Every year, the world enters an arms race with the flu. With the virus adapting constantly, scientists try to predict which strains will be the most prevalent in a given year and develop vaccines to fight those, but they don't always get it right. Creating a universal flu vaccine would give us the upper hand for the foreseeable future, and a new study from Oxford has identified a way to make that possible.
Picture a virus as a tiny ball covered in stalks. The heads of those stalks are the bits that let the virus cling to host cells, and deactivated versions of these proteins usually form the basis of each year's flu vaccines. Unfortunately they're also the bits that evolve the fastest, hence the annual need for new vaccines.
Targeting different sections of the virus could be the key to developing one vaccine to rule them all – or at least one that might not need to be updated every year. Previous studies have aimed for the more constant proteins found in the stalk sections or deeper inside the virus, or even targeted its DNA directly.
For the new study, scientists at Oxford have used mathematical models to get a better understanding of the evolutionary dynamics of the flu virus, in order to identify the sections (epitopes) that haven't changed much. Interestingly, they found some of these located in the normally highly-variable heads, and the team theorized that these epitopes would be the ones that the immune system naturally goes after.
Next, the team studied samples gathered from children in 2006 and 2007, and found that the viruses tended to recycle those epitopes over time. To test it out, the researchers took epitopes from flu strains from 2006 and 1977 and injected them into mice, and found that these protected the animals from infection by a strain from way back in 1934. This historic virus hasn't done the rounds in over 80 years, so there's no way the mice would have ever been directly exposed to it.
And if these epitopes can protect against flu strains past and present, the team says it should be applicable to future ones as well. While it's still fairly early stages, the research could be applied to developing a universal flu vaccine that might only need to be administered once. In future, the team says the approach could be applied to other viruses like the common cold or even HIV.
"I think this work serves a good example of how evolutionary models can have translational impact," says Sunetra Gupta, lead researcher on the study. "We have gone from a prediction of a mathematical model to a blueprint for a universal influenza vaccine. The outstanding teamwork coordinated by Dr (Craig) Thompson is what made it all possible."
In the meantime, we might not need to wait too long for other universal flu vaccines to hit the market – human trials were conducted in the UK last winter.
The research was published in the journal Nature Microbiology.
Source: Oxford University
