingredients have been the subject of persistent anti-vaccine myths that have caused hesitancy for decades.

mRNA vaccines are a medical technology breakthrough that saved millions and will undoubtedly save millions more.

  • mRNA vaccines are backed by decades of research, and over three years of research and safety monitoring have confirmed their safety.
  • Speculation about mRNA safety vaccines is anti-vaccine fearmongering, no different from myths about vaccines causing autism. These claims are not backed by scientific evidence but rather by anecdotes and noncredible research.
  • Nearly four years of research have shown mRNA COVID-19 vaccines to be extremely safe.

What we’re reading

Studies and trainings

Interested in learning more about how to debunk false claims with patients? Check out the new Infodemiology Training Program. In videos that range from 5 to 10 minutes each, the program introduces health care providers to the basics of infodemiology and provides you with actionable skills to help improve patient care. Get started today. 

Quick response media assets

Below, we've provided a social media asset in English and Spanish. Use these assets on social media to fight false claims and help provide your network with accurate information. Just right-click the asset, or press and hold on mobile, to download.

Proposed caption:
For nearly four years, study after study has confirmed that COVID-19 vaccines are extremely safe. In fact, several recent studies have directly contradicted anti-vaccine myths that falsely link COVID-19 vaccines to cardiac arrest, cancer, and excess mortality. The evidence is clear—COVID-19 vaccines are safe and the best protection against severe illness and death from COVID-19.

Publicación propuesta: 
Durante casi cuatro años, estudio tras estudio ha confirmado que las vacunas contra el COVID-19 son extremadamente seguras. De hecho, varios estudios recientes contradicen directamente los mitos antivacuna que falsamente relacionan a las vacunas contra el COVID-19 con los paros cardíacos, el cáncer y la mortalidad excesiva. La evidencia es clara: las vacunas contra el COVID-19 son seguras y la mejor protección contra la enfermedad grave y la muerte por COVID-19.