Compared to those who were unvaccinated, fewer people were infected with Covid-19 and even when they were infected, they were less likely to show symptoms.
At least two million people will be vaccinated against Covid-19 every week, ministers have said in plans for the biggest vaccination programme in UK history.
In January 2020, China reported the first known death from Covid-19. From an unknown illness to a deadly pandemic - how did we get here?