Michigan Medicine blood clotting expert explains J&J vaccine pause

‘We do not yet know if there is a real risk of clotting associated with the J&J vaccine’

FILE  In this March 31, 2021 file photo, a nurse fills a syringe with a dose of the Johnson & Johnson's one-dose COVID-19 vaccine at the Vaxmobile, at the Uniondale Hempstead Senior Center, in Uniondale, N.Y. The U.S. is recommending a pause in administration of the single-dose Johnson & Johnson COVID-19 vaccine to investigate reports of potentially dangerous blood clots. In a joint statement Tuesday, the Centers for Disease Control and Prevention and the Food and Drug Administration said it was investigating clots in six women in the days after vaccination, in combination with reduced platelet counts. (AP Photo/Mary Altaffer, File)
FILE In this March 31, 2021 file photo, a nurse fills a syringe with a dose of the Johnson & Johnson's one-dose COVID-19 vaccine at the Vaxmobile, at the Uniondale Hempstead Senior Center, in Uniondale, N.Y. The U.S. is recommending a pause in administration of the single-dose Johnson & Johnson COVID-19 vaccine to investigate reports of potentially dangerous blood clots. In a joint statement Tuesday, the Centers for Disease Control and Prevention and the Food and Drug Administration said it was investigating clots in six women in the days after vaccination, in combination with reduced platelet counts. (AP Photo/Mary Altaffer, File) (Copyright 2021 The Associated Press. All rights reserved.)

A Michigan Medicine blood clotting expert is weighing in on the FDA and CDC’s decision to pause the Johnson & Johnson (J&J) COVID-19 vaccine due to a rare blood clotting condition.

The United States health officials said six women who received the vaccine experienced blood clots in the brain within two weeks after vaccination. There have been only six such cases reported after more than 6.8 million people in the United States received the one-dose COVID-19 vaccine.

“Right now, these adverse events appear to be extremely rare,” reads the statement from the FDA on Tuesday morning. “Treatment of this specific type of blood clot is different from the treatment that might typically be administered. CDC will convene a meeting of the Advisory Committee on Immunization Practices (ACIP) on Wednesday to further review these cases and assess their potential significance. FDA will review that analysis as it also investigates these cases. Until that process is complete, we are recommending this pause. This is important to ensure that the health care provider community is aware of the potential for these adverse events and can plan due to the unique treatment required with this type of blood clot.”

The FDA later said Tuesday morning that the pause to the Johnson & Johnson COVID-19 vaccine to investigate rare blood clots is expected to last a “matter of days.”

Cardiologist and vascular medicine specialist Dr. Geoffrey Barnes, who works at the Michigan Medicine Frankel Cardiovascular Center, is offering some explanation about the pause and rare cases of blood clotting.

Here’s what University of Michigan Health reported Tuesday from Barnes:

What is your take on the concerns about blood clotting after the Johnson & Johnson/Janssen vaccine?

Barnes: It’s important to note that we do not yet know if there is a real risk of clotting associated with the J&J/Janssen vaccine. So far, there are very few reported cases (six) despite millions of doses administered. However, given the events in Europe and Canada that appear to be associated with the AstraZeneca vaccine (which is not currently available in the U.S.), I think it’s wise to pause to investigate these cases.

There has been a specific mechanism proposed for the rare clotting events after the AstraZeneca vaccine, and we don’t yet know if the same mechanism might be involved with these clotting events found after the Janssen vaccine.

What should people who have already gotten the Johnson & Johnson/Janssen vaccine know?

Barnes: Keep an eye on how you’re feeling. Clinicians and patients should watch for any signs or symptoms that can signify a clot within 1-3 weeks after the AstraZeneca or J&J/Janssen vaccine. Those may include severe headache, vision changes, severe abdominal pain, or nausea and vomiting.

Notably, if patients develop muscle aches, chills, or nausea and vomiting within 1-2 days after the vaccine, that is likely a known side effect of the vaccine and not related to a clot. But if these develop 4-5 days after the vaccine, patients should be evaluated for a possible rare blood clot.

If a patient does develop signs or symptoms of a clot within three weeks after an AstraZeneca or J&J/Janssen vaccine, evaluation with routine coagulation tests and imaging is recommended. If thrombocytopenia (low platelets) are found, work up for vaccine-induced thrombotic thrombocytopenia (VITT; similar to heparin-induced thrombocytopenia) and avoiding heparin anticoagulation is recommended until further testing can be completed.

What should you do if you already have an appointment for this vaccine?

Barnes: Check with the place you’re registered with to see if they’re pivoting to other vaccine manufacturers or if you’ll have to make a later appointment.

What other common medications do we take that give us a risk of blood clots?

Barnes: Many women use estrogen-containing oral contraceptive pills. These pills are associated with a risk of blood clots, including the rare clots that have been seen with the AstraZeneca vaccine.

What is the final message you’d like readers to know?

Barnes: COVID-19 is a serious public health crisis. Vaccines are a critical element to getting the pandemic under control.

The blood clots identified after the AstraZeneca and Janssen/Johnson & Johnson vaccine are concerning, but seem to be quite rare. Physicians are aware of this condition and have the necessary tools to diagnose and treat patients if this very rare condition occurs.

Furthermore, there has not been a sign of blood clot risk following the Pfizer or Moderna COVID-19 vaccines. Therefore, I strongly urge everyone to get vaccinated as soon as possible.



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