https://www.siliconvalley.com/2021/04/15/update-2-u-s-preparing-for-1-year-covid-19-booster-shots-pfizer-chief-sees-need-3/ > April 15 (Reuters) – The United States is preparing for thepossibility that a booster shot will be needed between nine to12 months after people are initially vaccinated againstCOVID-19, a White House official said on Thursday. > While the duration of immunity after vaccination is beingstudied, booster vaccines could be needed, David Kessler, chiefscience officer for President Joe Biden’s COVID-19 response taskforce told a congressional committee meeting.