A group of new COVID-19 variants belonging to Omicron's JN.1 lineage, known as FLiRT, is spreading fast in the US. Experts say the symptoms remain largely consistent with other Omicron infections like sore throat, cough, fatigue, nasal congestion, runny nose, headache, muscle aches, fever, and potential loss of taste or smell. WHO has reclassified it as variant of interest.