Progress in the Battle Against Flu: The Quest for a Universal Vaccine
Each year, the flu affects approximately a billion people around the globe, leaving millions unable to work and causing between 290,000 to 650,000 deaths. The flu is a constantly changing virus, which is why individuals need to receive a new flu shot each year to stay protected. However, scientists are now working on a solution: a universal flu vaccine.
Why a Universal Flu Vaccine?
Current seasonal flu vaccines help prevent many deaths and serious illnesses annually. But their effectiveness can vary, typically reaching only about 60%. This is because the vaccine needs to match the specific strain of the flu virus circulating among humans, and this virus is always changing. But what if there was a vaccine that could protect against multiple strains of the flu and last for more than just a year? This is the question driving researchers around the world as they work on developing a universal flu vaccine.
There are currently about a dozen potential universal flu vaccines being tested in clinical trials, and many more in earlier stages of development. However, it's not going to happen overnight, as developing a universal flu vaccine poses a complex challenge.
The Flu Virus: A Moving Target
The term "flu" is somewhat misleading as it is not a single entity. It refers to various types of viruses that are always evolving, making it hard for human immune systems to keep up. The flu virus has proteins on its surface called haemagglutinin and neuraminidase, which our immune systems recognize and create antibodies to fight against. These proteins, however, are always changing, with 18 varieties of haemagglutinin and 11 of neuraminidase that can combine to create different flu subtypes. This is why it's so difficult to formulate the flu shot each year.
Improving the Accuracy of the Flu Shot
Some scientists are working on developing vaccines that target the parts of the virus that don't change. For example, one team is trying to stimulate an immune response against a specific section of the haemagglutinin protein on the influenza virus' surface. By introducing the body to haemagglutinin proteins with familiar bases but unfamiliar tops, the immune system focuses on the familiar portion and creates antibodies to fight it. This approach has shown promising results in early studies.
Other teams are working on different methods. One team created a vaccine that introduces the body to more than 80,000 variations of haemagglutinin, which overwhelms the immune system and forces it to focus on the fixed parts of the protein. Another team is developing a nasal spray that stimulates white blood cells in the lungs to be alert to any incoming infection.
Aiming for Universal Protection
Despite the different approaches, the goal is the same: to create a shot that protects against many different flu strains. Some flu viruses are already circulating in the human population and are largely responsible for the seasonal spikes in the disease that occur each year. When an entirely new version of the virus appears that is infectious enough, it can lead to a pandemic. A truly universal vaccine would offer "protection against any influenza A or B subtype, any strain, no matter if it's pandemic, zoonotic, or just a seasonal influenza virus," says one leading researcher.
However, creating such a vaccine is no easy task. It requires a lot of time, dedication, and funding. While some believe it is possible, it is a highly ambitious goal.
The Future of Flu Vaccination
A vaccine that you'd only need to get once and never have to think about again is still a long way off, if it's even possible. But that doesn't mean we can't make progress. One expert predicts that we could have an improved influenza vaccine in the next five to ten years.