JAMA Network reported the findings of a case series, which aimed to describe the clinical and laboratory details of the first 12 US post-EUA cases of cerebral venous sinus thrombosis (CVST) with thrombocytopenia after Ad26.COV2.S (Janssen/Johnson & Johnson) COVID-19 vaccination reported to VAERS.
This case series may inform clinical guidance and investigations into the potential relationship between the Ad26.COV2.S vaccine and CVST with thrombocytopenia. In this case series of 12 patients, all were women, younger than 60 years, and had symptom onset ranging from six to 15 days after vaccination requiring hospitalization. Of 11 patients with heparin-platelet factor 4 enzyme-linked immunosorbent assay (ELISA) heparin-induced thrombocytopenia (HIT) antibody test results, all were positive. At last follow-up, outcomes were death, intensive care unit (ICU) care, non-ICU hospitalization and discharge to home.
CVST with thrombocytopenia, a rare and serious condition, has been described in Europe following receipt of the ChAdOx1 nCoV-19 vaccine (Oxford/AstraZeneca), which uses a chimpanzee adenoviral vector. A mechanism similar to autoimmune heparin-induced thrombocytopenia (HIT) has been proposed. In the US, the Ad26.COV2.S COVID-19 vaccine (Janssen/Johnson & Johnson), which uses a human adenoviral vector, received Emergency Use Authorization (EUA) on Feb. 27, 2021. By April 12, 2021, approximately seven million Ad26.COV2.S vaccine doses had been given in the US, and six cases of CVST with thrombocytopenia had been identified among the recipients, resulting in a temporary
Patients’ ages ranged from 18 to younger than 60 years; all were White women, reported from 11 states. Seven patients had at least 1 CVST risk factor, including obesity, hypothyroidism, and oral contraceptive use; none had documented prior heparin exposure. Time from Ad26.COV2.S vaccination to symptom onset ranged from 6 to 15 days. Eleven patients initially presented with headache; one patient initially presented with back pain and later developed headache. Of the 12 patients with CVST, seven also had intracerebral hemorrhage; eight had non-CVST thromboses. After diagnosis of CVST, six patients initially received heparin treatment.
The initial 12 US cases of CVST with thrombocytopenia after Ad26.COV2.S vaccination represent serious events. This case series may inform clinical guidance as Ad26.COV2.S vaccination resumes in the US as well as investigations into the potential relationship between Ad26.COV2.S vaccine and CVST with thrombocytopenia.
On March 18, 2021, the European Medicines Agency announced findings of a rare thrombosis with thrombocytopenia syndrome (TTS) after receipt of the ChAdOx1 nCoV-19 vaccine (Vaxzevria, Oxford/AstraZeneca), which uses a recombinant replication-deficient chimpanzee adenovirus vector. Cerebral venous sinus thrombosis (CVST), a rare and serious condition, was noted in 72% of these initial TTS reports. A mechanism similar to autoimmune heparin-induced thrombocytopenia (HIT), in which platelet-activating antibodies develop in the absence of heparin exposure, has been proposed to explain the occurrence of CVST with thrombocytopenia after ChAdOx1 nCoV-19 vaccination.
One case of CVST with thrombocytopenia in a male patient was reported during the phase 3 clinical trial of the Ad26.COV2.S vaccine. Six cases of CVST with thrombocytopenia after Ad26.COV2.S vaccination were reported through the Vaccine Adverse Event Reporting System (VAERS) to the Centers for Disease Control and Prevention (CDC) and FDA as of April 12, 2021; information about one case was published. On April 13, the CDC and FDA recommended a pause in the use of the Ad26.COV2.S vaccine. By April 21, six additional cases of CVST with thrombocytopenia and 3 cases of non-CVST TTS following administration of Ad26.COV2.S vaccine were reported to VAERS. On April 23, after reviewing data on TTS cases following post-authorization Ad26.COV2.S vaccination, CDC’s Advisory Committee on Immunization Practices (ACIP) reaffirmed its interim recommendation for use of the Ad26.COV2.S vaccine in all persons aged 18 years or older in the US.
