(CNN) The World Health Organization (WHO) has warned that social distancing measures will need to stay in place “for the rest of this year,” even as vaccination rollouts get under way globally, because it takes time to build up herd immunity.
WHO’s Chief Scientist Dr. Soumya Swaminathan said herd immunity — a situation where the majority of a population becomes immune to the virus either because they have become infected and recovered, or through vaccination — won’t be achieved this year.