The Food and Drug Administration and the Centers for Disease Prevention and Control said Tuesday morning that they’re recommending that states pause the rollout of the single-shot Johnson & Johnson vaccine over concerns about blood clots.
The pause in the rollout came after six recipients in the United States developed “a rare and severe type of blood clot” within about two weeks of vaccination.
All six recipients were women between the age of 18 and 48. One woman has died and a second woman in Nebraska has been hospitalized in critical condition, the New York Times reported.
To date, over 6.8 million people have been given the Johnson & Johnson vaccine, with 9 million more doses already shipped to states.
In a statement, the FDA said: “We are recommending a pause in the use of this vaccine out of an abundance of caution. Right now, these adverse events appear to be extremely rare.”
The CDC and the FDA will now begin investigating the link between the vaccine and the blood clots. The CDC has scheduled a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday “to further review these cases and assess their potential significance.”
The type of blood clot that cropped up in these six cases, cerebral venous sinus thrombosis in combination with low levels of blood platelets, can’t be treated with the usual anticoagulant, a medication called heparin, Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said during a press briefing Tuesday. But pausing the use of the Johnson & Johnson vaccine will give health care providers time to recognize and learn how to properly treat the clots, in the rare event that they occur.
People who received the Johnson & Johnson vaccine within the past couple of weeks, should be aware of symptoms including severe headache, abdominal pain, leg pain, or shortness of breath—which differ from the regular, flu-like symptoms some people have reported getting the jab.
The pause is expected to last “a matter of days,” Acting FDA Commissioner Janet Woodcock said. Jeffrey Zients, the White House Covid-19 response coordinator, said in a statement Tuesday that it shouldn’t have a significant impact on the country’s vaccination program, noting that the Johnson and Johnson shot has made up less than 5% of the recorded shots to date.
“We are committed to safety and transparency, and to expeditiously learning as much as we can so that further steps can be taken,” Anne Schuchat, Principal Deputy Director of the CDC, said in the media briefing Tuesday.
“When we saw this pattern and were aware that treatment needed to be individualized for this condition, it was of the utmost importance for us to get the word out.”
“That said,” she continued, “the pandemic is quite severe, and cases are increasing in a lot of places. And vaccination is critical. So we want to make sure that we make some recommendations quickly.”
Johnson & Johnson in a statement said it was aware of the decision to pause the rollout of the vaccine and the reasons behind it.
“We are aware that thromboembolic events including those with thrombocytopenia have been reported with Covid-19 vaccines. At present, no clear causal relationship has been established between these rare events and the Janssen Covid-19 vaccine,” the company said on Tuesday morning.
This is not the first time concerns have been raised about blood clots linked to the Johnson & Johnson vaccine.
Last week the European Medical Agency announced it was investigating four cases of blood clots in people who had been given the Johnson & Johnson vaccine in the U.S., one of whom had died as a result of the clot. The announcement on April 9 came just a month after the EMA had initially approved the single-shot vaccine for use in the European Union. For now, however, the rollout in the EU is still going ahead. The first deliveries of the vaccine began shipping to member states on Monday.
Luckily, the clots in combination with low platelet counts aren’t being seen with the Pfizer-BioNTech and Moderna vaccines, U.S. health officials said Tuesday.
This article has been updated throughout to reflect recent developments.