The Belgian government reimposed some pandemic restrictions that it only relaxed a few weeks ago and expanded a nationwide use of the Covid-19 pass.
It follows infections and hospital admissions shooting upwards.
Daily infections in the European Union nation of 11 million increased 75% to reach 5,299 cases over the past last week.
Hospital admissions have increased 69% to reach 102 daily cases.
Deaths have increased slightly, with an average of 13 a day.
“As of Friday, there will be face masks in public places and they will be mandatory for staff of bars, restaurants and fitness clubs,” prime minister Alexander De Croo said.
“We need to raise our walls of protection.”
He added that the country’s Covid-19 pass will have to be shown to enter bars, restaurants and fitness clubs as of next week.
The passport shows you are either fully vaccinated, have had a recent negative test or have recently recovered from the disease.
Mr De Croo said the new moves still stopped well short of going into a lockdown.
He said because over 85% of Belgian adults are vaccinated, measures did not have to be as drastic as those previously in the pandemic.
“Last year, in a situation like this, we would be locking down certain activities,” he said.
“What we do today is keep everything open, using a vaccination passport or using masks.”
A complicating factor has emerged in the high virus transmission rate in Belgian primary schools.
The government research institute Sciensano found that more that one in four pupils there have antibodies to the virus.
Similar discussions about possibly increasing anti-virus measures are being held in the Netherlands, where the government is seeking advice from experts on whether it needs to reintroduce pandemic restrictions amid sharply rising infection rates.
The Netherlands has one of the fastest rising infection rates in Europe.
