Vaccines

Anti-vaccine study resurfaces misleading myocarditis claims

This week, a shingles vaccine study drew mixed reactions online and an ongoing hepatitis A outbreak in California fueled anti-vaccine speculation.

Anti-vaccine study resurfaces misleading myocarditis claims

This week, a shingles vaccine study drew mixed reactions online and an ongoing hepatitis A outbreak in California fueled anti-vaccine speculation.

This week, online vaccine conversations focused on three vaccine studies of varying credibility. Several popular vaccine opponents questioned a dubious study about COVID-19 vaccines and myocarditis with ties to an anti-vaccine organization. Meanwhile, a large-scale study that found shingles vaccination reduces the risk of heart attack, stroke, and other cardiovascular events was dismissed by some as a “scam.” Finally, social media users spread conspiracy theories about the hepatitis A outbreak in Los Angeles County.

Insights brought to you by the reporters and science writers of Public Good News (PGN), a nonprofit newsroom dedicated to improving community health.

A dubious new study authored by an anti-vaccine organization claims without evidence that myocarditis linked to mRNA COVID-19 vaccines is more widespread than reported. The study’s authors are well-known anti-vaccine figures who have promoted several conspiracy theories, including that COVID-19 vaccines cause “turbo cancer.” Many online vaccine opponents promoted the study on social media, calling it “the most definitive myocarditis paper.” Some posts claim that the review proves that mRNA vaccines are unsafe. Although the journal claims to be peer-reviewed, it does not appear to be a legitimate academic publication. The editor in chief, who also co-authored the study, is a former physician whose medical credentials were revoked for promoting false claims about COVID-19 and who now sells hoax vaccine detox products. Additionally, the journal is not found in the National Library of Medicine, the Directory of Open Access Journals, or other publication databases. 

A new study of over a million older adults found that shingles vaccination was associated with a 23 percent reduction in the risk of cardiovascular events, like heart attack and stroke, for up to eight years after vaccination. This follows four studies in the last two years showing that shingles vaccination is linked to a decreased risk of dementia, including Alzheimer’s disease. The study received widespread media coverage and attention online. Some social media users dismissed the research as a “scam”, claiming without evidence that shingles vaccines are dangerous and that this is a plot to trick people into getting vaccinated. Other commenters called all vaccines poisons and alleged that mRNA vaccines are killing people. One post suggested that the study is a way to promote “new” vaccines because no one wants the “coronavirus jab,” despite the fact that the shingles vaccine in the study has been in use since 2006.

On May 5, the Los Angeles County Department of Public Health declared a hepatitis A outbreak. The number of reported cases tripled from 2023 to 2024, and the 29 cases reported in the first three months of 2025 is twice the number reported during the same period last year. Notably, most of the cases reported this year were in people without known risk factors for hepatitis A infection, such as international travel and experiencing homelessness. Health officials encouraged residents to check their vaccination status and wash their hands regularly. Many social media users shared information about the virus and tips to stay safe and promoted hepatitis B vaccination. Others downplayed the outbreak, blamed migrant and homeless populations, and accused health officials and the media of fearmongering. Several commenters claimed without evidence that vaccines caused the outbreak, that the outbreak is a plot to make people get vaccinated, and speculated that either COVID-19 or COVID-19 vaccines have weakened people’s immune systems, making them more susceptible to disease.

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Recommendations brought to you by the health communication experts behind Infodemiology.com.

Each week the Infodemiology.com team will provide talking points and supporting messages in response to some of the trending narratives outlined above. Health care providers can use this messaging when discussing vaccines online, talking to patients, or engaging with communities.

COVID-19 vaccination reduces the risk of heart complications from COVID-19 infection.

Shingles vaccination protects against infection and may also protect your heart and brain as you age.

  • A recent study found that shingles vaccination may reduce the risk of cardiovascular issues like heart attack and stroke. Previous research suggests that the vaccine also reduces dementia risk in older adults. 
  • Shingles is a painful rash caused by the reactivation of the virus that causes chickenpox, which can remain inactive in the body for decades after infection.
  • Older adults and immunocompromised people are most at risk of developing shingles. Many shingles patients experience serious complications, like nerve damage.
  • Doctors recommend that people over 50 and other high-risk adults get two doses of the shingles vaccine, which is up to 97 percent effective for older adults and up to 91 percent effective for immunocompromised adults.
  • The shingles vaccine has been rigorously tested for safety, and serious side effects are extremely rare.

Hepatitis A is a potentially serious viral infection that can be prevented by vaccination.

  • Hepatitis A is a liver infection that spreads through food and water that are contaminated with the virus. 
  • Although certain populations are at higher risk, anyone can contract the disease. 
  • Vaccination is the best protection against hepatitis A and is recommended for all children over age 1 as well as for people at high risk of exposure.


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