Pfizer’s Covid-19 vaccine is pictured at Rady Children’s Hospital before it’s placed back in the refrigerator in San Diego, California on December 15, 2020.Adriana Drehsler | AFP | Getty ImagesU.S. officials said Wednesday they quarantined several thousand doses of Pfizer’s coronavirus vaccine in California and Alabama this week after an “anomaly” in the transportation process caused the storage temperature to get too cold.Pfizer’s vaccine, which was developed with German drugmaker BioNTech, requires a storage temperature of around minus 70 degrees Celsius. Vials of the vaccine are stored in trays, which carry a minimum of 975 doses each, according to the Centers for Disease Control and Prevention.Gen. Gustave Perna, who oversees logistics for President Donald Trump’s vaccine program Operation Warp Speed, told reporters that two trays of vaccine that arrived at two separate locations in California had to be returned to Pfizer after the temperature somehow fell to minus 92 degrees Celsius.The vaccine “never left the truck,” he said during a press briefing Wednesday. “We returned them immediately back to Pfizer and we sent immediate shipments to replace those two trays. We’re working with the FDA now, CDC, FDA and Pfizer to determine if that anomaly is safe or not, but we’re taking no chances and we can see that.”He said the “anomaly” happened again in Alabama.”All the way on the other side of the country in Alabama, two trays were received at one location. Same anomaly, went to minus 92. We were able to stop and quarantine the vaccine, stop and get a replacement shipment to Alabama,” he said.This is a developing story. Please check back for updates.