So far, patients with a rare and dangerous blood clotting syndrome linked with Johnson & Johnson’s coronavirus vaccine have started showing symptoms one to two weeks after getting the vaccine, a US Centers for Disease Control and Prevention expert said Friday.
And symptoms are similar to those seen among people who experienced blood clots after getting AstraZeneca’s vaccine in Europe and the UK, the CDC’s Dr. Tom Shimabukuro told a meeting of the CDC’s Advisory Committee on Immunization Practices.
The CDC and the US Food and Drug Administration recommended pausing the use of the Johnson & Johnson vaccine after six reported cases of women who developed a rare blood clotting syndrome called thrombosis with thrombocytopenia syndrome, or TTS, after receiving the Johnson & Johnson vaccine in the United States. Now 15 cases have been reported, Shimabukuro said – all of them among women.
During the clinical trial of the vaccine last fall, one man experienced clots 21 days after taking the vaccine, according to J&J. That was case was previously presented to CDC, but was not included in the agency’s analysis of cases seen after the vaccine was authorized and distributed to the public.
“So to sum up, TTS is rare but clinically serious and potentially life threatening adverse event that has been observed in association with the Janssen Covid-19 vaccine,” Shimabukuro said.
“Symptom onset appears to occur at least several days after vaccination, typically around one to two weeks after vaccination,” he added.
“The clinical features of TTS following the Janssen Covid-19 vaccine appear similar to what is being observed following the AstraZeneca Covid-19 vaccine in Europe. It is important to recognize TTS early and initiate appropriate treatment.”
The main danger is using a common blood thinner called heparin. Other blood thinners are safe to use, and experts are also recommending use of an immune product called IVIG to restore the balance of blood-clotting cells.
“We will certainly continue our enhanced surveillance for this,” Shimabukuro said.
ACIP is expected to vote on any changes to its guidance for J&J’s vaccine later Friday. If ACIP recommends changes to the vaccine label – such as a warning, or changes to who it recommends should get the vaccine – CDC Director Dr. Rochelle Walensky will sign off and then the FDA will have to make any label changes.