COVID-19 variants called 'FLiRT' continue to spread across the US, CDC says KSAT San AntonioNew COVID variant 'FLiRT': What to know about spread, symptoms USA TODAYDoctors Warn About 2 New COVID Variants—What to Know About 'FLiRT' Strains Prevention MagazineFLiRT, New Covid-19 Variant In US: What We Know So Far NDTV