The Centers for Disease Control and Prevention (CDC)’s Advisory Committee on Immunization Practices (ACIP) met on April 14, 2021 to discuss the recent cases of cerebral venous sinus thrombosis (CVST) with thrombocytopenia that occurred in 6 patients following receipt of the Janssen COVID-19 vaccine. Based on the available information, the panel was unable to decide on next steps for the Janssen COVID-19 vaccine, thereby extending their current recommendation for the pause.

What Is Known

There were 6 cases of CVST reported to the Vaccine Adverse Event Reporting System, all among women 18 to 48 years of age. Symptoms began 6 to 13 days after receiving the Janssen COVID-19 vaccine. Additionally, 1 report of CVST was observed in a 25-year-old male patient during the phase 3 clinical trial that supported authorization.

To date, 7,233,726 doses of the Janssen COVID-19 vaccine have been administered, of which 1,495,400 doses were administered to females 18 to 50 years of age. The Janssen COVID-19 vaccine comprises less than 5% of the COVID-19 vaccines administered. Approximately 13 million doses are currently available for use.

No cases of CVST with thrombocytopenia have been reported with the use of mRNA COVID-19 vaccines manufactured by Pfizer-BioNTech and Moderna. Thrombocytopenic thrombotic events have occurred following the administration of the AstraZeneca COVID-19 vaccine. Both the Janssen vaccine and the AstraZeneca vaccine contain replication-incompetent adenoviral vectors that encode the spike glycoprotein of SARS-CoV-2.


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What Is Not Known

Currently, it is unknown what the true incidence of CVST with thrombocytopenia is, or what the specific risk factors for this potentially life-threatening condition are, as it relates to the Janssen COVID-19 vaccine. Additionally, whether other thrombotic cases with thrombocytopenia may occur following receipt of the Janssen COVID-19 vaccine is unclear.

Recommendations for Healthcare Providers

Until a thorough assessment of the significance of these CVST cases can be made, the CDC continues to recommend a pause in the use of the Janssen COVID-19 vaccine. In patients who have recently received the Janssen COVID-19 vaccine, the following symptoms may warrant further investigation as they might represent serious thrombotic events or thrombocytopenia:

  • Severe headache
  • Backache
  • New neurologic symptoms
  • Severe abdominal pain
  • Shortness of breath
  • Leg swelling
  • Petechiae, or new or easy bruising

For patients with a thrombotic event and thrombocytopenia following vaccination, laboratory assessment for heparin-induced thrombocytopenia (HIT) using a PF4 enzyme-linked immunosorbent (ELISA) assay is recommended, as is consultation with a hematologist.

If HIT testing is positive or cannot be performed, treatment with heparin should be avoided. Rather, use of non-heparin anticoagulants and high-dose intravenous immune globulins should be considered.

For more information visit cdc.gov.

References

  1. U.S. Centers for Disease Control and Prevention. ACIP Presentation Slides: April 14, 2021 Meeting. https://www.cdc.gov/vaccines/acip/meetings/slides-2021-04.html. Accessed April 15, 2021.
  2. U.S. Centers for Disease Control and Prevention. Cases of cerebral venous sinus thrombosis with thrombocytopenia after receipt of the Johnson & Johnson COVID-19 vaccine. https://emergency.cdc.gov/han/2021/han00442.asp. Accessed April 15, 2021.