Choice is good, but when it comes to protecting yourself against the flu, one vaccine that is able to fight off most virus strains year after year is far more appealing than an annual jab.
Now researchers from the Imperial College London are encouraged by results from their latest experiments on a universal flu vaccine approach that targets some of the influenza viruses’ core elements that remain unchanged each season. Using a “natural experiment” model, the scientists recruited 342 people at the beginning of the 2009 swine flu pandemic and collected their blood and nasal swab samples. When any of the patients developed flu symptoms, they sent another nasal swab to the researchers.
In their results, published in the journal Nature Medicine, the scientific team reported that the people who had the flu with only mild symptoms had higher levels of immune cells called CD8 T cells in their blood than those who were sicker. T cells include groups of immune system defenders that can recognize and bind to pathogens like influenza and other viruses, as well as engulf and destroy them. Most vaccines, including the flu shot, work by signalling the immune system to make hordes of antibodies against particular parts of a virus, which marks these pathogens for destruction. The massive size of the assault on the virus, however, comes at a price, since the virus can easily morph the proteins that these antibodies target and therefore evade death.
CD8 cells don’t have that problem, since they patrol for and recognize more conserved portions of viruses. But because they are more specialized, there aren’t as many of them in circulation. That makes them more durable as a vaccine target but also harder to generate in sufficient quantities to fend off an infection.
But the results show that CD8 could be a “blueprint for a vaccine,” as Ajit Lalvani, from the national Heart and Lung Institute at Imperial College said to BBC News.
For more information on other strategies for a universal vaccine, read TIME’s previous coverage, here.