According to health officials, one woman has died and another is in critical condition.
However, the chance of getting blood clots from the vaccine is being called a rare event, and the pause will be used to investigate the clots.
"I'd like to stress these events appear to be extremely rare. However, COVID-19 vaccine safety is a top priority," FDA Acting Commissioner Janet Woodcock said during a news conference. "We expect it to be a matter of days for this pause."
The U.S. has administered more than 6.8 million doses of the single-shot vaccine, with most people having mild or no side effects.
If you have gotten the vaccine, you should not be worried about severe side effects, according to Dr. Matthew Sims, the director of infectious disease research at Beaumont.
"It is scary and I can understand why anyone who has gotten the J&J vaccine up to this point might be worried," Sims said. "I would be cautious on jumping the gun and worrying that I’m definitely going to get it because I got the shot."
Sims said he does not recommend taking aspirin or other measures in an attempt to prevent side effects from the Johnson & Johnson vaccine until health officials know more about it.
"We don’t know what risk factors they had going into it. There’s a lot more we don’t know than we do know, and so rightfully the FDA and the CDC have called a pause to investigate, to figure out is this a problem? If it is a problem, is it so big a problem they need to stop using it, or is it something that can be used safely in the right people? That’s what we don’t know yet," he said.
Sims added that the vaccine's pause does not mean it is being taken off the market, and this time is being used to understand more about the blood clots that six people developed. He said the benefits of the vaccine are greater than the chances of a severe reaction.
"The benefits of the vaccine are very clear. This risk is not as clear, and it is very, very, very rare," he said. "Less than one in a million people have gotten this side effect."
Both the FDA and CDC are recommending that people who received the vaccine who experience severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after receiving the shot should contact their doctor.