F.After six cases of rare blood clots in women who received the COVID-19 vaccine from Johnson & Johnson in the US, the Food and Drug Administration and Centers for Disease Control and Prevention have recommended a temporary suspension of its introduction. In a statement released today (April 13), the agencies said they are investigating reports of cerebral venous sinus thrombosis (CVST), which is the same condition seen as an extremely rare side effect of AstraZeneca’s COVID-19 vaccine.
“Until this process is complete, we recommend taking a break from using this vaccine as a precaution,” the statement said. “This is important in part to ensure that the healthcare provider community is aware of the potential of these adverse events and can plan for their proper detection and treatment given the unique treatment that is required with this type of blood clot.” In particular, the authorities recommend that the anticoagulant heparin should not be used to treat patients in these situations. Geoffrey Barnes, an anticoagulation expert at the University of Michigan, told the Associated Press that other blood thinners and possibly an infusion of antibodies would be appropriate instead.
To date, nearly 7 million doses of Johnson & Johnson’s unique COVID-19 vaccine have been administered in the United States. The six reports of CVST included all women aged 18 to 48 who developed the clot between 6 and 13 days after vaccination. In addition to having clots, these individuals also had low platelet counts.
AstraZeneca and Johnson & Johnson both designed their vaccines to deliver some SARS-CoV-2 genetic material via an adenoviral vector, even though the virus ferries are different types of adenoviruses.
Of the 34 million people who received AstraZeneca’s COVID-19 vaccine, 169 developed CVST, according to Reuters, and the European Medicines Agency considers clotting to be a rare side effect of immunization. “The reported combination of blood clots and low platelets is very rare,” the EMA said in a statement last week, “and the vaccine’s general benefits in preventing COVID-19 outweigh the risk of side effects.”
It is not clear why these blood clots can appear after vaccination. “Of course there are hypotheses: maybe it’s something with the vector, maybe it’s an additive in the vaccine, maybe it’s something in the production process. . . . I don’t know, ”said Sabine Eichinger, hematologist at the Medical University of Vienna nature last week. “It could be one of those things.”
New York State, the City of Dallas, and federal government-coordinated mass vaccination events have suspended their Johnson & Johnson vaccination programs, according to the AP.