What to know about the distribution pause of Johnson & Johnson vaccine Staff report The CDC and FDA halted the distribution of the Johnson & Johnson COVID-19 vaccine on Tuesday, April 13, in order to review six reported cases of a rare and severe side effect that has resulted in at least one death. More than 6.8 million doses of the vaccine have been administered in the United States, according to the CDC. That makes the possibility of suffering from the rare side effect, a blood clot called cerebral venous sinus thrombosis, less than one in one million. Six women between the ages of 18 and 48 developed symptoms six to 13 days after receiving the Johnson & Johnson vaccine, according to the CDC.