It’s that time of year again: Roll up your sleeve, get dabbed with alcohol-soaked cotton balls, and feel the prick of the needle. But the annual flu shot may soon be a thing of the past thanks to scientists at the Imperial College London’s National Heart and Lung Institute.
Led by Professor Ajit Lalvani, chair of infectious diseases, the study found that a certain type of T cells in the immune system may protect against flu symptoms. These cells attack the core of the virus which cannot mutate, meaning it may be possible to design a one-time, universal flu shot, according to an article in Science Daily.
To create traditional flu vaccines, researchers attempt to predict which strains of influenza will be most prevalent each year. They then develop vaccines to stimulate the immune system to produce a large amount of antibodies that recognize and attack proteins on the surface of the virus.
But if someone is exposed to a different strain, the vaccine will do nothing to protect against it. Even when experts predict the right strain, the protection is not always effective. According to theCenters for Disease Control and Prevention (CDC),last year the vaccine proved only 56 percent effective for all age groups.
The problem is that viruses easily mutate, rendering the antibodies ineffective and requiring a new vaccine every year. The flu virus can also infect a variety of hosts, including humans, birds, and swine, and may mutate as it is transmitted between groups.
For the new Imperial College London study, researchers recruited 342 people at the beginning of the 2009 swine flu pandemic, collected their blood samples, and sent them home with nasal swabs. When any of the patients developed flu symptoms, they sent a nasal swab to the researchers. The scientific team reported that the people who had the flu with only mild symptoms had higher levels of immune T cells known as CD8 in their blood prior to becoming ill. Those with worse symptoms had lower levels of CD8. Previously, experimental models had suggested that T cells might protect against flu symptoms but until now, the idea had not been tested in humans during a pandemic.
CD8 T cells skirt the problem of virus mutations because they attack the core of the virus, and researchers already know how to stimulate the immune system to make CD8 T cells by vaccination. Now that they understand their protective function, researchers hope to design the first universal flu shot, putting an end to the annual fall ritual.