The CDC and FDA announced Friday evening that Johnson & Johnsonâs Jassen COVID-19 (J&J) vaccine could be administered again, following a thorough safety review. The departments recommended a pause on the vaccineâs use on April 13 after six cases of ârare and severeâ blood clots were reported in individuals after receiving the J&J vaccine. According to the CDC, teams at the FDA and CDC examined data to assess the risk of âthrombosis involving the cerebral venous sinuses,â which are large blood vessels in the brain, as well as other sites in the body such as the abdomen and legs. They also looked at thrombocytopenia, or low blood platelet counts.Â