Winter weather impacting COVID-19 vaccine shipments across U.S.

Winter storms have impacted deliveries of coronavirus vaccines in all 50 states. Several vaccination sites have had to close due to a lack of doses. This comes as a new study raises questions about how many doses of the Pfizer vaccine are actually needed. Dr. Amesh Adalja, an infectious disease expert and senior scholar at Johns Hopkins University's Bloomberg School of Public Health, joined CBSN with the latest on the nation's vaccination efforts.