Margaret Keenan is turning 91 next week. On December 8, 2020, at 6:31 GMT, she received the first publicly available Pfizer/BioNTech Covid-19 vaccine. "It's the best early birthday present I could wish for," Keenan stated. In the coming weeks, 800,000 doses of the vaccine will be given out to people over 80 years of age and healthcare workers, as part of a mass vaccination program -- the largest in UK history -- being rolled out across the United Kingdom. Up to four million doses are expected by the end of the month. After UK regulators fast-tracked approval last week that the vaccine is safe for public use, the UK became the first country to start using the Pfizer vaccine outside of clinical trials.