Video PlayerClose
![](139622670_16091111721831n.jpg)
A health worker receives a first dose of the Pfizer-BioNTech COVID-19 vaccine at the Santa Maria Hospital in Lisbon, Portugal, Dec. 27, 2020. (Photo by Pedro Fiuza/Xinhua)
A health worker receives a first dose of the Pfizer-BioNTech COVID-19 vaccine at the Santa Maria Hospital in Lisbon, Portugal, Dec. 27, 2020. (Photo by Pedro Fiuza/Xinhua)