"The current studies indicate something really good," Ralf Reintjes, professor of epidemiology at Hamburg University of Applied Sciences, told CNBC Thursday.
The highly contagious omicron variant can more easily infect vaccinated staff than previous strains, threatening to further exacerbate the worker shortage.
Union Square Hospitality Group will soon require customers to show proof of having received a Covid booster shot in order to dine indoors or drink at its bars.
Hong Kong needs to stick to its zero-Covid strategy until more people are vaccinate, said Yuen Kwok-yung, a member of the city's expert advisory panel.
Dr. Jeremy Faust, an instructor at Harvard Medical School, said that real-time data could be used to make targeted restrictions to slow the spread of Covid.