Johnson & Johnson’s Janssen COVID-19 Vaccine: The CDC and FDA have recommended that Johnson & Johnson’s Janssen (J&J / Janssen) COVID-19 vaccine be relaunched in the United States, effective April 22, 2021. However, women under the age of 500 should be aware of the rare risks. Blood clots with low platelets after vaccination, and other COVID-19 vaccines are available where this risk is not seen. If you received the J&J / Janssen vaccine, Here’s what you need to know. Read on CDC / FDA statement.