MADRID/PRAGUE—The Czech Republic said on Monday it would allow critical workers such as doctors and teachers to go to work after a positive COVID-19 test, the latest European country to ease restrictions to keep services running as cases surge. As the much more contagious Omicron variant becomes dominant and forces hundreds of thousands to isolate, the pressure is growing on health workers, police, and firefighters, with teachers set to follow as schools resume after the Christmas holidays. But at the same time, data showing that Omicron is less likely to fill hospital beds, especially as many or most people are now vaccinated, has encouraged governments to scale back isolation measures and focus on sparing their battered economies. The hours of work lost to the pandemic around the world in 2020 were equivalent to 258 million full-time jobs disappearing, according to the International Labour Organisation (ILO), and last year the figure …