Doctors across the country are on their guard for rare blood clots associated with the Johnson & Johnson Covid-19 vaccine since the shot went silent Tuesday.
“We can not afford to miss it,” said Dr. Mary Cushman, a hematologist and medical director of the thrombosis and hemostasis program at the University of Vermont Medical Center.
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The administration of the Johnson & Johnson vaccine was suspended on Tuesday after six recipients developed cerebral venous sinus thrombosis, or CVST, which could lead to blood clots in the blood vessels, in combination with low platelet levels.
Overall, 7.6 million people in the United States have received the shots, which means that the six cases so far are extremely rare – although serious.
“You will not find a doctor in the country” who does not have to reconsider how to recognize and treat such blood clots in patients, said dr. Anand Padmanabhan, a senior associate consultant in the Department of Laboratory Medicine and Pathology at the Mayo Clinic in Rochester, Minnesota. “Things are changing fast.”
“We have reached more than 10,000 suppliers to ensure they know what cases to look for,” said Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, told a news conference Friday.
One patient, a woman in Virginia, died and four others have not yet recovered. Only one was discharged from the hospital. All cases were in white women between 18-48 years. Three of the women also developed blood clots in other parts of the body.
Cushman said every provider in her health network has received guidance on the issue. For each patient with a blood clot, doctors are instructed to ask if they have received a Covid-19 vaccine, and if so, which one.
In addition to Johnson & Johnson, similar blood clots have also been linked to the AstraZeneca vaccine. That vaccine is not authorized in the US, but is used in other countries.
“You can have a visitor fly to the US who got a vaccine a few days earlier in Europe or elsewhere,” Padmanabhan said.
Doctors are also instructed to ask when the individual received the vaccine. The timing of the vaccination appears to be important; the six patients who received blood clots became ill six to 13 days after receiving the Johnson & Johnson shot.
Blood tests are also critical, doctors said. The blood clots specific for the six patients linked to the Johnson & Johnson vaccine were found in combination with a low level of platelets – an important clue that can be measured with a blood test.
Despite the heightened warning, it is unlikely that most doctors will encounter such a situation, as the occurrence of blood clots apparently related to the Johnson & Johnson vaccine is extremely rare at this stage.
Blood clots in general are not uncommon. One type, called a deep vein thrombosis, affects up to 900,000 people annually. Experts say the two are not related because a person received the Johnson & Johnson vaccine and subsequently developed a blood clot.
After all, it is essential to have the skills to recognize the condition, especially for appropriate treatment.
In an information session earlier this week, dr. Peter Marks, director of the Center for Biological Evaluation and Research at the Food and Drug Administration, said that these rare cases should be treated differently from typical blood clots.
Usually, the standard of care for clotting problems is a blood thinner called heparin, which is administered intravenously. But in rare cases, the medication does the opposite, causing platelets to clot. This is similar to what was observed in the Johnson & Johnson cases. The concern is that the administration of heparin to such patients will aggravate their condition.
Other intravenous blood thinners are available, such as argatroban. Padmanabhan, who is part of a group tasked with developing leaders for doctors in the Mayo Clinic Health System, said intravenous immunoglobulin, a plasma-rich antibody infusion, should also be considered in combination with blood thinners.
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Dr. Katie Passaretti, medical director for infection prevention at Atrium Health in Charlotte, North Carolina, said the symptoms are severe and noticeable to people who have received the Johnson & Johnson vaccine.
“The things that cause the most concern are severe headaches – like the worst headaches in your life that last for several days,” Passaretti said.
Other possible symptoms may include neurological problems, such as difficulty speaking, as well as shortness of breath or significant swelling in the body.
Further clarity from federal officials is only expected after April 23, when the CDC’s Advisory Committee on Immunization Practices will meet again.
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