Israel began Monday offering anyone 60 and older a chance to get a fourth shot of a coronavirus vaccine, greatly expanding a double-booster effort that previously included just older residents with compromised immune systems and some health care workers.
The initiative puts Israel at the forefront of aggressive vaccination strategies as the omicron variant drives up infection rates around the world.
When officials launched the limited second-booster program last week, they said they were waiting for more data before making it more widely available. But within days, Prime Minister Naftali Bennett said the additional booster shot would be available to anyone 60 or older whose last dose was at least four months ago.
"Omicron is not delta," Bennett said at a late Sunday news conference. "It's a different ballgame altogether."
Expanding eligibility for the additional dose -- the fourth round of shots since vaccinations began a year ago -- is meant to protect the most vulnerable from the wave of positive cases that Bennett said could reach 50,000 a day within weeks in the small country.
Israel logged more than 6,500 cases Monday, the highest daily rate in months, according to Health Ministry figures.
More than 100 cities across the country are now operating under their strongest protocols, forcing some students back to remote learning if they have been exposed. Israeli epidemiologists said they expect the omicron variant, which appears to be more infectious but cause less serious illness, to hospitalize about 3 out of every 1,000 infected people.
Last week, the government rolled back some of its quarantine requirements for vaccinated people, fearing the rules could affect tens of thousands and lead to a de facto lockdown. Under new regulations, fully vaccinated people can avoid quarantine as soon as they test negative.
Critics have said research is still needed on whether a fourth dose will be effective. Some have argued that it would be better to focus on reaching the remaining vaccination holdouts.
About 6.4 million of Israel's 9.3 million residents have received a first shot, 5.8 million received a second dose and 4.1 million a third, according to the Health Ministry.
SCHOOLS IN EUROPE
Meanwhile, schoolchildren returned to classes Monday in parts of Europe, while the British government pledged to rush ventilation units and enough test kits to schools to ensure they can reopen this week despite soaring infection rates in the U.K.
Secondary school students in England also will be required to wear masks when they return to classes after the Christmas holidays and they could also face merged classes amid staffing shortages.
Prime Minister Boris Johnson said the mask guidance is intended to rein in transmission of the virus.
"We don't want to keep them. I don't like the idea of having face masks in [the] classroom any more than anybody else does, but we won't keep them on a day more than is necessary," he said.
British Education Secretary Nadhim Zahawi told Sky News: "The priority is to keep schools open."
He said testing, ventilation and other measures being put in place would "make a big difference to schools this year."
The omicron variant has caused Britain's daily new caseload to soar over Christmas and New Year's, with 157,758 infections reported for England and Scotland on Monday.
Patrick Roach, general secretary of the British teachers' union NASUWT, welcomed news that more ventilation units and testing kits would be available, but warned Sunday that the education industry has another pressing problem as schools prepare to reopen.
"The availability of teachers and support staff is also a key pressure point for schools this term as the number of covid cases continue to increase," Roach said.
Zahawi addressed the issue Monday, saying the government continues to monitor staff absences. He told Sky that absenteeism was around 8% last year.
"If that rises further, then we look at things like merging classes, teaching in bigger numbers," he said.
Children returned to class Monday in several parts of Germany, where patchy testing and reporting over the holiday period means the level of infections was somewhat uncertain.
In Berlin, one of the states where schools reopened, the local education minister said daily testing for children will be carried out this week. But Astrid-Sabine Busse told RBB Inforadio that plans call for that to be reduced to three tests per week after that.
Testing "is already an absolute routine at school before classes. And we want to keep it," she said.
In the eastern state of Thuringia, which had Germany's highest infection rate in recent weeks, children will start off the new term learning from home for at least two days. From Wednesday onward, schools will decide themselves whether to stick to online learning, bring children back to the classroom or work with a mixture of the two.
More than 12 million French children returned to school Monday with new rules. French children 6 years and older have been required to wear a mask in classrooms since November.
If a child tests positive, all other children in the class must test negative three times in the next four days to stay at school. The first antigen or PCR test must be performed by a health professional, followed by self-tests every two days, which are to be provided for free by pharmacies.
The move comes amid record-high infection numbers fueled by omicron, prompting a massive demand for self-tests across the country.
Pharmacists expressed concerns Monday over possible shortages caused by the new testing regimen unveiled Sunday.
The government is also encouraging local authorities in charge of financing public schools to buy carbon dioxide monitors that provide an alert when classrooms need to get ventilated.
Italian schools are not scheduled to reopen until next week, but already local leaders are mulling possible delays given the surge in cases.
The governor of southern Campania, Vincenzo De Luca, suggested Monday that a 20-30 day delay in the resumption of in-person schooling would allow for the next peak in cases -- expected by the end of this month -- to pass, while giving more time to increase vaccinations among students.
"It isn't an ideal measure, but it would allow us to resume in-person lessons quickly, with greater serenity for students, families and school staff," De Luca said.
It wasn't clear if his suggestion was a trial balloon or a real proposal.
Caretaker Dutch Education Minister Arie Slob said Monday that elementary and high school children will be allowed back into classrooms next Monday after a holiday that was extended to three weeks as part of a nationwide lockdown set to continue until Jan. 14.
Information for this article was contributed by Steve Hendrix of The Washington Post and by Mike Corder, Geir Moulson, Sylvie Corbet and Nicole Winfield of The Associated Press.