As European countries brace for a potential surge of coronavirus cases linked to the new variants, countries have reimposed strict lockdown measures, and some have made “medical” grade masks mandatory in some areas. Starting this week in Germany, N95 or surgical-grade masks are compulsory for people on public transportation, in office spaces and in shops. The higher-grade mask will also become mandatory in Austria, and France could follow, despite criticism that the more expensive N95 will be out of reach for many low-income earners. “We have to slow the spread of this variant. That means we cannot wait until the danger is palpable,” Chancellor Angela Merkel said. Effectively, the German authorities are trying to buy time by slowing the spread of the new variant long enough for the weather to warm and for the number of people vaccinated to increase, Ms. Merkel said.