Gert van der Hoek
In Memoriam - Editor, Senior Moderator
Disclaimer: computertranslation
November 3, 2020
MFVM has requested SUM for a risk assessment in relation to human health, if mink breeders follow
killing of infected animals or fur in the 2020 season, mink production will continue into 2021
as normal. Only an assessment of risk is needed, not suggestions for possible solutions.
Summary
As of 2 November 2020, SARS-CoV-2 infection has been found on 191 mink farms. This development
has taken place despite intensive efforts by the authorities with regard to to limit infection.
At the same time, infection is seen with new types of SARS-CoV-2 virus that adapts to mink (mink variants) in
the local population, and there is a strong geographical and temporal correlation between numbers
positive mink farms and the incidence of infection among humans. Mink with SARS-CoV-2 makes a great
reservoir of virus, which is a major occupational risk associated with mink breeding in infected areas, and it
has not succeeded in limiting further spread to the surrounding community. Because of the
changes that occur in the spike protein in several of the mink variants of the virus, there is a risk that
vaccines targeting the spike protein will not provide optimal protection against the new viruses,
occurring in mink, and the immunity from past COVID-19 infection may provide less protection
against the new virus variants.
If mink production continues in Denmark, so that in 2021 a large one will be re-established
population of mink, it is considered highly probable that this population will be
susceptible to infection. In addition, SARS-CoV-2 is still expected to be in circulation among
people and no significant immunity in the population until the majority of the population is
vaccinated. Thus, there is a significant risk of recurrence of infection among mink and
people who have been seen in Western Denmark in 2020. This is considered to involve a great risk for
public health, both by causing greater disease burden among humans, and by a large
virus reservoir in mink increases the risk of recurrence of new virus mutations, which vaccines do not
provides optimal protection against. Overall, the flock immunity obtained by vaccination or
past infection, risk of being weakened or absent. At the same time, it must be expected to mean
a significant deterioration of our opportunities to maintain epidemic control in Denmark, which can
entail that one must introduce further restrictions and limitations on community life, etc.
Conclusion: A continued mink breeding during an ongoing COVID-19 epidemic involves one
significant risk to public health, including the possibilities for preventing COVID-19 with
vaccines.
Background
Since the beginning of June 2020, a total of 191 mink farms have been infected with SARS-CoV-2. These
is primarily located in the North Jutland Region and in Central and Western Jutland. Knowledge of introduction of
infection as well as consequences for infection between mink and human are primarily based on data from
North Jutland. In summary, it is probable that the introduction of infection with SARS-CoV2 to the first mink farm has taken place in connection with. human-to-mink infection in the weeks leading up to the outbreak.
Subsequently, in June 2020, there was a pronounced spread of infection to local communities in connection with outbreaks of a
nursing home, caused by a variant of SARS-CoV-2 developed among mink (hereinafter referred to as SARSCoV-2 mink variant). Since the beginning of August 2020, 168 mink farms have been infected in
Region North Jutland - all with SARS-CoV-2 mink variant. In parallel, it has been established
an increasing incidence of SARS-CoV-2 among citizens in the North Jutland Region, where now approx.
half is due to the SARS-CoV-2 mink variant (for details see Appendix 1).
Several mutations have occurred on an ongoing basis in the SARS-CoV-2 mink variant, where 5 clusters have so far been found.
In addition, two new SARS-CoV-2 types have been introduced in Esbjerg, respectively
and Vejle municipalities, which are not related to the mink variant.
Mutation in viruses
Virus mutations are small changes in virus genetic material that occur continuously in connection with that
virus copies itself. The more viruses that are copied, the more likely they are to occur
mutations. A virus's genetic material, and thus any mutations, can be uncovered by
whole genome sequencing (WGS). Several mink variants of SARS-CoV-2 have been seen
examples of changes in the spike protein. The spike protein is essential, taking humans after one
natural infection forms antibodies to the spike protein, and the potential COVID-19 vaccine
candidates are also based on this protein. Therefore, there is a risk that the effect of spike-based anti-COVID19 vaccines may be affected when changes occur in this part of the genetic material.
