Austria has become the first European country to announce it is making coronavirus vaccines mandatory as health data from the United Kingdom indicated COVID-19 infection rates were dropping.
Austria's vaccine requirement will be implemented in February, officials said.
Administrative penalties will be imposed for violations of the mandatory vaccination rule, Chancellor Alexander Schallenberg said.
Details of the regulation are to be hammered out in the coming weeks.
Preparing the way for that, the country will return to lockdown on Monday, which will last at least 10 days for everyone, and perhaps longer for those who are not vaccinated when it ends.
The country is suffering from a severe fourth wave, with the seven-day incidence per 100,000 inhabitants at 1000.
Hospitals are running out of capacity to care for patients, especially in areas like Salzburg and Upper Austria, where incidence rates are hovering above 1,500.
Schallenberg said that a new lockdown would "hurt enormously," but that it was necessary.
"We don't want a fifth wave, we don't want a sixth and seventh wave," he said.
He called the step a hard one to take, adding "it hurts a lot".
Schallenberg and other members of the government have until recently resisted calls for night-time curfews but seem to have changed their minds after several states said they were going ahead with lockdowns on their own initiative.
The mandate and lockdown decisions infuriated many in a country where scepticism about state mandates affecting individual freedoms runs high and is encouraged by the populist Freedom Party, the third biggest in parliament.
Party leader Herbert Kickl posted a picture on Facebook with the inscription: "As of today Austria is a dictatorship."
The party is planning a protest on Saturday but Kickl cannot attend because he has tested positive for COVID-19.
Roughly two-thirds of those eligible in Austria are fully vaccinated against COVID-19, one of the lowest rates in western Europe.
Its infections are among the highest in Europe, with a seven-day incidence of 991 per 100,000 people.
People will only be allowed to leave their homes for urgent shopping or errands, to go to work or for outdoor exercise while pubs and most shops will close.
Meanwhile, new figures indicate coronavirus infections have fallen in most parts of the UK.
The prevalence of COVID-19 infections in England fell back to about one in 65 people in the week ending November 13, the Office for National Statistics said on Friday.
It was a drop in cases for a second week after hitting its highest level of the year.
Prevalence had been one in 60 people in the previous week.
Recorded cases and estimated prevalence of infection have both dropped back from peaks hit before a school half-term holiday at the end of last month.
Wales also registered a drop, with one in 55 people estimated to have had COVID-19 in the week to November 13, down from one in 45 the previous week.
with Reuters and PA