Home Science Covid-19 vaccines prove successful in pre-animal trial lab tests

Covid-19 vaccines prove successful in pre-animal trial lab tests

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Two possible vaccines to tackle Covid-19 in animals have proved successful in laboratory tests, scientists say. 

In-vitro trials have shown the two vaccine candidates, developed by UK-based firm The Vaccine Group, induced immunity at sites where the coronavirus replicates. 

The trials were conducted outside the animal – a process known as ‘in vitro’ – rather than in a live organism – known as ‘in vivo’. 

The company’s aim is to now develop vaccines that eliminate SARS-CoV-2, the virus that causes Covid-19, in living animals. 

The vaccines could be used to ensure cats and other pets do not become ‘a reservoir’ for future outbreaks. 

While the threat of catching Covid-19 from our pets is low, animals infected with coronavirus could lead to a second outbreak of the disease in humans, scientists say.

It follows reports of infected mink on fur farms in the Netherlands passing the virus on to human workers, leading to closures and culls.  

There is currently no coronavirus vaccine for humans and experts fear one won’t be ready until 2021, although there are multiple global efforts in progress. 

The new development from The Vaccine Group (TVG) means there could be a vaccine for cats and other pets before people.   

Dr Michael Jarvis at work in The Vaccine Group's labs. The University of Plymouth spinout company has revealed its first two possible vaccines have proved successful in pre-animal trial laboratory testing

Dr Michael Jarvis at work in The Vaccine Group’s labs. The University of Plymouth spinout company has revealed its first two possible vaccines have proved successful in pre-animal trial laboratory testing

‘Like all other human coronaviruses, SARS-CoV-2 emerged originally from animals,’ said Dr Michael Jarvis, associate professor in virology and immunology at the University of Plymouth and founder of TVG. 

‘There have already been a number of reported cases of human to animal transmissions of the virus and recently what appears to be the first evidence of animal to human transmission from mink. 

‘Although not from animal sources, the recent re-emergence of SARS-CoV-2 in Beijing underlines the importance of being able to control this virus for the long-term. 

‘The ability to control SARS-CoV-2 and prevent Covid-19 re-emerging from animal populations might become a key tool in the fight against this pandemic.’

The company is also investigating the longer-term potential of human vaccines and the next stage of development will assess the technique’s safety for use in humans, the company said in a statement.  

The Vaccine Group aims to now develop vaccines so as to eliminate SARS-CoV-2 (the virus that causes COVID-19) in existing animal sources

The Vaccine Group aims to now develop vaccines so as to eliminate SARS-CoV-2 (the virus that causes COVID-19) in existing animal sources

‘Whilst we are initially testing the efficacy of our vaccines in animals, positive data would open up the possibility of rapidly moving to a human vaccine,’ said Dr Jarvis. 

A vaccine works by training the immune system to recognise and combat pathogens, either viruses or bacteria. 

To do this, certain molecules – called ‘antigens’ – from the pathogen must be introduced into the body to trigger an immune response. 

By injecting these antigens into the body, the immune system can safely learn to recognise them as hostile invaders, produce antibodies and remember them for the future. 

If the bacteria or virus reappears, the immune system will recognise the antigens and attack them before the pathogen can spread and cause sickness.

TVG’s vaccines are based on safe forms of herpesviruses, which occur in nearly all animals including humans. 

The vaccines are created by inserting regions of the targeted pathogen DNA into the herpesvirus, which then stimulates an immune response against the disease when delivered into the animal. 

Scientists have made significant steps in the development of vaccines that could be used to tackle COVID-19 in animals

Scientists have made significant steps in the development of vaccines that could be used to tackle COVID-19 in animals

Testing found SARS-CoV-2 antigens were successfully incorporated in the company’s vaccine platform, meaning the vaccines should stimulate an immune response once in the target animal. 

The company’s current vaccine candidates are two of four for SARS-CoV-2 currently under development. 

Success with the first vaccine candidate was reached within eight weeks of the company first receiving antigen protein sequences.

‘In-vitro expression of the SARS-CoV-2 antigens demonstrates they have been successfully incorporated into TVG’s vaccine platform, meaning the vaccines should stimulate an immune response once in the target animal,’ the company said. 

‘Work is now underway preparing stocks of the first two candidates for animal trials.’    

The company is developing a range of vaccines to test different antigens and approaches to stimulating immunity.    

This is important as it is ‘still unclear’ which approaches to creating effective and long-term immunity will work in both animals and humans.        

‘It is impressive to see the speed with which the team has developed these vaccine candidates,’ said Matthew White at investor firm Frontier IP. 

‘Based on previous work with the same vaccine delivery platform we are hopeful that animal trials will demonstrate positive results.’ 

According to the British Veterinary Association (BVA), there is no evidence that pets can pass COVID-19 to their owners – in fact, humans pose more of a risk to cats than the other way round. 

The BVA suggested pets from infected households are more likely to carry the virus on their fur, through microscopic droplets that have been coughed or sneezed out by their human owner. 

BVA, the UK’s national body for veterinary surgeons, and other experts are keen to outline the distinction between cats carrying the virus on their fur, as opposed to being infected or showing symptoms themselves. 

The US Centers for Disease Control and Prevention (CDCP) says ‘there is no evidence that animals play a significant role in spreading the virus that causes COVID-19’, although it said ‘it appears the virus it can spread from people to animals in some situations’.  

This is despite the source of the current outbreak originally came from an animal, likely a bat, said CDCP, the US’s national public health institute. 

In a statement to MailOnline, TVG said that although animals may not be a route to ‘significant spreading’ of SARS-CoV-2, there is the potential for the virus to re-emerge at a later date from animals. 

‘Whilst human to human transmission is undoubtedly the primary route for spreading the virus, there have been incidents reported of animal to human transmission for example the recent reports of mink to human transmission on mink farms in the Netherlands. 

‘Ongoing re-emergence from an animal reservoir is a significant issue in other diseases such as Ebola and Lassa which continue to appear even though human to human transmission has been prevented.’ 

Scientists in China believe SARS-CoV-2 came from bats

The human COVID-19 SARS-CoV-2 virus split from its closest known relative – another coronavirus from a horseshoe bat (pictured) – about 30 to 40 years ago, according to University of Sydney Professor Simon Hothe jump to humans most likely happened more recently

The human COVID-19 SARS-CoV-2 virus split from its closest known relative – another coronavirus from a horseshoe bat (pictured) – about 30 to 40 years ago, according to University of Sydney Professor Simon Hothe jump to humans most likely happened more recently

Researchers at the Chinese Academy of Sciences, the People’s Liberation Army and Institut Pasteur of Shanghai came to the conclusion that the coronavirus may have come from bats.

In a statement, the team said: ‘The Wuhan coronavirus’ natural host could be bats… but between bats and humans there may be an unknown intermediate.

Research published in the Lancet also determined bats as the most probable original host of the virus after samples were taken from the lungs of nine patients in Wuhan.

The team suggested that bats passed the disease on to an ‘intermediate’ host which was at the Huanan seafood market in Wuhan before being passed on to the ‘terminal host’ — humans.

Authorities have pointed the blame on food markets in Wuhan, the Chinese city at the centre of the outbreak that scientists are scrambling to contain.

Rodents and bats among other animals are slaughtered and sold in traditional ‘wet markets’, which tourists flock to see the ‘real’ side of the country. 

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