SUU, Alm.del - 2020-21 - Endeligt svar på spørgsmål 456: MFU spm. om ministeren kan bekræfte, at sundhedsmyndighederne har sikret sig, at der i internationale indrapporteringer om minkmutationer m.v. ikke fremgår, at der er fundet cluster-5-mutation på Sjælland, til sundheds- og ældreministeren

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WHO | SARS-CoV-2 mink-associated variant strain – Denmark

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Emergencies preparedness, response

SARS-CoV-2 mink-associated variant strain

– Denmark

Disease Outbreak News: Update

3 December 2020

Since June 2020, Danish authorities have reported an extensive spread

of SARS-CoV-2, the virus that causes COVID-19, on mink farms in

Denmark. On 5 November, the Danish public health authorities reported

the detection of a mink-associated SARS-CoV-2 variant with a

combination of mutations not previously observed (referred to as “Cluster

5”) in 12 human cases in North Jutland, detected from August to

September 2020.

To date, Statens Serum Institut (SSI) in Denmark has identified seven

unique mutations in the spike protein of SARS-CoV-2 among variants co-

circulating in mink and humans. SSI cultured the “Cluster 5” variant with

four amino acid changes in the spike protein, which was identified in

mink and isolated from the 12 human cases reported in North Jutland.

Preliminary findings suggested that there was a lower capability of

antibodies to neutralize the Cluster 5 strain, which requires further

investigation.

Following public health measures implemented by Danish authorities, the

incidence of COVID-19 in North Jutland decreased from 100 per 100,000

population in the week beginning 2 November (week 45) to 60 per

100,000 population in the week beginning 16 November (week 47). Over

the past weeks, Danish authorities have conducted mass testing of 111

447 individuals in North Jutland using reverse transcriptase polymerase

chain reaction (RT-PCR) and are planning to conduct genetic

sequencing for all positive samples.

In November 2020, 349 cases were reported among people associated

with mink farming, an increase from 200 cases in October 2020. Since

June 2020, a total of 644 people associated with mink farming have

tested positive. Furthermore, there have been at least 338 cases

reported among people working with mink pelting, in six factories and

two small facilities, which suggests that there is an increased risk of

COVID-19 infection in people who are involved in farming, culling and

pelting of mink. As of 1 December 2020, a total of 289 mink farms have

been affected, which accounts for approximately 20% of all mink farms in

Denmark.

https://www.who.int/csr/don/03-december-2020-mink-associated-sars-cov2-denmark/... 04-05-2021

SUU, Alm.del - 2020-21 - Endeligt svar på spørgsmål 456: MFU spm. om ministeren kan bekræfte, at sundhedsmyndighederne har sikret sig, at der i internationale indrapporteringer om minkmutationer m.v. ikke fremgår, at der er fundet cluster-5-mutation på Sjælland, til sundheds- og ældreministeren

WHO | SARS-CoV-2 mink-associated variant strain – Denmark

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From the week beginning 6 June 2020 (week 24) to the week beginning

16 November 2020 (week 47), 10 386 COVID-19 positive samples from

unique individuals underwent whole genome sequencing, which

accounted for 17.6% of all positive samples in the corresponding time

period. Of these sequenced samples, 750 were virus variants associated

with infected mink. In addition, at least two new SARS-CoV-2 variants

were recently detected in Southern Denmark which were not genetically

related to the original Danish mink-associated variant strain.

In North Denmark, the proportion of SARS-CoV-2 mink-associated

variant strains among all sequenced samples decreased from 60% and

51% in weeks 41 and 42, respectively, to 26% and 31% in weeks 46 and

47; in Central Denmark, the proportion increased from ~3% in weeks 41

and 42 to over 30% in weeks 46 and 47; in South Denmark, the

proportion increased from 0% in weeks 41 and 42 to 11% and 21% in

weeks 46 and 47, respectively, while noting that there are differences in

sequencing frequency and practices among various regions. In areas

with no affected mink farms, human cases infected with the mink-

associated variant have occurred sporadically. As of 20 November, no

new human cases of the Cluster 5 strain have been detected by genetic

sequencing, and authorities assessed that the Cluster 5 variant is no

longer circulating in humans.

Mink have previously been reported to be infected with SARS-CoV-2,

including in two outbreaks on large mink farms in the Netherlands in April

2020. Additionally, the Netherlands have reported human infections with

mink-associated SARS-CoV-2 strains which were not Cluster 5 strains.

To date, eight countries, namely Denmark, Lithuania, Netherlands,

Spain, Sweden, Italy, and Greece and the United States of America have

reported COVID-19 in farmed mink to the World Organisation for Animal

Health (OIE).

