While the duration of immunity after vaccination is being studied, booster vaccines could be needed, David Kessler, chief science officer for President Joe Biden’s COVID-19 response task force told a congressional committee meeting.
Le fa bokgoni jwa mmele jwa go itwela kgatlhanong le malwetse morago ga moento bo santse bo le ka fa tlase ga dipatlisiso, moento o mongwe mo godimo ga oo o ka tswa o tlhokega, David Kessler, Motlhankedimogolo wa saense wa setlhopha sa COVID-19 sa ga Moporesitente Joe Biden o boleletse Komiti ya khonkerese kwa kopanong.