Reuters reported. Britain gave emergency use approval for the vaccine developed by Pfizer and BioNTech last week. “This coming week will be an historic moment as we begin vaccination against Covid-19," Matt Hancock, the U.K.’s health secretary, said in a statement. “We are doing everything we can to make sure we can overcome significant challenges to vaccinate care home residents."When will Britain start vaccinating?The first doses are set to be administered on Tuesday, with the National Health Service (NHS) giving top priority to vaccinating the over-80s, frontline healthcare workers and care home staff and residents.Britain has ordered 40 million dosesIn total, Britain has ordered 40 million doses - enough to vaccinate 20 million people.