Danish mink coronavirus data ‘do not support’ fears over reduced vaccine effects

A mutation of the coronavirus detected in Danish mink and passed back to humans is not likely to reduce the efficacy of a potential Covid-19 vaccine as previously feared, experts have said following a review of published data.

Danish mink coronavirus data 'do not support' fears over reduced vaccine effects
People attend a Covid-19 testing centre in Frederikshavn. Photo: Claus Bjørn Larsen/Ritzau Scanpix

A series of experts have said they found no clear cause for concern that a vaccine would be less effective against the cluster 5 variant of coronavirus, which has been found in Danish minks.

Denmark’s government has applied tight restrictions in North Jutland and initiated a politically fraught decision to cull every fur farm mink in the country due to concerns that a mutated form of coronavirus originating in mink could set back vaccine research.

The decisions were based on the preliminary results of testing on a variant of the mutated coronavirus known as ‘cluster 5’, conducted by the country’s national infectious disease agency State Serum Institute (SSI).

But after SSI released a paper on its research, experts have cast doubt as to whether the mutation would have any effect on vaccine efficacy, Danish media including DR and Information report.

The SSI paper details tests conducted by the institute on the variant, which has been detected in 12 confirmed cases in humans in Denmark.

Experts told Danish media that the report did not give them initial cause for serious alarm.

“The data that have been released do not support (the claim) that this is a risk for vaccines not working,” Jen Lundgren, professor of the infectious disease department at Copenhagen’s Rigshospitalet, told DR.

A similar assessment was made by virology professor Søren Riis Paludan of Aarhus University.

“Based on the data they get, I don’t think you can conclude – and almost not even speculate – that this could be the breeding ground of a new pandemic or that the vaccines won’t work,” Paludan told DR.

Thomas Laustsen, professor of Immunology and Microbiology at the University of Copenhagen said there was no conclusive evidence in the paper of a dangerous mutation.

“With the data SSI has released, it’s very difficult to say whether this is a very dangerous mutation. We don’t actually know whether we have a problem,” Laustsen told the broadcaster.

“I can understand that eyebrows were raised when you could see in the laboratory that antibodies didn’t work as well on this mutation. But with the data I’ve seen now, there’s nothing here that makes me tremendously worried,” he added.

A fourth expert also told DR that he was not concerned over vaccine effectiveness, after having consulted the SSI paper.

“I don’t think, based on this paper, that you can say future vaccines would be ineffective or have reduced function with regard to the cluster 5 variant,” Aarhus University Hospital professor and senior consultant doctor Lars Østergaard said.

Although less sensitive than other variants, the cluster 5 variant remains sensitive to antibodies, Lundgren said to DR.

That appears to be in some contrast with an explanation previously given by SSI officials.

Five different mink-specific variants of mutated coronavirus have been discovered, of which one – ‘cluster 5' – showed a change in spike proteins on the virus.

This gave rise to concerns relating to vaccine efficacy because many of the vaccines in development are targeted towards the spike proteins on the regular coronavirus.

“What we could see was that this variant showed less sensitivity to… neutralising antibodies from recovered patients,” Tyra Grove Krause, SSI’s head of department for infectious disease epidemiology and prevention, said at a briefing last week.

“This is a concern because this may mean that in the future that some of the Covid-19 spike-directed vaccines may be less effective against this variant of the virus,” she said.

“This is not certain. We still need to do ongoing tests and research, but it's a concern,” she noted.

But the cluster 5 variant does in fact react to high levels of antibodies, according to Lundgren’s comments to DR.

“It depends on the level you expose the virus to with these antibodies; if there are very few antibodies there might be a problem, but if there are relatively many antibodies the possible problem is cancelled out, and that’s what vaccines are meant to do. They are meant to deliver many antibodies,” he said.

“These data do not support this being a threat to the vaccines,” he added.

Member comments

  1. The local should tread carefully when reporting against an agency findings . A few “experts “ opinions does not make the SSI report invalid or untrue . I can throw a rock at any group of “experts” and find a different answer each time I throw it .

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IN NUMBERS: Has the Omicron Covid-19 wave peaked in Denmark?

The number of new Covid-19 infections fell on Saturday for the second day in a row, following a three-day plateau at the start of last week. Has the omicron wave peaked?

IN NUMBERS: Has the Omicron Covid-19 wave peaked in Denmark?
Graffiti in the Copenhagen hippy enclave of Christiania complaining of Omicron's impact on Christmas. Photo: Philip Davali/Scanpix

How many cases, hospitalisations and deaths are there in Denmark? 

Denmark registered 12,588 new cases in the 24 hours leading up to 2pm on Saturday, down from the 18,261 registered on in the day leading up to Friday at 2pm, which was itself a decline from the record 28,283 cases recorded on Wednesday. 

The cases were identified by a total of 174,517 PCR tests, bringing the positive percentage to 7.21 percent, down from the sky high rates of close to 12 percent seen in the first few days of January. 

The number of cases over the past seven days is lower than the week before in almost every municipality in Denmark, with only Vallensbæk, Aarhus, Holseterbro, Skanderborg, Hjørring, Vordingborg,  Ringkøbing, Kolding, Assens, Horsens, Thisted, and Langeland reporting rises. 

Hospitalisations have also started to fall, with some 730 patients being treated for Covid-10 on Saturday, down from 755 on Friday. On Tuesday, 794 were being treated for Covid-19 in Danish hospitals, the highest number since the peak of the 2020-21 winter wave.

The only marker which has not yet started to fall is the number of deaths, which tends to trail infections and hospitalisations. 

In the 24 hours leading up to 2pm on Saturday, Denmark registered 28 deaths with Covid-19, the highest daily number recorded since 20 January 2021, when 29 people died with Covid-19 (although Denmark’s deadliest day was the 19 January 2021, when 39 people died). 

How does Denmark compare to other countries in Europe? 

Over the last seven days, Denmark has had the highest Covid-19 case rate of any country in Europe bar Ireland. The number of new infections in the country has climbed steadily since the start of December, apart from a brief fall over Christmas. 

So does this mean the omicron wave has peaked? 

Maybe, although experts are not sure. 

“Of course, you can hope for that, but I’m not sure that is the case,” said Christian Wejse, head of the Department for Infectious Diseases at Aarhus University Hospital. “I think it is too early to conclude that the epidemic has peaked.”

He said that patients with the Omicron variant were being discharged more rapidly on average than had been the case with those who had the more dangerous Delta variant. 

“Many admissions are relatively short-lived, thankfully. This is because many do not become that il, and are largely hospitalized because they are suffering with something else. And if they are stable and do not need oxygen, then they are quickly discharged again.” 

Denmark’s Prime Minister Mette Frederiksen said during a visit to an event held by the Social Liberal party that the latest numbers made her even more optimistic about the coming month. 

“We have lower infection numbers and the number of hospitalisations is also plateauing,” she said. “I think we’re going to get through this winter pretty well, even if it will be a difficult time for a lot of people, and we are beginning to see the spring ahead of us, so I’m actually very optimistic.” 

She said that she had been encouraged by the fact that Omicron was a “visibly less dangerous variant if it is not allowed to explode.”