Public health response

On 4 November 2020, Denmark decided to cull all farmed mink in

Denmark. This decision was made following information that it had not

been possible to prevent the spread of infection from farm to farm, or

from animals to humans, and mink are acting as a reservoir and

contributing to the ongoing transmission in Denmark. On 5 November,

movement restrictions were introduced in the affected areas in North

Jutland. On 6 November, Denmark shared the full genome sequences of

SARS-CoV-2 obtained from humans to the Global Initiative on Sharing

Avian Influenza Data (GISAID) platform, and 133 sequences from mink

on 18 November. On 19 November 2020, restrictions were lifted in North

Jutland due to decreased incidence and the absence of new cases of the

Cluster 5 variant identified in the affected areas.

By 25 November, mink on all 289 affected mink farms, and farms within

an assigned zone, were culled. Additionally, mink farming has been

banned in Denmark until 31 December 2021, including import and export

of live mink. Economic support packages have been established for

those affected.

Danish authorities have continued to work with the WHO SARS-CoV-2

Virus Evolution Working Group and have agreed to share the Cluster 5

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WHO | SARS-CoV-2 mink-associated variant strain – Denmark

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variant SARS-CoV-2 with the COVID-19 Reference Laboratory Network

for further studies and testing.

WHO risk assessment

It is expected that all viruses, including SARS-CoV-2 change over time.

SARS-CoV-2 strains which are infecting mink and subsequently

transmitted back to humans, may have acquired unique mutations to

adapt to the mink host. Advanced laboratory studies are required to fully

understand the impact of novel variants of SARS-CoV-2 on viral

properties such as transmissibility, clinical presentation and effectiveness

of diagnostics, therapeutics and vaccines. These studies are long,

complex and are done in close collaboration with various research

groups.

While public health and social measures implemented by Denmark have

led to positive developments, recent findings of other mink-associated

variants among human cases in mid-Jutland and the detection of some

200 human cases among workers are of concern.

WHO advice

This event highlights the important role that farmed mink populations can

play in the on-going transmission of SARS-CoV-2 and the critical

importance of robust surveillance, sampling and sequencing of these

viruses by employing a One Health approach, especially around areas

where such animal reservoirs are identified. The global relevance of the

preliminary findings by Denmark is potentially significant, and WHO

recognizes the importance of prompt sharing of epidemiological,

virological, and full genome sequence information with other countries

and research teams, including through open-source platforms such as

GISAID.

WHO advises the following measures:

• Conduct further virological studies to understand the specific

mutations described by Denmark and to investigate any changes in

transmissibility and pathogenicity of the virus;

• Countries, particularly those with mink and other fur farming, to

increase the sequencing of SARS-CoV-2 from human and animal

samples where possible and share sequence data, including if the

same mutations are found;

• Countries to increase surveillance for COVID-19 at the animal-human

interface where susceptible animal reservoirs are identified, including

on mink and other fur farms;

• Countries to strengthen farming biosafety and biosecurity measures

around known animal reservoirs, particularly on mink farms, to limit

the risk of zoonotic events associated with SARS-CoV-2. This

includes infection prevention and control measures for animal

workers, farm visitors and those involved in animal husbandry or

culling;

• Remind communities and health workers of the basic principles to

reduce the risk of transmission of acute respiratory infections by:

•

Avoiding close contact with people suffering from acute

respiratory infections;

•

Washing hands frequently, especially after direct contact

with ill people or their environment;

•

Avoiding unprotected contact with farm or wild animals;

https://www.who.int/csr/don/03-december-2020-mink-associated-sars-cov2-denmark/... 04-05-2021

WHO | SARS-CoV-2 mink-associated variant strain – Denmark

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•

Practicing cough etiquette, such as maintaining distance,

covering coughs and sneezes with disposable tissues or

clothing, and washing hands, if experiencing symptoms of

acute respiratory infection;

Enhancing standard infection prevention and control

practices in health care facilities, especially in emergency

departments of hospitals.

WHO recommends the health measures listed above for all travelers. In

case of symptoms suggestive of acute respiratory illness either during or

after travel, travelers are encouraged to seek medical attention and

share their travel history with their health care provider. Health

authorities should work with travel, transport and tourism sectors to

provide travelers with information to reduce the general risk of acute

respiratory infections via travel health clinics, travel agencies,

conveyance operators and at points of entry.

WHO advises against the application of any travel or trade restrictions for

Denmark based on information currently available in relation to this

event.

For more information, see:

WHO Disease outbreak news SARS-CoV-2 mink-associated variant

strain – Denmark

WHO Coronavirus disease (COVID-19) pandemic

WHO COVID-19 Weekly Epidemiological Update and Weekly

Operational Update

WHO Health Topics page on COVID-19

WHO Scientific brief on the transmission of SARS-CoV-2: implications

for infection prevention precautions

WHO Public health considerations while resuming international travel

OIE Update 6 on the COVID-19 situation in mink in Denmark

OIE Technical factsheet, infection with SARS-CoV-2 in animal

OIE Questions and Answers on COVID-19

FAO Exposure of humans or animals to SARS-CoV-2 from wild,

livestock, companion and aquatic animals