The spread of COVID variants via mink farms could compromise the efficacy of a vaccine, according to a rapid risk assessment published by the European Centre for Disease Prevention and Control (ECDC) on Thursday (12 November).
Confirming that COVID-19 can spread between humans and minks, the EU disease centre warned that the virus may be able to accumulate mutations more quickly in minks which could then spread back into the human population.
They put this down to the large number of infections seen in mink farms, highlighting that once introduced to a mink farm, the virus can “spread quickly” between the animals.
They added that this could possibly due to biological differences between minks and humans.
Although they noted that there is currently “high uncertainty” regarding the nature of these mutations, the EU agency nonetheless warned that if these new COVID-19 variants, with lower susceptibility to neutralising antibodies, spread widely in the population, it could “potentially affect the level of overall vaccine effectiveness of vaccines under development”.
They also warned that the establishment of a “virus reservoir” among minks may give rise to problematic virus variants in the future.
The statement added that further investigations are required regarding the nature of these mutations and their implications for issues such as vaccine effectiveness, reinfections and spread and severity of the virus.
The agency said they are therefore closely monitoring the developments in Denmark in conjunction with the Danish public health authorities. Denmark said last week it would cull its mink population of up to 17 million after a mutation of the coronavirus found in the animals spread to humans.
Speaking at the unveiling of the EU’s health Union on Wednesday (11 November), which aims at increasing the range of preparedness tools to respond to future cross-border health threats, EU health Commissioner Stella Kyriakides reiterated that the situation in Denmark is being followed “extremely closely” despite it being a national competence.
She added that infection in minks has also been reported in other member states and in third countries.
Outlining their recommendations for dealing with the outbreak, the ECDC called on national authorities in EU/EEA and the UK to invest in extensive human and animal testing, including sequencing and characterising the antigenic properties and virus infectivity, to decrease the risk posed to the public.
They added that infection prevention and control measures for mink farm workers and visitors must be implemented, and that preparedness and response strategies that take both human and animal aspects into consideration must be implemented.
On 5 November, Denmark reported 214 COVID-19 cases infected with virus variants related to mink as well as infected mink on a number of mink farms. These variants have since been found in people living in the affected areas, who were found to be infected with strains showing four kinds of genetic changes in the virus.
[Edited by Zoran Radosavljevic]