Covid-19 booster vaccines: What we know and who’s doing what

Covid-19 booster vaccines: What we know and who's doing whatThe virulence of the delta variant has prompted many countries to start administering booster vaccines.Elisabeth Mahase looks at what is happening where Elisabeth Mahase Do we need booster doses?How long does immunity after covid-19 vaccination last?It's something everyone would like to know, but it's a question that can't currently be answered with certainty.