By OLIVIA DAVIES, ABC News (NEW YORK) -- Federal health officials on Tuesday ordered a temporary stop on administering COVID-19 vaccine produced by Johnson & Johnson after reports of six people experiencing a blood clotting disorder. The Centers for Disease Control and Prevention and the Food and Drug Administration said in a joint statement the agencies were "recommending a pause" while more data pertaining to the single-shot vaccine is collected and reviewed. Nearly 7 million people in the U.S. have received J&J shots, and roughly 9 million more doses have been distributed for future use, according to CDC data. There have been no blood clotting cases reported so far tied to the Pfizer or Moderna vaccines, but if you've received the J&J single-dose vaccine -- and are concerned over potential side effects -- here's what you need to know.