Federal officials are concerned that doctors may not be trained to look for the rare disorder if recipients of the vaccine develop symptoms of it. The federal health agencies said Tuesday morning that “treatment of this specific type of blood clot is different from the treatment that might typically be administered” for blood clots.
“Usually, an anticoagulant drug called heparin is used to treat blood clots. In this setting, administration of heparin may be dangerous, and alternative treatments need to be given,” the statement said.
Dr. Schuchat, the C.D.C. official, said that the risk of dangerous blood clots was “very low” for people who received Johnson & Johnson’s vaccine more than a month ago.
“For people who recently got the vaccine within the last couple of weeks, they should be aware to look for any symptoms. If you receive the vaccine and develop severe headaches, abdominal pain, leg pain or shortness of breath, you should contact your health care provider and seek medical treatment,” she said.
Johnson & Johnson said in a statement that “at present, no clear causal relationship has been established between these rare events and the Janssen Covid-19 vaccine.” Nonetheless, the firm said, it was delaying the rollout of its vaccine in Europe. Janssen is the name of Johnson & Johnson’s division that developed the vaccine.
In the United States alone, 300,000 to 600,000 people a year develop blood clots, according to C.D.C. data. But the particular blood clotting disorder that the vaccine recipients developed, known as cerebral venous sinus thrombosis, is extremely rare. Dr. Schuchat described the condition as “a severe strokelike illness linked to low platelet counts.”
All of the women developed the illness within about one to three weeks of vaccination, with a median time of nine days. The Nebraska woman who is now hospitalized is in her late 40s and developed blood clots two weeks after her shot, state health officials said.