Local leaders are pausing use of the Johnson & Johnson COVID-19 vaccine this week at the recommendation of federal health officials, who say they are reviewing extremely rare but severe blood clots identified in six women who had received the vaccine.

The Centers for Disease Control and Prevention and the Food and Drug Administration issued a joint statement Tuesday morning recommending vaccine distributors delay use of Johnson & Johnson’s doses out of an “abundance of caution,” while they investigate the cause of the blood clots. More than 6.8 million doses of the vaccine have been distributed in the U.S. The CDC is investigating the death of a Richmond woman as one of the six recipients who developed the rare blood disorder within about two weeks of receiving the Johnson & Johnson vaccine, according to a Virginia Health Department statement on Tuesday. 

DC Health officials say 16,000 Johnson & Johnson doses have been distributed in the District, with no reports of the rare blood clots.

The District cancelled all appointments for the Johnson & Johnson vaccine from Tuesday through April 17. The roughly 1,200 individuals who had an appointment scheduled through the DC Health portal to receive the Johnson & Johnson vaccine during those dates will receive an email at some point on Tuesday to book an appointment this week or next week for another vaccine, DC Health official said. (Individuals should remember to check their spam folders for these emails.) An additional 8,000 doses of the Johnson & Johnson vaccine went to federal partnerships within the city this week, like independent pharmacies and federal government agencies, according to DC Health director LaQuandra Nesbitt. During a press call on Tuesday, Nesbitt said these agencies and retailers are communicating with individuals to reschedule their appointments, and added that the city is not aware of any providers that are not following the federal guidance for a temporary pause.

For the roughly 1,200 Johnson & Johnson appointments booked through DC Health, Nesbitt said the department will reschedule individuals to receive doses that were set aside for appointments this week that were not booked, or it will prioritize those individuals for next week. (As has been in the case in weeks past, not everyone who is notified of appointment availability claims an appointment within the given 48 hour window.)

Nesbitt noted that the pause will, however, impact the city’s plans to launch a program for homebound seniors, who likely would have relied on the Johnson & Johnson vaccine. It may also impact the city’s vaccination efforts for residents experiencing homelessness. Residents experiencing homelessness or those within the Department of Human Services’ shelter programs have received the Johnson & Johnson vaccine as part of a partnership with Unity Health; the city also recently stood up walk-up clinics for unhoused residents. (Johnson & Johnson’s has been the primary vaccine used at distribution sites like these walk-ups due to its one-shot efficacy that doesn’t require individuals to travel to two appointments weeks apart, unlike the Pfizer and Moderna vaccines.)

During the press call, Nesbitt said the agency is “optimistic” that Unity Health, which originally began vaccinating residents with Moderna, can transition back to using doses of the Moderna vaccines to keep the sites functioning. For the high-capacity sites that have also been using Johnson & Johnson, Nesbitt said there is availability to use Moderna and Pfizer vaccines at these locations this week.

Virginia’s Health Department issued a statement temporarily halting the administration of the Johnson & Johnson vaccine on Wednesday morning. According to VDH’s statement, those with appointments for the Johnson & Johnson vaccine will be contacted to reschedule.

Arlington County, which had been using the Johnson & Johnson shot at its public health clinics, will also pause distribution. People who have appointments Tuesday at the Lubber Run Community Center, which was using the Johnson & Johnson vaccine, will be given the Moderna vaccine, according to a statement from the county. The clinics will continue “to the extent [the county] receives doses of Pfizer or Moderna” over the coming days, a statement said. Appointments may be rescheduled depending on dose availability. The city of Alexandria similarly announced that anyone scheduled to receive the Johnson & Johnson vaccine will be contacted to reschedule their appointment, or receive either the Pfizer or Moderna vaccine. Fairfax County did not receive any Johnson & Johnson vaccines for this week or the following, according to a statement from the county. A small number of doses left over from last week’s Johnson & Johnson allotment will be substituted with Moderna or Pfizer doses, to avoid any cancellation of appointments this week.

Maryland has directed all providers to pause all administration of the Johnson & Johnson vaccine until more federal guidance is available. Montgomery County, which set to use 960 doses of the Johnson & Johnson vaccine at the mass vaccination site in Germantown on Tuesday, will pause administration and offer the Pfizer vaccine instead, according to a county spokesperson. The Deputy Chief Administrative Officer for Health, Human Services and Education in Prince George’s County said that the county has 738 doses of the Johnson & Johnson vaccine on hand, but will not need to reschedule any appointments as a result of the pause.

“While we are presently looking at the impact of this recent announcement, it appears the greatest impact will be the Health Department’s ability to schedule clinics to full capacity due to the combined recent decrease in availability of other vaccine options,” Dr. George Askew said in an emailed statement.

The pause comes amidst an already-lowered supply of the Johnson & Johnson vaccine in the region this week, and as parts of the D.C. region expand eligibility to all residents over age 16.

Across D.C., Maryland, and Virginia, the allotment of the Johnson & Johnson vaccine decreased by 85% this week, compared to the week prior due to production issues at a Baltimore plant manufacturing the vaccine. According to CDC data, D.C., Maryland, and Virginia combined received 16,100 doses of the Johnson & Johnson vaccine this week. D.C. received 1,300 – accounting for around 6.8% of its total allotment for first-doses this week. Maryland received 10,500 doses of the one-shot, while Virginia received 14,800 — both around 6.8% of the states’ total federal allotments for first doses this week.

On Tuesday, White House COVID-19 Response Coordinator Jeff Zients said the pause will not have a “significant impact” on the country’s vaccination plan, and that the White House will make an additional 28 million doses of Moderna and Pfizer vaccines available this week. According to Zients, the U.S. has secured enough doses of the Moderna and Pfizer vaccines to continue vaccinating Americans at the rate of 3 million people per day.

During the press call on Tuesday, Nesbitt said the temporary pause means that “the system is working” to flag any potential safety issues with vaccines. It’s not yet clear whether the blood clots reported in the women who received the Johnson & Johnson vaccine were a side effect of their doses, and health officials, including White House Chief Medical Advisor Dr. Anthony Fauci, have sought to allay concerns about the vaccine among those who have received it Nesbitt issued a reminder that the Moderna and Pfizer vaccines have not been linked to the rare blood clot, cerebral venous sinus thrombosis (CVST), with low blood platelets . She said anyone who has appointments booked for either the Moderna and Pfizer shots should keep them, adding that the pause will not impact the city’s recent expansion of eligibility to all residents 16 and older.

“Vaccine safety has remained a priority throughout the implementation of the COVID-19 vaccine program in the district and the U.S. as a whole. The identification of this rare syndrome allows for us to be able to think collaboratively as a public health community about any additional directions that should be taken around the J&J vaccines,” Nesbitt said. “Individuals who have concerns about vaccine confidence are reminded to weigh the benefits of vaccination and any potential risk of vaccinations against the risk of acquiring COVID-19 infection.”

Still, she reminded the 16,000 people who have received a Johnson & Johnson vaccine to continue to monitor their symptoms, although the blood clot disorder is extremely rare. Fauci, the nation’s leading infectious disease expert,  issued a similar sentiment during a White House briefing on the pause Tuesday, reminding people that the odds of the blood clot disorder are less than one in a million.