Skeptics misuse studies to discredit vaccines

Several studies circulating online this week are fueling false claims about the effectiveness and safety of flu and COVID-19 vaccines.

This week, vaccine opponents misrepresented three studies to claim that COVID-19 and flu vaccines are ineffective or unsafe. A non-peer-reviewed Cleveland Clinic study is being used to claim that flu shots increase vulnerability to the flu. Meanwhile, vaccine opponents are circulating a meta-analysis they claim “proves” COVID-19 vaccines cause heart attacks and strokes, contradicting the study’s authors. Finally, a U.S. senator who has repeatedly promoted anti-vaccine claims accused the CDC of covering up data on COVID-19 vaccine safety during pregnancy, a claim that was disproven four years ago.

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What’s trending in vaccine conversation:

A preprint Cleveland Clinic study found that health care workers who received the 2024-2025 trivalent flu vaccine were more likely to test positive for the flu than unvaccinated health care workers. Vaccine opponents shared the study, claiming it proves the flu vaccine is ineffective and harmful. The study has not yet been peer reviewed (vetted by other experts). A popular social media post proclaimed, “Get the shot get the disease!” Other posts called for flu vaccines to be pulled from the market, declaring them a “failure.”

A March analysis that reviewed data from 15 studies found an increase in cardiovascular risks following COVID-19 vaccination. The authors noted that “the odds of experiencing myocardial infarction [heart attack], stroke, and arrhythmia did not exhibit significant elevation due to the administration of COVID-19 vaccines.” Additionally, the researchers concluded that the “findings support the overall safety of the COVID-19 vaccine concerning cardiovascular complications.” Misleading posts about the study are circulating in multiple languages across several social media platforms. Vaccine opponents are claiming that the study “proves” that COVID-19 vaccines are dangerous and should be withdrawn from the market. Several posts claim without evidence that COVID-19 vaccines are causing a rise in heart attacks and strokes.

A U.S. senator who has repeatedly promoted false claims and conspiracy theories about COVID-19 vaccines alleged, without evidence, that a CDC official hid data about COVID-19 vaccine safety during pregnancy. According to articles and social media posts sharing the claim, the now-deleted data shows an 82 percent miscarriage rate. Responses to the claim accused the CDC of misleading the public about COVID-19 vaccine safety. The false claim that 82 percent of pregnancies end in miscarriage after COVID-19 vaccination has been circulating online for nearly four years, originating from a gross misrepresentation of a preliminary study published in the New England Journal of Medicine. 

Read the fact checks: 

• Health: Does the Flu Shot Raise Infection Risk? Here’s What a New Study Actually Found 
• UnityPoint Health: Can COVID-19 or COVID-19 Vaccines Cause Heart Damage? 
• CDC: COVID-19 Vaccination for Women Who Are Pregnant or Breastfeeding 

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Talking points for health care providers to use in response to trending narratives

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.

The flu shot is the best way to prevent the flu and avoid severe illness.

• Flu vaccine effectiveness varies year to year. But studies consistently show that vaccination reduces the risk of infection, severe illness, complications like pneumonia and heart attacks, hospitalization, and death from the flu.
• Despite claims to the contrary, no study has found that flu vaccines increase the risk of catching the flu. A recent study found that health care workers who received one type of flu shot were more likely to test positive for the flu. This could be because workers who have a higher risk of flu exposure are more likely to be vaccinated, because vaccinated people are more likely to get tested, or because the flu vaccine in this study was less effective at preventing infection than hoped.
• The study results can’t be applied to the population at large, especially those who are most at risk from the flu, such as young children and older, pregnant, and immunocompromised adults. 

Getting vaccinated is the best protection against serious heart complications caused by COVID-19.

• Getting COVID-19 is bad for your heart. Vaccines are the best protection. 
• Over three years of research have not identified any link between mRNA COVID-19 vaccines and heart attacks or stroke. On the contrary, COVID-19 vaccination decreases the risk of COVID-19-related heart attack or stroke, which can persist for up to three years after infection.  
• Some vaccine opponents falsely claim that COVID-19 vaccines are harmful based on a new study. But the study’s own authors concluded that the vaccines are safe. 

COVID-19 vaccination is safe during pregnancy. There is no link between vaccines and miscarriage. 

• Dozens of large-scale studies over the last four years have shown that COVID-19 vaccines are safe during pregnancy. Research shows there is no increase in negative pregnancy outcomes, including miscarriage or stillbirth, after COVID-19 vaccination.
• In 2021, vaccine opponents manipulated data from a preliminary study to falsely claim that COVID-19 vaccines increase miscarriage risk. The study actually found no difference in miscarriage rate between vaccinated and unvaccinated women. Four years later, the study is still being misrepresented to spread false claims. 
• The American College of Obstetricians and Gynecologists “strongly recommends” COVID-19 vaccination during pregnancy.

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