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Need for vigilance amid new 'Nimbus' COVID variant – DW – 06/25/2025
A new Omicron subvariant has caused infections and deaths in South and Southeast Asia. Europe may see a spike after population immunity fell over the winter.
What you need to know
European health authorities are warning there may be an increase in COVID-19 infections in the coming months amid the spread of the new Omicron variant NB.1.8.1. or "Nimbus."
"We have — what feels like — a fairly standard suite of recommendations that are being repeated," Ajibola Omokanye, an ECDC respiratory viruses expert, told DW.
"But we remain watchful."
The 2024-2025 winter in the Northern Hemisphere has given experts like Omokanye good reason to be watchful.
Population immunity against SARS-CoV-2, the virus that causes COVID-19, is down in Europe, probably due to fewer COVID cases over the winter.
As a result, Omokanye said there may be an increase in infections over the European summer. That may include severe cases that require treatment in hospital.
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SARS-CoV-2 is becoming more endemic in communities but it is "still not a season pathogen, like influenza," said Omokanye.
COVID still appears to move and mutate in unpredictable ways and that "stresses the need for continued vigilance and not being complacent about SARS-CoV-2,' said Omokanye.
"Just in the same way that we're not complacent about influenza or RSV."
Bangladesh has already seen deaths due to COVID in June. China and Singapore have also detected new cases of the respiratory disease.
Deaths in places like Bangladesh may be partly due to people's poor access to healthcare.
By comparison, Omokanye cited Canada, where Nimbus is dominant but without the same rates or severity of cases.
But it's not only a case of access to healthcare. "There are multiple factors. First, it's the timing of [a] variant's emergence," Omokanye said.
Another, he said, is that a there could be a greater possibility for waning immunity where there's been low circulation for a long period of time.
With vaccination, there are also several important factors: Which vaccines are available in each country or region and "who they are given to and when," said Omokanye.
"The question is: are the vaccines being taken up by that proportion of the population where you see the most severe disease?"
Similarly with healthcare systems and access to supportive treatment, because localized differences may determine how seriously infections progress in a population.
"They all contribute to the picture for severe disease," said Omokanye.
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ECDC and the World Health Organization have classified Nimbus as a Variant under Monitoring (VOM) due to two specific spike mutations.
The spikes are the "prongs" that enable the virus to latch onto and infect human cells. They have regularly mutated since SARS-CoV-2 first emerged.
Spike protein mutations reduce the ability of human antibodies to neutralize an infection and others that enhance the virus' ability to evade human antibodies.
VOM is the lowest category in a system where the more severe stages are Variant of Interest and Variant of Concern.
