i m so filled with emotion about what just happened. i just it s extraordinary. reporter: an inspiring reminder of what the future holds. i did it, america! reporter: we reflect on a year dominated by vaccines and hope 2022 offers a shot at something even better. wow. what a year. and you can t talk about 2021 without mentioning the global fight against covid and the huge medical breakthrough that was the distribution of covid vaccines, the shots created, evaluated, and authorized in just months was a first for vaccine development. millions around the world lined up to get their shots and then months later lined up again for a booster. but it wasn t without controversy. let s take a look back. reporter: this morning, a graim grim new national record, more than 4,000 covid deaths