The international public health body said it was monitoring the mutation, which was a “concern,” but that it was too early to tell if it posed any risk to humans or would undo the impact of a potential vaccine.
“These types of things happen, this is a global pandemic and many millions of people have been infected, many millions of animals have been exposed,” said WHO head of emergencies program Mike Ryan, during a virtual press conference from Geneva.
“Right now, the evidence that we have doesn’t suggest that this variant is in any way different in the way it behaves…it is still the same virus.”
On Thursday, Denmark announced strict new lockdown measures in its northern counties, home to most mink farms, after authorities discovered the mutated strain in the region.
The government said on Wednesday it would cull all minks — up to 17 million — to prevent human contagion with the mutated coronavirus, which health authorities said could be more resistant to future vaccines.
Ryan said mammal species like mink were “very good hosts” but that health officials were still a “long, long way away” from any determination on the mutation’s impact on a vaccine.
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The WHO also said it was looking at biosecurity in other countries that farm mink to “prevent spillover events,” said Maria van Kerkhove, the WHO’s technical lead for Covid-19, adding that the risk from other farm animals and livestock was generally low.
“Mutations are normal,” van Kerkhove said. “These types of changes in the virus are something we’ve been tracking since the beginning.”
Denmark’s State Serum Institute (SSI), the authority dealing with infectious diseases, said the strain of the mutated coronavirus that prompted the mink cull, had been found in 12 people and on five mink farms so far.
In a report published on Wednesday, the SSI said laboratory tests showed the new strain had mutations on its so-called spike protein, which invades and infects healthy cells. That poses a risk to future Covid-19 vaccines, which are based on disabling the spike protein, it said.
In the United States, nearly 10,000 minks at nine fur farms in Utah died of Covid-19, state veterinarian Dean Taylor told NBC News last month.
The deaths forced the affected farms to quarantine as the outbreaks were investigated.
The Associated Press and Reuters contributed to this report.
Minyvonne Burke contributed.