The presence of an extensive reservoir of virus in mink poses a serious threat to
public health, as viruses spread from animals to humans. The risk of mutations makes this risk
particularly serious. Mutations in the spike protein also occur in viruses in humans
worldwide) unrelated to mink farms, but not or very rarely the same mutations
which occurs in mink. However, it has been shown that the current vaccine candidates will be able to cover them
variations of viruses that have emerged among humans over the spring.
Concerns about changes in the spike protein in mink variants of SARS-CoV-2 were raised by the State
Serum Institute when the first mutations were detected. Among the mink varieties, seven have been seen
different mutations in the Spike protein and examples of up to 4 different changes in Spike
the protein in the same virus. A specific virus with 4 changes in the genes for spike protein has been detected in
five North Jutland mink farms and in 12 patient samples, of which 4 with direct connection to three of these
farm (cluster 5). Preliminary studies suggest that this virus exhibits decreased susceptibility to
neutralizing antibodies from several people with a history of infection. This is proven in a
laboratory experiments, where it is seen that the particular mink virus is not inhibited to the same extent in the growth of
antibodies from humans that have been infected with a non-mink-related variant of SARS-CoV2. Ongoing studies will further uncover the issue. Additional variants are identified by sequencing but not yet investigated for neutralization. This is worrying,
as it could potentially affect the efficacy of a future COVID-19 vaccine against infection
with new mink variants, and involve a risk of impaired immunity to these after over
COVID-19 infection, which is important for the individual and for herd immunity in society.
Significance for human health if mink production continues as normal
If mink production continues as normal, there will be a number of live mink after fur
left which is used as a breeding animal for next year's production. The number corresponds to approx. 20% of it
annual stock of approx. 17 million mink. In view of the current situation, this number will consist of 1)
mink not infected with SARS-CoV-2, 2) some mink which have probably formed
antibodies to SARS-CoV-2, as well as 3) presumably some mink that are unidentified infected with
SARS-CoV-2. The distribution of these groups is unknown. This means that in the coming months
after furs, outbreaks and the occurrence of SARS-CoV-2 infection can still be expected among
mink. Therefore, there will also continue to be a risk of infection from mink to humans.
In connection with the start of next year's breeding season, there will still be a risk of infection
SARS-CoV-2 among mink. Among mink that have not been exposed to SARS-CoV-2
all mink will be at risk of becoming infected. Among mink where there has been infection in the past
SARS-CoV-2 It is expected that some will have developed antibodies to SARS-CoV-2.
It is not known to what extent, -or for how long-, these antibodies protect against new infection with
SARS-CoV-2, and it is not known to what extent these antibodies will be passed on to
mink puppies. However, it is estimated that at the beginning of the newborn mink’s life there will be a protection from
maternal antibodies. However, this protection is assumed to decrease, so that after a few months
again will be a large population of mink without antibody protection against SARS-CoV-2.
So far, there are no signs that the infection in mink farms is decreasing over time. A continued presence
of SARS-CoV-2 in mink production, and the fact that the infection is typically detected late in the
some farms, will entail a risk of spread in relation to trade in breeding animals. In addition,
the risk depends on the prevalence of SARS-CoV-2 in humans at the time.
Both the onset of the first and second phases of the outbreak occurred at times of relatively low incidence
in the population and it is to be expected that further increase in population incidence will increase
the risk of introducing new virus types to mink from humans, as most recently seen in Esbjerg and
Vejle municipalities.
If mink production continues in Denmark, so that in 2021 a large one will be re-established
population of mink, it is considered highly probable that this population will be
susceptible to infection. In addition, SARS-CoV-2 is still expected to be in circulation among
people and no significant immunity in the population until the majority of the population is
vaccinated. Thus, there is a significant risk of recurrence of infection among mink and
people who have been seen in Western Denmark in 2020. This is considered to involve a great risk for
public health, both by causing greater disease burden among humans, and by a large
virus reservoir increases the risk of recurrence of new virus mutations that vaccines do not produce
optimal protection against. Overall, the flock immunity obtained by vaccination or
past infection, risk of being weakened or absent. At the same time, it must be expected to mean
a significant deterioration of our opportunities to maintain epidemic control in Denmark, which can
entail that one must introduce further restrictions and limitations on community life, etc.
