Speaking at a press conference, the President of the Robert Koch Institute (RKI) said Omicron will take over as the dominant variant in Germany very soon.
Wieler said Covid cases in general have been declining “but unfortunately this is not a sign of an easing”.
“We have to get the still very high case numbers down,” he said, adding that a wave of infections was coming which threatens to overburden the health system.
In Germany, about 540 Omicron confirmed cases – and around 1,848 suspected cases – had been registered with the RKI so far. But most of this data is one to two weeks old, Wieler said.
“The trend is crystal clear: with numbers doubling roughly every three days, the new variant could account for the majority of all infection cases in our country in the next one, two, three weeks at the latest.”
He urged people to stay cautious over the holidays.
“Christmas must not be the spark that ignites the Omicron fire,” said Wieler. He therefore made an appeal to the population: “I urge you – spend Christmas in the smallest circle of the family.”
Health Minister Karl Lauterbach, of the Social Democrats (SPD), said there are now so many Omicron cases in Germany that “we have to assume that the Omicron wave can no longer be prevented”.
But Lauterbach stressed that Germany will be able to get the situation under control. The German government and states ordered fresh measures to come into force after Christmas, including limits on social gatherings.
“The measures we have taken are working,” he said.
The most important tool is a “particularly offensive” booster vaccination campaign, Lauterbach said.
The booster strategy will not prevent the wave, “but it is the most important thing that can be done to prevent many people from becoming seriously ill”, said the Health Minister.
Current studies show that booster vaccinations are effective at protecting against infections and severe illness caused by the Omicron strain of Covid-19.
In contrast to the second jab, the protective effect of the booster vaccination sets in after only one week, according to the studies.
When it comes to symptomatic infections, the effectiveness of booster jabs is “somewhere between 70 and 80 percent”, Lauterbach said, while the protection against getting severely ill is probably “above 90 per cent”, he said.
Earlier on Tuesday, the RKI had called for immediate tougher measures in Germany that included “maximum contact restrictions, maximum measures to protect against infection, maximum speed in vaccinating and reducing travel to what is absolutely necessary”.
The federal and state governments went against the call and the German media has subsequently reported a rift between the government and the RKI public health agency.
However, during the press conference Lauterbach said that the RKI is a “very important source”. He added: “We will work on communication.”
On Wednesday, the nationwide 7-day incidence was 289 Covid infections per 100,000 people. Health authorities in Germany reported 45,659 new Covid infections within the latest 24 hour period and there were 510 deaths.