FDA, CDC recommend a pause in use of Johnson & Johnson's COVID-19 vaccine

The Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) recommended a pause in the use of Johnson & Johnson's COVID-19 vaccine "out of an abundance of caution" on Tuesday.

In a series of tweets Tuesday morning, the FDA said it was recommending a pause after receiving reports that six people developed "rare and severe" blood clots after receiving the vaccine. So far, nearly 7 million Americans have received a dose of the Johnson & Johnson vaccine.

Dr. Peter Marks, the director of the Center for Biologics Evaluation and Research, said during a press conference Tuesday that the clotting events led to the death of one patient and that another patient remains in critical condition.

"CDC will convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to further review these cases and assess their potential significance. FDA will review that analysis as it also investigates these cases," the FDA said in a statement Tuesday.

During Tuesday morning's press conference, acting FDA commissioner Dr. Janet Woodcock said the review would take a matter of days but could extend longer depending on "what we learn." At a White House press briefing later in the day on Tuesday, Dr. Anthony Fauci, President Joe Biden's top medical adviser, said that he thought the pause was "going to be more like days to weeks, rather than weeks to month."

Dr. Anne Schuchat, the principal director of CDC, added that the pause was taking place in order to better prepare the health system in the event more patients experience clotting.

Throughout Tuesday's press conference, officials were clear that the events were extremely rare, and so far had only presented in patients that suffered from thrombocytopenia — low levels of blood platelets — and those who had histories of blood clotting issues.

Schuchat added that anyone who received the Johnson & Johnson vaccine over a month ago likely won't experience the clotting issues moving forward. She also said that anyone who has taken the Johnson & Johnson vaccine within the last month and experienced "severe headaches, abdominal pain or leg pain" should contact their doctor. She noted that pain would be different than the typical aches and pains associated with the flu.

Fauci noted during the White House press briefing Tuesday that headache is the main warning sign for potential clotting issues. He added that people who have recently received the Johnson & Johnson vaccine should "pay attention," but not "get an anxiety reaction" worrying about the issue.

Marks also clarified Tuesday that the FDA's and CDC's decisions were just a "recommendation. It is not a mandate." He added that the government would not stop health providers from administering the vaccine to patients who still want the vaccine and understand the risk.

ABC News reports that in a statement, Johnson & Johnson wrote that safety was the company's top priority and that it met regulatory standards for reporting the adverse effects of its products.

"We are aware that thromboembolic events including those with thrombocytopenia have been reported with COVID-19 vaccines," the company said in its statement. "At present, no clear causal relationship has been established between these rare events and the Janssen COVID-19 vaccine. We continue to work closely with experts and regulators to assess the data and support the open communication of this information to healthcare professionals and the public."

The decision to pause the use of the Johnson & Johnson vaccine — currently the only single-dose vaccine approved for use in the U.S. — comes less than a week before President Joe Biden's target date to ensure all Americans are eligible for a COVID-19 vaccine.

In a statement released Tuesday morning, White House COVID-19 response team coordinator Jeff Zients said that the FDA's decision "will not have a significant impact on our vaccination plan."

"Johnson & Johnson vaccine makes up less than 5 percent of the recorded shots in arms in the United States to date," Zients said in his statement. "Based on actions taken by the President earlier this year, the United States has secured enough Pfizer and Moderna doses for 300 million Americans. Over the last few weeks, we have made available more than 25 million doses of Pfizer and Moderna each week, and in fact this week we will make available 28 million doses of these vaccines. This is more than enough supply to continue the current pace of vaccinations of 3 million shots."

At the White House press briefing on Tuesday, Zients called the FDA the "gold standard" for ensuring safety and efficacy of vaccines, and added that he believed that the pause would add to America's confidence in its vaccine regulatory system.

Supplies of the Johnson & Johnson vaccine were already limited after workers at a Maryland production plant mixed up ingredients for the Johnson & Johnson vaccine and the still-to-be-approved AstraZeneca vaccine. That mix-up led to the contamination of 15 million doses of Johnson & Johnson vaccine. According to CNBC, the government only allocated 700,000 doses of J&J vaccine this week, compared to nearly 5 million last week.

There is no indication that the mix-up at the Baltimore plant is responsible for the reports of blood clotting.

Officials also stressed Tuesday that there have not been any reports of clotting with either the Pfizer or Moderna vaccines, noting that 121 million people have taken those vaccines and that they are beginning to show real-world effectiveness.