U.S. Recommends a "Pause" On the Johnson & Johnson COVID-19 Vaccine Due to Blood Clot Concerns

Renee Cherry
·5 min read

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The Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) are recommending that administration of the Johnson & Johnson COVID-19 vaccine be "paused" despite 6.8 million doses having already been administered in the U.S. to date. The news comes via a joint statement that suggests health care providers discontinue the use of the Johnson & Johnson vaccine until further notice. (Related: Everything You Need to Know About Johnson & Johnson's COVID-19 Vaccine)

This new recommendation is the result of a rare but severe type of blood clot called cerebral venous sinus thrombosis (CVST) being found in some individuals who received the particular vaccine in the U.S., according to the statement. In this case, "rare" means only six reported cases of the post-vaccination blood clot out of those nearly 7 million doses. In each case, the blood clot was seen in combination with thrombocytopenia, aka low levels of blood platelets (cell fragments in your blood that allow your body to form clots to stop or prevent bleeding). So far, the only reported cases of CVST and thrombocytopenia following the Johnson & Johnson vaccine have been in women between the ages of 18 and 48, 6 to 13 days after receiving the single-dose vaccine, according to the FDA and CDC.

CVST is a type of rare stroke, according to Johns Hopkins Medicine. (ICYDK, a stroke essentially describes a situation in which "the blood supply to part of your brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients," according to the Mayo Clinic.) CVST occurs when a blood clot forms in the brain's venous sinuses (pockets between the outermost layers of the brain), which prevents blood from draining from the brain. When the blood is unable to drain, a hemorrhage can form, meaning blood can start leaking into the brain tissues. Symptoms of CVST include headache, blurred vision, fainting or loss of consciousness, loss of control of movement, seizures, and coma, according to John Hopkins Medicine. (Related: How Effective Is the COVID-19 Vaccine?)

Given the low number of CVST reports out of all the people who have received the Johnson & Johnson COVID-19 vaccine, you might be wondering if the CDC and FDA's response is an overreaction. The fact that the blood clots and low platelets occurred in combination is what makes these cases so notable, said Peter Marks, M.D., Ph.D., director of FDA Center for Biologics Evaluation and Research, in a media briefing. "It's their occurrence together that makes a pattern and that pattern is very, very similar to what was seen in Europe with another vaccine," he said. It's likely that Dr. Marks is referring to the AstraZeneca vaccine, given the news that multiple countries in Europe briefly suspended their use of the vaccine last month due to reports of blood clotting and low platelets.

Typically, a coagulant drug called heparin is used to treat blood clots, according to the CDC and FDA's joint statement. But heparin can cause a drop in platelet levels, so it can be dangerous when used to treat people who already have a low platelet count, such as in the case of the six women with J & J issues. Pausing use of the vaccine is an effort to "make sure that providers are aware that if they see people who have low blood platelets, or if they see people who have blood clots, they need to inquire about a history of recent vaccination and then act accordingly in the diagnosis and management of those individuals," explained Dr. Marks during the briefing.

It's important to note that just because the CDC and FDA suggest a "pause" doesn't necessarily mean that administration of the Johnson & Johnson vaccine will be completely halted altogether. "We're recommending that the vaccine be paused in terms of its administration," said Dr. Marks during the briefing. "However, if an individual health care provider has a conversation with an individual patient and they determine that the benefit/risk for that individual patient is appropriate, we're not going to stop that provider from administering the vaccine." The benefits will outweigh the risks in "the large majority of cases," he added.

If you're one of the millions of Americans who already received the Johnson and Johnson vaccine, don't panic. "For people who got the vaccine more than a month ago, the risk event is very low at this time," said Anne Schuchat, M.D., principal director of the CDC, also during the media briefing. "For people who recently got the vaccine within the last couple of weeks, they should be aware to look for any symptoms. If you received the vaccine and develop severe headaches, abdominal pain, leg pain, or shortness of breath, you should contact your health care provider and seek treatment." (Related: Can You Work Out After Getting the COVID-19 Vaccine?)

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.