Why You Shouldn't Worry About Blood Clots & The Covid Vaccine

News that the Johnson & Johnson Covid-19 vaccine roll-out has been placed on hold due to concerns over six cases of a rare blood clot condition is causing some anxiety, and government agencies are working to quickly discover if there are any proven links to be made. New details are likely to emerge in the coming days, but there are some important facts about blood clots and Covid vaccines to keep in mind: First and foremost, these occurrences have been extremely rare, while the risk of contracting Covid continues to be a real and present danger.

On Tuesday, the U.S. Centers for Disease Control and Prevention (CDC), along with the U.S. Food & Drug Administration (FDA), shared a recommendation to pause distribution of the J&J Covid-19 vaccine while they conduct research into the documented cases of a half-dozen women between the ages of 18 and 48 who got that vaccine and also experienced blood clots in the days after. While over 7 million of the one-dose J&J vaccines have been given out in the United States, doctors and experts are looking into these very rare instances out of an “abundance of caution,” which J&J also expressed in their statement on the matter.

What exactly is the concern about blood clots and the J&J vaccine?

On Tuesday, the CDC and FDA shared details on the ongoing review process. The instances under review involve a small number of women who evidently presented with cerebral venous sinus thrombosis (CVST, the kind of clot in question) and a low count of platelets, known as thrombocytopenia.

Experts stress that this is important because such a dual diagnosis would require a specialized treatment, and not a more common blood-clot treatment like heparin, which works to thin your body’s blood. A blood thinner, explained the experts, would actually make the condition worse. A big reason for the pause is to make sure that medical providers understand how to treat patients with this condition, however rare it may be.

And rare it is. As Quartz explained, “The effective risk of blood clots associated with the J&J vaccine is extremely low. Even if all the cases emerged so far were confirmed, that would be only 0.00009% of people who receive the shot — or 9 in 10 million.” And, the outlet points out, “Covid-19 causes blood clots in about 20% of its severe cases — nearly 100% of which are avoided thanks to the J&J vaccine.”

How does this compare with the concerns about the AstraZeneca vaccine?

This may not be the first time you’ve heard about blood clots and Covid-19 vaccinations; use of the AstraZeneca vaccine was paused in some countries in Europe when a few patients reportedly experienced blood-clot issues. Though its use was resumed in some countries, recent reports say others may halt it again. Again, experts cautioned that the risk of blood clots was very low. “European regulators have stressed that the AstraZeneca risk appears to be far lower than the possibility of developing clots from birth control pills, which typically cause clots in about 4 of every 10,000 women who use them for a year,” reported the Chicago Tribune.

Both the J&J and AstraZeneca vaccines use a different kind of technology that the two-shot Moderna and Pfizer vaccines “some experts suspect the key technology used to make the Johnson & Johnson vaccine — as well as the AstraZeneca vaccine — may play a role in the blood clots,” says CNN.

Because of the AstraZeneca vaccine, the initial roll-out of the Johnson & Johnson vaccine was also paused in Europe. But on April 20, J&J said the distribution of the vaccine would resume after the European Union’s drug regulators declared that a warning should be added to the Johnson & Johnson shots indicating a possible risk of blood clots, but also noting that the benefits of the shot outweigh the minute risk. “The rare clots were ‘very similar,’ the agency added, to those associated with the AstraZeneca vaccine, for which the agency made a similar recommendation,” The New York Times reported. “The agency said it had come out with its recommendations ahead of U.S. regulators doing so because it had built some confidence in how to respond in having spent much time reviewing similar cases that arose with the AstraZeneca vaccine.”

What do I need to know if I’ve gotten the J&J vaccine? What are the symptoms of blood clots?

Health care providers, the CDC, and the FDA say recipients of all the Covid vaccines might experience flu-like symptoms in the days following their doses (think general fatigue or chills, or even headache). This is perfectly normal. However, if serious headaches, abdominal or leg pain, or breathing issues occur after your Johnson & Johnson vaccine — especially within one to three weeks — seek medical help immediately, and let them know that you have been vaccinated.

If more than a month has gone by since your dose, there’s even less cause for worry, said Dr. Anne Schuchat, M.D., principal deputy director of the CDC.

The bottom line on Covid vaccines and this blood clot scare?

Asking questions is a good thing — talk to your health care provider about your vaccine options. Representatives from the CDC and FDA said that with this small number of reports, they’re unable to make definitive conclusions about pre-existing conditions. But they did repeatedly stress the rarity of these cases and the ongoing need for the public to get vaccinated in the face of a “worsening global pandemic.”

In their joint call, CDC and FDA members stressed that people scheduled to receive the other two available shots should move forward with those plans. You can also stay up-to-date with this news via the CDC’s website, and find more information from Romper about Covid and its evolving treatments.