# Why comparing blood clot risks from COVID-19 vaccines and birth control pills doesn’t work

Among the most popular comparisons has been the heightened risk of clots that women taking hormonal birth control pills face. And this, in turn, has led some people to question how much the medical community cares about women. The most common complaint: that the J&J jab was paused over a one in a million risk of severe blood clots for the general population, yet women have been encouraged to use oral contraceptives for decades even though 1 in 1,000 develop blood clots — which, it should be noted, is still rare.  

But women’s health experts told MarketWatch that this isn’t a fair comparison for a couple of reasons. First, we’re talking about different types of clots here. 

Dr. Jen Villavicencio, a fellow with the American College of Obstetricians and Gynecologists (ACOG), told MarketWatch in a statement that it is “not appropriate” to compare the risk of clotting associated with the Johnson & Johnson COVID vaccine with the risk of clotting among some hormonal birth control methods. “The clotting syndrome that is currently being investigated by the FDA and the CDC is likely different from the type of blood clotting experienced with birth control,” she said.

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Related: ‘The more we talk about it, the more we’re validating the symptoms’: What we know about COVID vaccine side effects in women

Indeed, government health officials are investigating a type of blood clot called a cerebral venous sinus thrombosis (CVST) among the J&J recipients. These clots formed in the draining veins of the brain, combined with a low platelet count, essentially causing a stroke. Hormonal birth control pills, on the other hand, raise the risk of blood clots in the leg that can break off and travel to the lung, causing a pulmonary embolism that blocks blood flow to part of the lung. The latter clots can be treated with anticoagulants, while the J&J clots cannot. 

What’s more, there are many different personal factors that can raise or reduce the risk of developing a blood clot, such as: a family history of clots; high blood pressure; obesity; pregnancy; recent surgery; or recently suffering a fracture. 

“Each one of us has different risk factors for the same medical intervention, whether it’s the Johnson & Johnson vaccine or whether it’s taking a birth control pill,” Dr. Gloria Bachmann, an OB-GYN and director of the Women’s Health Institute at Rutgers, told MarketWatch. “And there are benefits for both, and there are risks for both, and that’s where one has to evaluate the risk of this intervention, and what would be the risks of getting COVID.” 

Plus, women on the pill are made aware of the risks beforehand, notes Dr. Arthur Caplan, director of NYU Langone’s Division of Medical Ethics. “Some women have suggested maybe people are indifferent to women’s health. I don’t see it that way,” he said. “Women I’ve known on birth control pills are well aware of the risk of clots. People assume the risk, and then decide they’re gonna do it.” 

So while it may be helpful to get people to stop panicking about the J&J pause, or reports of rare blood clots among AstraZeneca
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vaccine recipients, by showing just how many other medications and personal behaviors could be more likely to cause clots, directly comparing the rate of blood clots from birth control with the rate among recipients of COVID vaccines doesn’t really work. “Plus, different birth control pills have different amounts of estrogen and progesterone, and carry different risks of blood clots, so it’s not as simple as making a global statement,” said Bachmann.

Related: The expectation of perfection: Risk of blood clot from Johnson & Johnson COVID-19 vaccine is 0.00009%

But it does resurface the important subject of what’s considered an acceptable risk in medicine — or in anything, really — and the risk-benefit analysis each one of us makes when we decide to take a medication to treat an ailment despite the possible side effects. And the science shows that the benefits of getting vaccinated against COVID outweigh the small risk of blood clots for most people. And that is similar to taking hormonal birth control pills. Bachmann notes that women on birth control enjoy a reduced risk of ovarian cancer, fewer anemia problems, more regular periods, as well as the prevention of unwanted pregnancies. (Pregnancy actually poses an even greater risk of blood clots than birth control pills, she added.)

In the case of COVID-19, the virus has infected more than 31.5 million Americans and killed more 565,695. Health officials are investigating six cases of severe blood clotting, all women, who received the J&J vaccine, including one who died.

What’s more, some 30% of COVID-19 survivors have reported persistent symptoms like fatigue, brain fog and difficulty breathing still plaguing them nine months later. Plus, a new study from researchers at Oxford University has found that people who contract COVID-19 are at far higher risk of developing blood clots than people who receive COVID vaccines. In fact, the risk of cerebral venous thrombosis after a COVID-19 infection is about 100 times greater than normal, and several times higher than after coronavirus vaccination or after the flu.

Read more: Getting COVID creates far higher risk of rare blood clots than vaccines, Oxford study finds

Meanwhile, 99.992% of fully vaccinated people have avoided getting COVID, CDC data shows.

The bottom line is that the fallout from catching COVID right now far outweighs the small risk of possible side effects from any of the vaccines that have been approved for emergency use authorization in the U.S. Problem is, people aren’t great at “translating risk into action,” as Dr. Andrew Pavia, the George and Esther Gross Presidential Professor at the University of Utah, recently told MarketWatch. Which could explain some conflicting behavior. 

“I had someone come up to me today who said, ‘I won’t take that vaccine because it’s dangerous’ — and they smoke two packs [of cigarettes] a day!” Caplan said. Meanwhile, smoking cigarettes can increase the risk of both developing blood clots and suffering severe COVID-19 illness. 

He’s among the doctors who fear that pausing J&J will increase vaccine hesitancy in the U.S. In fact, a recent poll conducted by The Economist and YouGov found that only 37% of respondents think that J&J’s vaccine is safe after the pause, compared with 52% who believed it was safe before the pause.

“I think the messaging should have been, ‘While we examine a possible association [with blood clots] that is serious but rare, keep vaccinating,’” he said. “I wouldn’t stop vaccinating myself or anybody in my family because of this possible association. I would not pull away from the Johnson & Johnson vaccine due to a less than one in a million risk of death.” 

“The biggest risk at the moment is the COVID virus, not the COVID vaccine,” Caplan added.