Coronavirus: Mink strain ‘should not pose threat to success of Covid-19 vaccines’, Dr Fauci says

A new mutation of coronavirus that has spread from minks to humans should not pose a threat to the success of a vaccine, the United States’ top infectious disease official has said.

The discovery of the new strain in Denmark triggered a culling of millions of farmed mink and led the UK to ban non-native arrivals from the Nordic country, after its prime minister Mette Frederiksen warned the development posed “a serious risk to public health and to the development of a vaccine”.

The genetic change in the mutation – which has infected at least 200 people – is in the spike protein of the virus, which is a key target for vaccines, Danish scientists have said.

But Dr Anthony Fauci, viewed by many as Donald Trump’s embattled counterweight throughout the pandemic, said that although the issue should be taken seriously, “at first cut, it doesn't look like something that's going to be a really big problem for the vaccines that are currently being used to induce an immune response”.

Dr Fauci said his team of experts at the US’s vaccine research centre have taken “a first look” at the strain.

“When you look at the binding sites [on the spike protein] … it does not appear at this point that the mutation that has been identified in the minks is going to have an impact on vaccines and the effect of vaccine-induced immune response,” he said in a discussion broadcast by the Chatham House think-tank.

But, he added, chiming with early warnings cited by the Danish PM that the new strain could weaken humans’ antibody response: “It might have an impact on a certain [number] of the monoclonal antibodies that are developed against the virus – we don't know that yet.”

A similarly optimistic outlook was proffered by scientists working on a potential vaccine candidate at Denmark's State Serum Institute (SSI).

Early animal trials of their vaccine found it to be effective in preventing against the mink-related strain, which is known as Cluster 5.

“We couldn't resist testing the rabbit antibodies we have against Cluster 5, and it works,” Anders Fomsgaard of SSI said on Thursday.

The vaccine candidate, which is in early stages of development, will soon move to human trials, during which it is uncertain if it will have the same effect.

“Whether this also applies to other vaccines and whether it applies to human antibodies, we do not know,” Mr Fomsgaard told Danish broadcaster DR.

It came as the European Centre for Disease Prevention and Control issued new guidance to curb the spread of the virus between minks and humans, warning large numbers of animal infections risk the virus accumulating mutations more quickly and spreading back into the human population.

But Dr David Heymann, a former WHO assistant director-general and Public Health England chair, said it would be unlikely for a mutated strain of the coronavirus from the minks in Denmark to change the course of the pandemic.

"This virus is in every country and it's mutating differently in every country," Dr Heymann during the briefing at Chatham House, where he is a distinguished fellow in global health. 

“In order for this virus from the minks to be able to replace virus in other countries and impact on vaccines, it would have to be more fit than the other viruses that are around now and spread easier, more rapidly and replace those viruses in other countries.”

Sage member Sir Jeremy Farrar warned the mink mutation was a “canary in the coal mine” for Sars-CoV-2 becoming an endemic animal virus, which could “easily get established in other animal populations such as rats, mice, ferrets and voles” before spreading back to humans in new forms “as a revolving door” in the years to come.

“The reason why this is so worrying is it shows how promiscuous this virus is and that it is very able to leap from certainly bats and then probably some intermediate host in China at some point in 2019 and come across [to] the humans,” the Wellcome Trust director said.

“And what the minks demonstrate to us and reminds us of – is that it can go back the other way … That's the worry of the mink story, rather than the minks themselves.”

Sir Jeremy said he thought “epidemics are the horrible poster child of the things we're going to face in the 21st century”, adding that they would not be “national” issues, given the drivers include changes in climate, animal and human behaviour, trade and travel.

But, he suggested that the Covid-19 pandemic had shown the need for international cooperation and collaboration and had broken “the abyss of nationalism” growing over the past decade.

“Humanity has looked at itself and said we have to work together as a world and I think the scientists around the world have actually driven that through Covid - they've worked, they've collaborated, they've shared their information and I think that is to be applauded and and shows us a way through,” he said.

Additional reporting by agencies