The Johnson & Johnson COVID-19 Vaccine Pause: What You Need to Know


Dr. Todd Ellerin

Todd Ellerin, MD, Director of Infectious Disease

In a joint statement, the Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) recommended a pause in distribution of the one-shot Johnson & Johnson COVID-19 vaccine.

The regulators did this to investigate reports of rare but serious blood clots that may be induced by the vaccine—particularly in young women.

For patients who’ve recently received the Johnson & Johnson vaccine, the headlines are no doubt alarming. But this pause is a good thing.

It reminds us that safety is the top priority when it comes to COVID-19 vaccines.

We need to give our regulators time to step in and look at the data so we can decide if the benefits of certain vaccines outweigh the risks—or if we need to stop its use in certain populations.

Here are some answers to questions you may have about the pause in distribution of the Johnson & Johnson vaccine.

Why did the FDA and CDC recommend a pause for the Johnson & Johnson vaccine?

According to the joint statement, there have been six cases of a rare but life-threatening blood clot, called a cerebral venous sinus thrombosis (CVST). The clots were seen in combination with low levels of blood platelets (thrombocytopenia) in these patients.

The technical team for this syndrome is vaccine-induced Thrombotic Thrombocytopenia.

The FDA and the CDC add, “All six cases occurred among women between the ages of 18 and 48, and symptoms occurred 6 to 13 days after vaccination.”

How common are cerebral venous sinus thrombosis (CVST) blood clots?

These types of blood clots are so rare, it’s hard to get an accurate measure of how common they are.

Research estimates there are between three and four cases per million people each year in adults, with most cases appearing in women in their thirties, some of whom are on birth control pills.

Given the issues with the Johnson & Johnson and AstraZeneca vaccines, is there a critical problem with the viral vector COVID-19 vaccines?

There are two types of COVID-19 vaccines on the U.S. market: The messenger RNA vaccines (Pfizer and Moderna) and viral vector vaccines (Johnson & Johnson and the not-yet-approved-in-the-U.S. AstraZeneca, which has made headlines due to blood clot risks).

To date, blood clots in the brain or other unusual sites have been a rare but serious side effect of the viral vector vaccines. We have not seen Thrombotic Thrombocytopenia reported in patients who received the mRNA vaccines.

The New England Journal of Medicine published research from Europe about the AstraZeneca vaccine, which suggests the viral vector vaccines may trigger an antibody response in some patients that can put them at risk of serious clots.

The European Medicines Agency has investigated this issue, have concluded that the AstraZeneca vaccine can rarely cause vaccine-induced Thrombotic Thrombocytopenia—but feels overall benefits outweigh the risks and countries should make their own decisions about who can get this vaccine.

To date, four European countries have stopped using the AstraZeneca vaccine altogether, while many others (including Germany, France, and Spain) have put age restrictions on it.

We may see the FDA and CDC make a similar recommendation here in the U.S. when it comes to Johnson & Johnson.

Why aren’t regulators discontinuing use of the Johnson & Johnson vaccine outright?

As of April 12, nearly seven million doses of the Johnson & Johnson vaccine have been distributed in the United States. The six cases of blood clots, while serious, do not mean we write off an extremely effective vaccine entirely.

While the Johnson & Johnson vaccine—along with the Moderna and Pfizer vaccines—went through rigorous clinical trials, expanding use to the wider population always tells us more about the efficacy and risks.

Again, it’s possible the regulators will extend the pause on the J&J vaccine, or will issue further recommendations about who can safely get the vaccine.

When will the CDC and FDA give an all-clear?

The CDC will hold a meeting of the Advisory Committee on Immunization Practices (ACIP) to review the six cases and assess their potential significance. The FDA will then review that analysis as part of its investigation.

The investigators will examine whether there is proof that the Johnson & Johnson viral vector vaccine caused Thrombotic Thrombocytopenia in these six women, or if something else is to blame.

U.S. agencies will also take a look at what’s going on with the AstraZeneca viral vector vaccine in Europe.

Examining all of this data takes time. I’m glad the FDA and CDC are being transparent about their processes and hope they will continue to update the public as they move through the process. It could take days—or it could take weeks.

Luckily, we still have Pfizer and Moderna vaccines being produced, so keep any vaccination appointments you may have!

I got the Johnson & Johnson vaccine recently. What should I do?

First of all, don’t panic.

If it’s been less than three weeks since you received your J&J vaccine, watch for these symptoms:

  • Severe, persistent headache
  • Severe, persistent abdominal pain
  • Severe, persistent leg pain
  • Shortness of breath
  • New neurologic symptoms, such as trouble speaking, confusion, or visual disturbances 
  • New or unusually easy bruising

If you experience any of the above, call your primary care provider.

Even if regulators say the J&J vaccine is safe, I won’t take it if I’m offered it down the road.

Vaccinating as many people as possible is key to stopping the proliferation of dangerous COVID-19 variants. But it’s critical that we do so with safe, effective vaccines.

Trust is at a premium. Healthcare providers have worked nonstop to build confidence in the safety of these vaccines, and fight misinformation that goes viral online.

It’s possible the FDA and CDC will come back after their review and say the vaccine is safe only for certain populations. I encourage everyone to keep an eye on accurate news sources, such as the CDC’s website, for updates on which vaccines are safest for you.

By taking a short break to review the data, the CDC and FDA will glean more information. This allows healthcare providers to make more informed recommendations about the COVID-19 vaccine.

Learn more about COVID-19.