Major cryptocurrencies tumbled amid concerns about the omicron variant and holiday travel disruptions around the globe. Bitcoin BTCUSD, -1.67% traded 7.4% lower from 24 hours ago at around $47,849. The cryptocurrency was down more than 30% from its all-time high of $68,990 in November, according to CoinDesk data. Ether ETHUSD, -2.59% declined 7.6% over the past 24 hours, recently trading at $3,801. It was down more than 20% from its record high of $4,866 in November. For smaller tokens, Terra’s LUNA dropped 8.9% to about $86, while Polkadot DOTUSD, -2.64% went down 13% to around $28. Meme coin Dogecoin DOGEUSD, -3.00% traded 9% lower at around $0.17, while another dog-themed token Shiba Inu SHIBUSD, -3.26% lost 11.3% over the past 24 hours, recently trading at $0.000035.The omicron variant has led to the cancellation of thousands of flights around the globe, while the U.S. Centers for Disease Control and Prevention on Monday cut its recommended COVID-19 isolation time to five days from 10.