The companies said preliminary laboratory studies demonstrated that three doses of the pfizer-biontech covid-19 vaccine neutralize the omicron variant, while two doses show significantly reduced neutralization titers.

Carnival Corporation & plc operates as a leisure travel company. Its ships visit approximately 700 ports. The stock was trading about 5.5% higher at $19.52 per share on Wednesday at the time of publication.

Royal Caribbean Cruises Ltd. operates as a cruise company worldwide. The stock was trading about 5.2% higher at $75.39 per share.

Norwegian Cruise Line Holdings Ltd., together with its subsidiaries, operates as a cruise company in the North America, Europe, the Asia-Pacific, and internationally. The stock was trading about 8% higher at $21.73 per share.