![A healthcare worker prepares to administer the Pfizer-BioNTech vaccine, during the start of the COVID-19 vaccination campaign for those in higher risk categories, at a vaccine center in Overijse, Belgium on Thursday, Feb. 18, 2021.](https://www.gpb.org/sites/default/files/styles/flexheight/public/2021-09/covid_vaccine_ap21049403201107.jpg?itok=bufaM7DE)
Caption
A healthcare worker prepares to administer the Pfizer-BioNTech vaccine, during the start of the COVID-19 vaccination campaign for those in higher risk categories, at a vaccine center in Overijse, Belgium on Thursday, Feb. 18, 2021.
Credit: Eric Lalmand, AP