Nearly seven million people in the United States have received Johnson & Johnson shots so far, and roughly nine million more doses have been shipped out to the states, according to data from the C.D.C. The six women who developed blood clots were between the ages of 18 and 48. One woman died and a second woman in Nebraska has been hospitalized in critical condition.
“We are recommending a pause in the use of this vaccine out of an abundance of caution,” Dr. Peter Marks, director of the Food and Drug Administration’s Center for Biologics Evaluation and Research, and Dr. Anne Schuchat, principal deputy director of the C.D.C., said in a joint statement. “Right now, these adverse events appear to be extremely rare.”
“I know there are people who have gotten the vaccine, who are probably very concerned. For people who got the vaccine more than a month ago, the risk to them is very low at this time,” Dr. Schuchat said. “For people who recently got the vaccine within the last couple of weeks, they should be aware to look for any symptoms.”
Like many states, New York had already prepared for a significant drop in its supply of the Johnson & Johnson vaccine after federal officials said that supplies would be limited because of a production issue at a Baltimore manufacturing plant. On Friday, Gov. Andrew M. Cuomo said that New York expected to receive 34,900 Johnson & Johnson shots, a decrease of 88 percent from the previous week.
Dr. Zucker, New York’s health commissioner, said that the state would honor appointments made at state-run mass vaccination sites for the Johnson & Johnson vaccine by giving people the Pfizer-BioNTech vaccine instead. That vaccine requires two doses, and it was not immediately clear how the state would handle the additional strain on its supply.
New Jersey health officials said the state would work with its vaccination sites to help people get appointments for the Pfizer or Moderna vaccine instead. Mayor Bill de Blasio of New York City said that the city would do the same, rescheduling appointments at city-run vaccine sites.
“Every site has been told this morning to stop giving the J&J shots,” he said at a news conference.
The city’s health commissioner, Dr. Dave Chokshi, said that around 234,000 residents have received the Johnson & Johnson vaccine and none had reported any blood clots so far. The city had been relying on the vaccine to inoculate hard-to-reach New Yorkers, including people who are homebound.