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Method offers boost to safety profile of live vaccines

Weakening virus by amending genetic code promises route to large-scale production of live vaccines. 

Scientists have developed a method that could enable large-scale production of an effective flu vaccine for people with health conditions. 

The discovery could help produce industrial quantities of vaccines containing live viruses that have been weakened to induce immunity without causing infection – known as live attenuated viruses.  

These typically enable a speedy, lasting effect against illness, but represent a risk for some groups of people, such as the very young or very old. 

Researchers at the Roslin Institute, part of the Royal (Dick) School of Veterinary Studies, suggest the development could be used in combination with other methods of attenuation, or weakening, to enhance the safety profile of live virus vaccines. 

Virus recoding 

Researchers at the Roslin Institute developed their version of a vaccine for human flu by amending the virus’ genetic code in the lab.  

They changed letters into the RNA code – single-stranded genetic material – to add specific pairs that are known to make the virus vulnerable to attack from the human immune system. The resulting material contains live virus but will not trigger severe illness. 

Their experimental treatment was tested in mice, which after receiving a vaccine were able to survive exposure to a potentially lethal dose of flu virus. 

Researchers were able to produce large quantities of their vaccine in the growth mediums that are used to propagate live vaccines in industry – chicken eggs and canine kidney cells.  

Their method offers a realistic approach to produce vaccines in a commercially viable way, researchers say.  

It could be adapted to augment the production of existing live attenuated viruses to enhance their safety profile and render them suitable for use in at-risk individuals who currently cannot have vaccines of this type. 

Scientists hope to further investigate the biological processes at work using their method of attenuation, to better understand how the virus behaves and ensure it is used safely. 

The research was published in PLOS Pathogens and supported by the National Avian Research Facility at the Roslin Institute campus. 

Our approach has potential as a vaccine augmentation strategy – this method could be integrated into existing systems to incorporate multiple mechanisms to weaken the live virus contained in vaccines and boost their safety profile. It is a realistic, cost-effective way to amend existing vaccines of this type, for production at scale.

Dr Eleanor GauntRoslin Institute

Related links 

Scientific publication 

About the Royal (Dick) School of Veterinary Studies 

The Royal (Dick) School of Veterinary Studies is a one-of-a-kind centre of excellence in clinical activity, teaching and research. Our purpose-built campus, set against the backdrop of the beautiful Pentland Hills Regional Park, is home to more than 800 staff and almost 1400 students, all of whom contribute to our exceptional community ethos.

The School comprises:

The Roslin Institute

The Global Academy of Agriculture and Food Systems

The Roslin Innovation Centre

The Hospital for Small Animals

Equine Veterinary Services

Farm Animal Services

Easter Bush Pathology

The Jeanne Marchig International Centre for Animal Welfare Education

We represent the largest concentration of animal science-related expertise in Europe, impacting local, regional, national and international communities in terms of economic growth, the provision of clinical services and the advancement of scientific knowledge.  

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