Federal health officials on Tuesday recommended discontinuing use of the Johnson & Johnson vaccine after a small number of people had “a rare and severe type of blood clot” after receiving the shot.
The Food and Drug Administration and Centers for Disease Control and Prevention issued a statement saying they would “out of caution, recommend a break in the use of this vaccine”.
In the United States, around 6.8 million people have received the single vaccine. Of those, six experienced the clot, the agencies said, adding, “Right now, these adverse events seem extremely rare.”
The message was first reported by The New York Times.
In a statement, Johnson & Johnson said it was known that some Covid-19 vaccines had reported blood clots but that “no clear causal link has been established between these rare events” and their shot.
“We continue to work closely with experts and regulators to evaluate the data and support open communication of this information with health professionals and the public,” it said.
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The six people who developed blood clots were all women between the ages of 18 and 48 who developed symptoms between six and 13 days after vaccination, the FDA and CDC said. You have had a condition called cerebral venous sinus thrombosis (CVST) and low blood platelet levels.
“Treatment for this specific type of blood clot is different from treatment that is normally given,” the statement said. Clots are usually treated with an anticoagulant called heparin – but that drug could be dangerous in CVST, it said.
The CDC will hold a meeting of its Advisory Committee on Immunization Practices on Wednesday to provide guidance on vaccines.
The committee will “continue to review these cases and assess their potential significance” while the FDA will investigate these as well. “Until this process is completed, we recommend this break,” said the joint statement. The FDA will hold a press conference on Tuesday at 10 a.m.
The call for a break reflects a situation that played out in Europe over the past month.
Some European governments suspended the launch of the Oxford-AstraZeneca University vaccine after a similarly small number of people suffered from CVST blood clots. The AstraZeneca vaccine uses the same technology as the Johnson & Johnson shot.
Most European countries have since resumed administration of the shot, but with a chaotic patchwork of various age restrictions and other guidelines. There is evidence that, due to this widespread fear, public confidence in this vaccine is lower than in others that are available.
The situation in Europe has divided experts, with some saying governments could not ignore the possible link and others saying the hiatus could lead to increased infections and hesitation, harms that far outweigh the dangers of these extremely rare side effects.