November 3, 2020
MFVM has requested SUM for a risk assessment in relation to human health, if mink breeders follow
killing of infected animals or fur in the 2020 season, mink production will continue into 2021
as normal. Only an assessment of risk is needed, not suggestions for possible solutions.
Summary
As of 2 November 2020, SARS-CoV-2 infection has been found on 191 mink farms. This development
has taken place despite intensive efforts by the authorities with regard to to limit infection.
At the same time, infection is seen with new types of SARS-CoV-2 virus that adapts to mink (mink variants) in
the local population, and there is a strong geographical and temporal correlation between numbers
positive mink farms and the incidence of infection among humans. Mink with SARS-CoV-2 makes a great
reservoir of virus, which is a major occupational risk associated with mink breeding in infected areas, and it
has not succeeded in limiting further spread to the surrounding community. Because of the
changes that occur in the spike protein in several of the mink variants of the virus, there is a risk that
vaccines targeting the spike protein will not provide optimal protection against the new viruses,
occurring in mink, and the immunity from past COVID-19 infection may provide less protection
against the new virus variants.
If mink production continues in Denmark, so that in 2021 a large one will be re-established
population of mink, it is considered highly probable that this population will be
susceptible to infection. In addition, SARS-CoV-2 is still expected to be in circulation among
people and no significant immunity in the population until the majority of the population is
vaccinated. Thus, there is a significant risk of recurrence of infection among mink and
people who have been seen in Western Denmark in 2020. This is considered to involve a great risk for
public health, both by causing greater disease burden among humans, and by a large
virus reservoir in mink increases the risk of recurrence of new virus mutations, which vaccines do not
provides optimal protection against. Overall, the flock immunity obtained by vaccination or
past infection, risk of being weakened or absent. At the same time, it must be expected to mean
a significant deterioration of our opportunities to maintain epidemic control in Denmark, which can
entail that one must introduce further restrictions and limitations on community life, etc.
Conclusion: A continued mink breeding during an ongoing COVID-19 epidemic involves one
significant risk to public health, including the possibilities for preventing COVID-19 with
vaccines.
Background
Since the beginning of June 2020, a total of 191 mink farms have been infected with SARS-CoV-2. These
is primarily located in the North Jutland Region and in Central and Western Jutland. Knowledge of introduction of
infection as well as consequences for infection between mink and human are primarily based on data from
North Jutland. In summary, it is probable that the introduction of infection with SARS-CoV2 to the first mink farm has taken place in connection with. human-to-mink infection in the weeks leading up to the outbreak.
Subsequently, in June 2020, there was a pronounced spread of infection to local communities in connection with outbreaks of a
nursing home, caused by a variant of SARS-CoV-2 developed among mink (hereinafter referred to as SARSCoV-2 mink variant). Since the beginning of August 2020, 168 mink farms have been infected in
Region North Jutland - all with SARS-CoV-2 mink variant. In parallel, it has been established
an increasing incidence of SARS-CoV-2 among citizens in the North Jutland Region, where now approx.
half is due to the SARS-CoV-2 mink variant (for details see Appendix 1).
Several mutations have occurred on an ongoing basis in the SARS-CoV-2 mink variant, where 5 clusters have so far been found.
In addition, two new SARS-CoV-2 types have been introduced in Esbjerg, respectively
and Vejle municipalities, which are not related to the mink variant.
Mutation in viruses
Virus mutations are small changes in virus genetic material that occur continuously in connection with that
virus copies itself. The more viruses that are copied, the more likely they are to occur
mutations. A virus's genetic material, and thus any mutations, can be uncovered by
whole genome sequencing (WGS). Several mink variants of SARS-CoV-2 have been seen
examples of changes in the spike protein. The spike protein is essential, taking humans after one
natural infection forms antibodies to the spike protein, and the potential COVID-19 vaccine
candidates are also based on this protein. Therefore, there is a risk that the effect of spike-based anti-COVID19 vaccines may be affected when changes occur in this part of the genetic material.
