Sudden arrhythmic death syndrome, seasonal stroke risk concerns long predate the COVID-19 pandemic

The COVID-19 pandemic ushered in an era of significant change, medical and social, for people worldwide. But not everything is new — despite what some social media posts claims. 

"None of these things existed before the plandemic started," reads the text in a video in which a woman claims fact-checkers and sudden arrhythmic death syndrome, or SADS, are new since the pandemic started in 2020. ("Plandemic" is the title of a video that made many false claims about COVID-19 and spread widely online.)  

She also suggests, without evidence, that COVID-19 vaccines cause the syndrome. 

"Oh and their new claims that ‘stroke season’ is an actual thing that happens after the flu season is complete b-------- too," the Instagram post’s caption says.

This post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Meta, which owns Facebook and Instagram.)

Fact-checkers are not new as of the pandemic. PolitiFact started in 2007 and won a Pulitzer Prize in 2009. FactCheck.org debuted in 2003. And sudden arrhythmic death syndrome and "stroke season" weren’t new in 2020.

The British Heart Foundation describes sudden arrhythmic death syndrome as sudden, unexpected death from a cardiac arrest in which the cause is unknown. It usually happens when an abnormal heart rhythm goes untreated, the foundation says. 

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The syndrome has been studied for decades, and research about it has appeared in journals including Frontiers in Physiology in 2013 and Heart in 2007. In 1988, the Centers for Disease Control and Prevention reported on cases of "sudden unexplained death syndrome" among southeast Asian refugees.  

The SADS Foundation in the United States, based in Salt Lake City, was established in 1991 — nearly 30 years before the COVID-19 pandemic started. Warning signs of the syndrome include a family history of unexpected, unexplained death before age 40, fainting or seizure during exercise or excitement, and consistent or unusual chest pain or shortness of breath during exercise. 

The SADS Foundation has encouraged patients to get vaccinated against COVID-19.

The so-called stroke season has also been around for decades. In 1986, the Los Angeles Times published a headline that said, "Study identifies February-April as stroke season." The story

reported that researchers had found that strokes caused by arteries blocked by blood clots or fat occurred most often in those months.. 

More recently, the American Heart Association warned in October 2020 — before the first COVID-19 vaccines were available — that influenza and COVID-19 can increase the risk of stroke, noting it "has long recommended the flu vaccine to protect against cardiovascular disease complications." 

We rate claims that sudden unexplained death syndrome and stroke season are new as of the COVID-19 pandemic False.