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Video Falsely Claims 850 People Died of Myocarditis in Mexico

This article is available in both English and Español

SciCheck Digest

Cases of myocarditis have been reported following mRNA COVID-19 vaccination, but they are rare and usually mild. Yet, a viral video distorts news reports to falsely claim 850 people died in Monterrey, Mexico, in June due to myocarditis. The figure comes from a false report of heat-related deaths.

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Multiple studies and safety monitoring systems have shown that the mRNA COVID-19 vaccines are remarkably safe. Myocarditis, or inflammation of the heart muscle, has been identified as a serious side effect of the vaccines, mostly in young males after a second dose. But according to the Centers for Disease Control and Prevention, cases are rare and most of them resolve quickly. Myocarditis can also be triggered by a COVID-19 infection. 

Yet, the rare risk of vaccine-induced myocarditis has been mischaracterized over and over to spread fear and falsely claim mRNA COVID-19 vaccines are dangerous. 

A recent example is a widely shared video of a woman falsely claiming that in Monterrey, the capital of the northeastern state of Nuevo León in Mexico, 850 people died due to myocarditis in a two-week span. The woman does not directly link the deaths to COVID-19 vaccination but says doctors “are coming out” because the government and the media are “lying” by saying the deaths were caused by a heat wave and “because people already woke up, and they’re not going to be pushed around like they did during the pandemic.” 

“These doctors have grown some guts, and they’re saying that these 850 deaths in these past two weeks in Monterrey are due to myocarditis, straight up myocarditis,” the woman says. The comments on the original TikTok video, published by an account that has spread misinformation about COVID-19, show that people got the reference. “It’s the Jab,” one says. “Shots shots shots shots,” another reads. A more viral version of the video, republished on Facebook, adds crown emojis to the screen, a reference to the coronavirus. 

But it’s not true that 850 people died in two weeks in Monterrey due to myocarditis or from heat-related illnesses. Sonia Gómez, a spokesperson for the Health Ministry of Nuevo León, told the Associated Press the claim was false. We reached out to the ministry, but we did not hear back.

The video distorts statements made separately, but on the same day, by two state officials. First, Luis Enrique Orozco Suárez, a prosecutor from the attorney general’s office of Nuevo León, said on June 27 that the Forensic Medical Service was out of capacity after receiving between two and three times the average number of bodies during a heat wave that affected the state that month. He said most of the deaths were caused by acute myocardial infarction, or heart attacks, but added that some individuals presented with several diseases. When asked if the heart attacks were due to the heat wave, Orozco said it was up to the health department to determine that.  

A myocardial infarction is not the same as myocarditis. A heart attack happens when blood flow in the heart is blocked or greatly reduced, usually because of a blockage in one or more arteries. This can cause irreversible damage to the heart muscle due to a lack of oxygen. Myocarditis is inflammation of the heart muscle, which can affect its capability to pump blood. Orozco didn’t say anything about myocarditis.

That same day, a state official from the vital records office of Nuevo León falsely stated 850 people died of heat stroke in an interview with Telediario Radio

“Sorry, how many?” the interviewer asks in Spanish, in disbelief. “From two weeks to now, there are 850 deaths due to heat stroke,” said the official, named Miguel Gallardo, according to news reports. Gallardo added that the cause of death written in the death certificates was heat stroke. 

State authorities immediately dismissed the information.

“The State Government categorically denies the alleged number of deaths due to the heat wave reported by the public servant Miguel Gallardo,” a state press release reads. 

According to statements given by the state health secretary, Alma Rosa Marroquín Escamilla, the next day, there were 36 deaths associated with the heat wave in Nuevo León from June 14 to 27. Marroquín told the media another 651 people needed medical care due to heat stroke and dehydration. According to a report published on June 19 by El Universal, the heat wave was one of the worst in decades, with temperatures reaching between 104 and 113 degrees Fahrenheit for 10 days as of the day of publication. 

The viral video shows several news clips in Spanish with the words “The GOVERNMENT IS LYING!!” on the screen. But those news stories recount this case of miscommunication — Gallardo incorrectly claiming 850 people died of heat stroke, state and federal officials denying that information, and the forensic service saying there had been many deaths due to heart attacks. 

The video twists those events to make the false claim that 850 people died from myocarditis. 

Editor’s note: SciCheck’s articles providing accurate health information and correcting health misinformation are made possible by a grant from the Robert Wood Johnson Foundation. The foundation has no control over FactCheck.org’s editorial decisions, and the views expressed in our articles do not necessarily reflect the views of the foundation.


Selected Adverse Events Reported after COVID-19 Vaccination. CDC. Updated 13 July 2023. Accessed 8 Sep 2023. 

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