The presence of an extensive reservoir of virus in mink poses a serious threat to
public health, as viruses spread from animals to humans. The risk of mutations makes this risk
particularly serious. Mutations in the spike protein also occur in viruses in humans
worldwide) unrelated to mink farms, but not or very rarely the same mutations
which occurs in mink. However, it has been shown that the current vaccine candidates will be able to cover them
variations of viruses that have emerged among humans over the spring.
Concerns about changes in the spike protein in mink variants of SARS-CoV-2 were raised by the State
Serum Institute when the first mutations were detected. Among the mink varieties, seven have been seen
different mutations in the Spike protein and examples of up to 4 different changes in Spike
the protein in the same virus. A specific virus with 4 changes in the genes for spike protein has been detected in
five North Jutland mink farms and in 12 patient samples, of which 4 with direct connection to three of these
farm (cluster 5). Preliminary studies suggest that this virus exhibits decreased susceptibility to
neutralizing antibodies from several people with a history of infection. This is proven in a
laboratory experiments, where it is seen that the particular mink virus is not inhibited to the same extent in the growth of
antibodies from humans that have been infected with a non-mink-related variant of SARS-CoV2. Ongoing studies will further uncover the issue. Additional variants are identified by sequencing but not yet investigated for neutralization. This is worrying,
as it could potentially affect the efficacy of a future COVID-19 vaccine against infection
with new mink variants, and involve a risk of impaired immunity to these after over
COVID-19 infection, which is important for the individual and for herd immunity in society.
Significance for human health if mink production continues as normal
If mink production continues as normal, there will be a number of live mink after fur
left which is used as a breeding animal for next year's production. The number corresponds to approx. 20% of it
annual stock of approx. 17 million mink. In view of the current situation, this number will consist of 1)
mink not infected with SARS-CoV-2, 2) some mink which have probably formed
antibodies to SARS-CoV-2, as well as 3) presumably some mink that are unidentified infected with
SARS-CoV-2. The distribution of these groups is unknown. This means that in the coming months
after furs, outbreaks and the occurrence of SARS-CoV-2 infection can still be expected among
mink. Therefore, there will also continue to be a risk of infection from mink to humans.
In connection with the start of next year's breeding season, there will still be a risk of infection
SARS-CoV-2 among mink. Among mink that have not been exposed to SARS-CoV-2
all mink will be at risk of becoming infected. Among mink where there has been infection in the past
SARS-CoV-2 It is expected that some will have developed antibodies to SARS-CoV-2.
It is not known to what extent, -or for how long-, these antibodies protect against new infection with
SARS-CoV-2, and it is not known to what extent these antibodies will be passed on to
mink puppies. However, it is estimated that at the beginning of the newborn mink’s life there will be a protection from
maternal antibodies. However, this protection is assumed to decrease, so that after a few months
again will be a large population of mink without antibody protection against SARS-CoV-2.
So far, there are no signs that the infection in mink farms is decreasing over time. A continued presence
of SARS-CoV-2 in mink production, and the fact that the infection is typically detected late in the
some farms, will entail a risk of spread in relation to trade in breeding animals. In addition,
the risk depends on the prevalence of SARS-CoV-2 in humans at the time.
Both the onset of the first and second phases of the outbreak occurred at times of relatively low incidence
in the population and it is to be expected that further increase in population incidence will increase
the risk of introducing new virus types to mink from humans, as most recently seen in Esbjerg and
Vejle municipalities.
If mink production continues in Denmark, so that in 2021 a large one will be re-established
population of mink, it is considered highly probable that this population will be
susceptible to infection. In addition, SARS-CoV-2 is still expected to be in circulation among
people and no significant immunity in the population until the majority of the population is
vaccinated. Thus, there is a significant risk of recurrence of infection among mink and
people who have been seen in Western Denmark in 2020. This is considered to involve a great risk for
public health, both by causing greater disease burden among humans, and by a large
virus reservoir increases the risk of recurrence of new virus mutations that vaccines do not produce
optimal protection against. Overall, the flock immunity obtained by vaccination or
past infection, risk of being weakened or absent. At the same time, it must be expected to mean
a significant deterioration of our opportunities to maintain epidemic control in Denmark, which can
entail that one must introduce further restrictions and limitations on community life, etc.