Atlanta, GA—Concerns about how cerebral venous sinus thrombosis (CVST) was being treated was one of the factors in the pause of Johnson & Johnson (J&J) COVID-19 vaccines, according to public health officials.

Six people who received the J&J vaccine developed the rare type of blood clot after receiving the vaccine, and their cases were reported to the Vaccine Adverse Event Reporting System (VAERS). About 6.85 million doses of the vaccine had been administered in the United States when the CDC and the FDA halted that program to review data involving cases of CVST, which was seen in combination with thrombocytopenia). The agencies subsequently issued an urgent health alert on the condition.

All six cases occurred among women aged 18 to 48 years over 6 to 13 days within receipt of the vaccine. Initial presenting symptoms included headache in five of six patients, and back pain in the sixth who subsequently developed a headache. While one patient also had abdominal pain, nausea, and vomiting, four developed focal neurological symptoms—focal weakness, aphasia, visual disturbance—leading to emergency care. All were eventually diagnosed with CVST by intracranial imaging; two patients were also diagnosed with splanchnic and portal vein thrombosis.

The alert notes that, in a situation not typical for patients presenting with thrombotic events, all six patients showed evidence of thrombocytopenia (<150,000 platelets per microliter of blood), consistent with a condition known as thrombotic thrombocytopenia, with platelet nadir counts ranging from 10,000 to 127,000 during their hospitalizations. Four patients developed intraparenchymal brain hemorrhage, and one subsequently died.

“Providers should maintain a high index of suspension for symptoms that might represent serious thrombotic events or thrombocytopenia in patients who have recently received the J&J COVID-19 vaccine,” the CDC stated in an official health alert. “When these specific types of blood clots are observed following J&J COVID-19 vaccination, treatment is different from the treatment that might typically be administered for blood clots.”

The alert goes on to say, “Based on studies conducted among the patients diagnosed with immune thrombotic thrombocytopenia after the AstraZeneca COVID-19 vaccine in Europe, the pathogenesis of these rare and unusual adverse events after vaccination may be associated with platelet-activating antibodies against platelet factor-4 (PF4), a type of protein. Usually, the anticoagulant drug called heparin is used to treat blood clots. In this setting, the use of heparin may be harmful, and alternative treatments need to be given.”

The health alert urges healthcare professionals to do the following:
• Maintain a high index of suspicion for symptoms that might represent serious thrombotic events or thrombocytopenia in patients who have recently received the J&J COVID-19 vaccine, including severe headache, backache, new neurologic symptoms, severe abdominal pain, shortness of breath, leg swelling, petechiae (tiny red spots on the skin), or new or easy bruising.
• Obtain platelet counts and screen for evidence of immune thrombotic thrombocytopenia.
• Evaluate patients with a thrombotic event and thrombocytopenia after the J&J COVID-19 vaccine initially with a screening PF4 enzyme-linked immunosorbent (ELISA) assay as would be performed for autoimmune heparin-induced thrombocytopenia (HIT). Consult with a hematologist if possible.
• Refrain from using heparin to treat patients with thrombotic events and thrombocytopenia following receipt of J&J COVID-19 vaccine, unless testing for the HIT antibody is negative.
• If HIT testing is positive or unable to be performed in patient with thrombotic events and thrombocytopenia following receipt of J&J COVID-19 vaccine, strongly consider using nonheparin anticoagulants and high-dose IV immune globulin for treatment.
• Report adverse events to the FDA’s Vaccine Adverse Event Reporting Center, including serious and life-threatening adverse events and deaths in patients following receipt of COVID-19 vaccines as required under the emergency-use authorizations for COVID-19 vaccines.

Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, predicted that the J&J coronavirus vaccine will continue to be used “in some form.” He suggested that some types of warning or restrictions are likely, however.

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