Did COVID vaccines cause Sen. Murphy’s stroke?

When well-known people get sick, it is common for anti-vaxxers to look to vaccines. This week, Senator Chris Murphy had a stroke, and Peter McCullough is blaming COVID vaccines.

• COVID illness can raise the risk of strokes, blood clots, and heart attacks.
• Vaccines help lower these COVID-related risks.
• Strokes are becoming more common in younger adults. Checking blood pressure and managing health conditions can help lower risk.

COVID itself can raise the risk of strokes, blood clots, and heart attacks. COVID vaccines can help lower these risks.

More not-so-old people are having strokes, partly because conditions like high blood pressure and diabetes are becoming more common. High blood pressure often has no warning signs, so checking it and working with a doctor can help lower stroke risk. But strokes can also happen in people without these common risks because of inherited conditions or blood clotting problems.

A 2024 study looked at more than 12.7 million older adults and about 78,600 adults with severe kidney disease. People who received the updated booster had about half the risk of COVID-related strokes, blood clots, and heart attacks compared with people who had only received the original vaccines. The risk was 47% lower in the older group and 51% lower in the kidney disease group.

Some people may confuse myocarditis with other heart conditions. Myocarditis is swelling in the heart muscle. It is a rare side effect of mRNA COVID vaccines, seen most often in teen boys and young men. Most patients’ symptoms improve with treatment and rest, often before they leave the hospital. A blood clot is a clump of blood that can block a blood vessel. If a clot blocks blood flow to part of the brain, it cuts off the oxygen that brain cells need. This can cause a stroke. 

Concerns about a rare type of blood clot were linked to a different kind of COVID vaccine, such as Johnson & Johnson and AstraZeneca. These were not mRNA vaccines. A large study of older veterans found only a very small increase in blood clot risk after vaccination of about one or two extra cases per million people.