Retail pharmacies that have been administering the COVID vaccine have already reacted to the announcement from the Food and Drug Administration to pause the use of the Johnson & Johnson COVID shot.

Large drugstore chains such as CVS, Walgreens, and Kroger have announced that they are canceling all vaccination appointments that were slated for the Johnson & Johnson shot and are looking to fill those slots with Pfizer and Moderna doses.

The FDA announced on Tuesday that it was recommending the use of the Johnson & Johnson vaccine be paused after six reports of women with blood clots.

The women aged 18 to 48 had cerebral venous sinus thrombosis – a brain blood clot – which is considered a very rare disorder- occurring in five people in 1 million every year, according to Cedars Sinai.

The blood clots all occurred six to 13 days after patients received the Johnson & Johnson vaccine, according to the FDA. One vaccine recipient died while another is currently in critical condition, an agency official said during a media briefing.

Retailers are now tasked with rolling out the vaccine to eligible recipients while managing the new information from the FDA as they administer COVID shots under the Federal Retail Pharmacy Program.

CVS announced on its website that it had paused all Johnson & Johnson vaccines until further notice.

Mike DeAngelis, a CVS spokesman, told CNBC that all impacted customers would receive an email to notify them their shot appointment had been canceled, with a follow-up notice to customers to reschedule as CVS continues to offer shots by other vaccine manufacturers.

Walgreens said in a statement that it was suspending the Johnson & Johnson vaccine at its stores and off-site clinics as it awaits further guidance. The company is currently reaching out to vaccine recipients that had appointments to reschedule them for a vaccine from another maker as supply allows.

Also pausing the Johnson & Johnson vaccine is grocery giant Kroger, which said on its website that “In accordance with CDC and FDA guidance issued out of an abundance of caution, we have paused administering the Johnson & Johnson COVID-19 vaccine. Pfizer and Moderna 2-dose vaccines remain available.”

It was unclear if Kroger was rescheduling or canceling appointments made for the Johnson & Johnson COVID vaccine.

Rite Aid also said it was temporarily pausing all Johnson & Johnson vaccinations while the CDC and FDA investigate the rare blood clot condition. The drugstore and pharmacy retailer said that it has made the decision “out of an abundance of caution” until it learns more.

All vaccination appointments for the Johnson & Johnson shot at Rite Aid scheduled for Tuesday and Wednesday have been canceled. Customers will be notified with a link to review appointment availability for a Pfizer or Moderna vaccine in their area, the company said.

About 6.8 million of Johnson & Johnson’s one-dose COVID vaccines have been administered to date.

The CDC reported on Tuesday that over 74 million people had been fully vaccinated with the Pfizer, Moderna, or Johnson & Johnson shot, accounting for 22.3% of the general adult population.

CVS A CVS corner drugstore is pictured. Photo: Justin Sullivan/Getty Images