Thrombosis with Thrombocytopenia Syndrome

Based on an updated risk-benefit analysis,  mRNA COVID-19 vaccines are preferred over the Janssen COVID-19 Vaccine for all vaccine-eligible people. However, the Janssen COVID-19 Vaccine may be offered in some situations as described below:

  • When there is a contraindication to mRNA COVID-19 vaccines (e.g., severe allergic reaction after a previous dose or to a component of an mRNA COVID-19 vaccine)
  • When a person would otherwise remain unvaccinated for COVID-19 due to limited access to mRNA COVID-19 vaccines.
  • When a person wants to receive the Janssen COVID-19 Vaccine despite the safety concerns identified

All people who elect to receive a Janssen COVID-19 Vaccine should be informed about the risk and symptoms of TTS that could occur after vaccination (typically within 2 weeks after receipt), the need to seek immediate medical care should such symptoms develop at any time, and the availability of mRNA COVID-19 vaccines instead of the Janssen COVID-19 Vaccine.

This guidance applies to the both primary and booster doses of Janssen COVID-19 Vaccine.



Page last reviewed: March 8, 2022