“There’s no evidence right now that the general population needs a booster dose because we’re not seeing evidence of waning immunity or substantially reduced effectiveness against the Delta variant,” William Moss, executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health, said in an interview with Nightly... “I think for most people, outside those special populations, the immunocompromised and maybe the elderly — I think most people’s immunity is going to last years, to be honest,” Moss said. Moss said “years” is difficult to define, but if he had to guess, he would say three to four years, and maybe longer, before we need a booster. When it is time to roll out a new round of doses, Moss said he envisions it like the U.S.’s initial vaccine distribution — targeting the most vulnerable groups first like immunocompromised, elderly populations and health care workers. Then we may see a recommendation for the general public.