TY - JOUR T1 - Statement on the update of WHO’s working definitions and tracking system for SARS-CoV-2 variants of concern and variants of interest JF - Saudi Medical Journal JO - Saudi Med J SP - 427 LP - 427 VL - 44 IS - 4 A2 - , Y1 - 2023/04/01 UR - http://smj.org.sa/content/44/4/427.abstract N2 - ER -