https://www.siliconvalley.com/2021/04/27/covid-what-women-should-know-about-the-johnson-johnson-vaccine/

(CNN) — The US Centers for Disease Control and Prevention and the US Food and Drug Administration lifted the pause on the Johnson & Johnson Covid-19 vaccine on Friday. The agencies previously had decided to pause administration of the vaccine due to cases of an extremely rare blood clotting disorder found in six women between the ages of 18 and 49 who had gotten the shot.

The initial pause was intended to inform health care providers about this rare disorder and its treatment, and to see if other cases would emerge.