Some vaccine doses kept too cold, Pfizer having manufacturing issues, U.S. officials say

FILE PHOTO: Nurse Mark Carey receives one of the first vaccinations at Mt. Sinai Hospital from Pfizer-BioNTech during the coronavirus disease (COVID-19) pandemic in the Manhattan borough of New York City, New York, U.S., December 15, 2020. REUTERS/Carlo Allegri

(Reuters) - The first days of Pfizer Inc's COVID-19 vaccine rollout have seen unexpected hitches including some vaccines being stored at excessively cold temperatures and Pfizer reporting potential challenges in its vaccine production, U.S. officials said on a Wednesday press call.

At least two trays of COVID-19 vaccine doses delivered in California needed to be replaced after their storage temperatures dipped below minus 80 Celsius (minus 112 Fahrenheit), U.S. Army General Gustave Perna said on the call. Pfizer's vaccines, made with partner BioNTech SE, are supposed to be kept at around minus 70C.