Federal health agencies on Tuesday recommended stopping the use of the Johnson & Johnson vaccine after a small number of people experienced a “rare and severe type of blood clot” after receiving the shot.
The Food and Drug Administration and the Centers for Disease Control & Prevention have issued a statement saying they “out of caution recommend a break in the use of this vaccine.”
About 6.8 million people have received the single-vaccine vaccine in the United States. Six of them experienced the blood clot, the agencies said, adding: “At the moment, these adverse events appear to be extremely rare.”
The news was first reported by The New York Times.
In a statement, Johnson and Johnson said they were aware that blood clots had been reported with some Covid-19 vaccines, but that no clear causal link had been established between these rare events and their shots.
“We continue to work closely with experts and regulators to assess the data and support the public communication of this information to health professionals and the public,” he said.
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The six people who had blood clots were all women between the ages of 18 and 48, who started getting symptoms between six and 13 days after vaccination, the FDA and CDC said. They had a cerebral venous sinus thrombosis, or CVST, as well as low levels of platelets.
“The treatment of this specific type of blood clot differs from the treatment that can usually be given,” the statement read. Clots are usually treated with an anticoagulant called heparin, but it can be dangerous to use on CVST.
The CDC will convene a meeting of its Advisory Committee on Immunization Practices on Wednesday, which will provide guidance on vaccines.
The committee is said to be “further investigating these matters and assessing their potential significance”, while the FDA will also investigate. “Until the process is completed, we recommend this pause,” the joint statement said. The FDA is holding a news conference on Tuesday at 10:00 a.m.
The call for a halt reflects the situation in Europe last month.
Some European governments have stopped vaccinating the Oxford University AstraZeneca vaccine after a similarly small number of people contracted CVST blood clots. The AstraZeneca vaccine uses the same type of technology as the Johnson & Johnson shot.
Most European countries have since resumed application, but with a messy patchwork of different age restrictions and other guidelines. There is evidence that public confidence in this vaccine is lower than others available due to this fear that is widely known.
The situation in Europe divided experts, with some saying governments could not ignore the possible link, and others saying the disruption could potentially cause infections and hesitation, weighing as much as the dangers of these extremely rare side effects.
