Mild COVID Infections Double Heart Attack and Stroke Risk for Years After Recovery as New XFG Variant Spreads
The Silent Toll: COVID’s Lingering Threat to Hearts and Brains
As XFG variant spreads, experts warn repeat infections could raise long-term risks for heart and brain health
The packed emergency rooms are gone. Temporary field hospitals have long been dismantled. Yet five years into the pandemic, one unsettling question hangs in the air: what hidden cost are we still paying for those COVID-19 infections we thought we left behind?
Researchers say the answer is sobering. Even people who barely felt sick during their bout with COVID face sharply higher odds of heart attacks and strokes years later. Each new infection seems to add more risk, stacking damage like layers of scar tissue.
Now, as the new XFG variant sweeps across the globe, health officials are coming to terms with a hard truth: the virus’s legacy may claim more lives through heart disease and strokes than it ever did in its acute phase.
The Hidden Epidemic
The numbers don’t lie. Data from the UK Biobank shows people who caught COVID—hospitalized or not—had nearly double the risk of major heart or brain events over three years compared with those who never tested positive. And it wasn’t just the elderly or people with underlying problems. Young, healthy adults who thought they had shrugged off the illness showed the same pattern.
A recent JAMA Health Forum analysis drove the point home: recovery doesn’t mean the body goes back to baseline. The virus leaves behind vascular damage that lingers, creating fertile ground for clots, blocked arteries, strokes, and abnormal heart rhythms.
Think of it this way: the virus attacks the endothelium, the delicate lining inside blood vessels. Once inflamed, those vessels don’t heal quickly. Instead, they stay unstable, making the circulatory system more fragile for months, sometimes years.
The Cumulative Burden
The picture looks even darker with repeat infections. A Washington University study found people who caught COVID more than once were three times more likely to develop heart problems and nearly twice as likely to suffer brain issues compared with those infected only once.
Every new infection, researchers say, acts like another blow to the cardiovascular system. Inflammation surges again, clots form more easily, and existing arterial plaques grow more unstable. Over time, the risks pile up.
Other studies—from Sweden’s nationwide cohorts to U.S. hospitals—echo the same finding: cardiovascular and cerebrovascular complications keep surfacing long after recovery, with hospitalized patients facing the steepest risks.
Enter XFG
Against this backdrop, the rise of the XFG variant, nicknamed “Stratus,” has triggered fresh concern. The World Health Organization is watching it closely. While it doesn’t seem to cause more severe illness than earlier strains, it spreads quickly thanks to its ability to dodge immunity, even in vaccinated populations.
The danger lies not in each individual infection but in the sheer number of infections. More cases mean more opportunities for heart attacks, strokes, and long-term vascular harm.
As one expert put it bluntly: even if the risk per infection stays the same, multiplying infections could swell the overall toll to a level far greater than what we tracked during the pandemic’s deadly first years.
The Invisible Timeline
One of the most insidious features of this risk is its delay. A person infected today might not suffer a heart attack or stroke for months—or even years. By the time doctors see the connection, countless patients may already have endured preventable tragedies.
Signals to watch for include unusual spikes in sudden cardiac deaths, higher-than-expected rates of heart attacks and strokes, or lab evidence showing that XFG is especially disruptive to blood vessels. But waiting for such proof could mean missing the chance to intervene early.
Who’s Most at Risk?
Certain groups clearly face higher stakes. People with heart disease, diabetes, obesity, or high blood pressure show the steepest climb in complications. A 2025 review confirmed that patients with coronary artery disease who had severe COVID fared much worse long term.
Still, the danger doesn’t stop there. Even those who felt fine after a “mild” case face doubled risk. In other words, no one gets a free pass.
The Policy Gap
These findings raise uncomfortable policy questions. Should governments double down on preventing reinfections? Would antivirals given early blunt long-term damage? Should doctors begin routine heart checks for patients recovering from COVID?
For now, most patients walk out of recovery with little to no follow-up. Few get screened for cardiovascular issues or warned about their higher risk. Yet the wave of delayed heart attacks and strokes could overwhelm health systems already stretched thin.
A Call for Vigilance
Public health leaders stress awareness, not alarm. XFG isn’t a doomsday variant, but it does underline the need for continued vigilance. Vaccination and boosters aren’t just about avoiding the flu-like misery of COVID—they may help shield against long-term cardiovascular fallout too.
For individuals, the advice is simple: don’t shrug off infections. Manage blood pressure and cholesterol. Know the warning signs of heart attack and stroke, and seek help fast if they appear.
For society, the challenge is broader. The pandemic’s story didn’t end when hospitals emptied. Its true cost may play out in cardiology clinics and emergency rooms for decades.
The Unfinished Story
Five years on, COVID continues to rewrite the rules of modern medicine. The virus keeps evolving, slipping past immunity and setting new traps for the unwary. With every new infection, the clock ticks forward on consequences we’ve only begun to measure.
The question isn’t whether COVID can damage hearts and brains—it can, and it does. The question is how many lives it will alter in the years to come, and whether we’ll be ready when the bill arrives.