Every year, millions of people wait in line for flu shots. Unfortunately, a flu shot in a given year will not protect everyone who gets it from getting the flu. In fact, last years vaccine was only 23% effective.
The best scientists can do when developing the vaccine is to make an educated guess at which strain will be the most common. The influenza virus is classified by the type of surface proteins it possesses. When you hear H1N1 for example, the H stands for haemagglutinin while the N stands for neuraminidase. Haemagglutinin is the key protein when developing flu vaccines. It is the protein that allows a virus to attach to the surface of our cells so other proteins can infect it and hijack its equipment to make copies of itself. Each season, scientists develop vaccines composed of a weakened or dead version of the virus so the body can make antibodies prior to being infected.
The trouble with the haemagglutinin protein on viruses is that the gene coding for it frequently mutates leaving several strains of influenza that a vaccine can’t protect against. This is why a flu shot is not always effective.
Previous studies have shown that the head of the haemagglutinin protein is prone to mutation while the stem is not. It rarely mutates into other forms so it is possible to create a vaccine for this portion of the protein. Because this part of the protein isn’t prone to mutation, a single vaccine could be completely effective against every strain.
In studies on several lab animals such as ferrets and mice, the vaccine was effective. While it is not a ‘universal vaccine’ yet, it is a good start. Tests were successful for several strains of H5N1 and H1N1.
The next step in developing the universal vaccine may be to test on a wider variety of flu strains and eventually to test on humans. The researchers don’t yet know whether it will be effective in humans. If scientists are successful in developing this vaccine, it could be end of annual flu shots.