Fighting the spread of flu: Faster DNA sequencing means better vaccine development

Image copyright Shutterstock Image caption Improved strain tracking technology could make vaccine development easier

Thanks to advancements in DNA sequencing technology, development of new vaccines has become faster and cheaper.

It also makes it easier to test whether potential future vaccines will work in animals and humans.

But spotting a strain that could be difficult or impossible to identify in the wild is a much tougher job.

Unlike some historical forms of DNA sequencing, which can spend years to build up reliable data, scientists need only to do tiny chemical tweaks to the whole sequence – and a great deal of time.

Cradle-to-grave sequencing can start to reveal useful results much faster, and can provide information about the genetics of particular strains of the virus, and how well they attach to target cells.

Importantly, it can also measure how well a virus is specific to a particular target.

Image copyright Pixabay Image caption Coughing up something like human polio virus should not be too hard to spot

By tailoring the sequencing according to those data, it helps improve the probability of finding new or improved vaccines.

“What we are trying to do is bring that thing back that no one has ever actually seen before in a vaccine,” says Richard Morton from the UK’s Medical Research Council Laboratory of Molecular Biology.

While such viral strains can be identified years earlier if they are in stocks of vaccines, developing that specific strain in cells in the laboratory takes time.

“As viruses evolve and change, they have changes in their growth stages which make it much more difficult to differentiate a particular viral strain as ‘competition’ for the host’s resources,” explains Dr Morton.

By reworking the sequence, it will be easier to tell if a strain of that strain is particularly useful for the vaccines that are in production today.

Image copyright Pixabay Image caption A strain of flu has already been developed that has different genes for different members of its lethal range

If they are more advantageous, that means the company developing it will be able to engineer that strain into a form that will be good for vaccinating against current strains.

It also means even less strain is needed. “This new understanding means we can produce a whole sequence for them much more quickly and at a much lower cost,” he says.

Enlarge Image Image copyright CMO and d-face/Network of Technology-driven Broad Innovation and Entrepreneurship

Not only has it reduced the time involved in developing any vaccine from years to weeks, it means that there is potentially no virus out there that can evade detection.

“The increased speed of genome sequence creates the possibility that we may find very early exposure of new influenza strains, for the first time,” says Dr Morton.

“But this does not mean that we know which viruses are out there, or will work in humans. Only time will tell.”

But the ability to detect new strains of viruses could make the development process more efficient.

For example, say scientists believe a new influenza strain has a significantly bigger impact on the human population than existing strains of the virus, they can look for only one strain that is related to that strain, and combine it with the genome of the existing virus so that it can produce a new vaccine against that strain, and other strains, in about three weeks.

Image copyright AFP Image caption The insertion of new and improved flu virus sequence information into a protein not affected by immune response is quite a tricky and complex task, and must use a very precise dose

Image copyright csp Image caption Now the trouble is to insert the sequence into a protein not affected by the immune response. In the 1918 influenza pandemic, the resistant virus made up 5.5% of the world’s total circulating virus

Given the spread of global flu in the twentieth century, any ability to contain the virus in a single form with high ease has potential to affect millions and billions of people every year.

“It’s certainly a threat and it is difficult to predict if it will become a disease, and it will fall in the similar leagues with HIV and malaria,” Dr Morton tells us.

“From a human aspect, and in terms of the ability to control it, it is likely to become a huge problem.”

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