Every October signs to remind you to get your annual flu shot pop up in your local drug store. Each year new vaccine becomes available to offer protection against the seasonal flu bug. The influenza virus is very good at adapting from year to year, making the previous year's vaccine obsolete. Because each new year brings a slightly different virus and a slightly different vaccine, you need to get your flu shot each year to prevent infection. However, a new type of flu vaccine is in the works, and it may eliminate the idea of an annual flu shot.
Vaccines are designed to show your immune system particular germ characteristics . Once your body recognizes these characteristics as foreign, it can recognize the real thing when being invaded by an actual germ. The characteristics that are normally targeted for vaccine production are present on the surface of the virus or bacterium. This is because if the characteristic is on the surface, then it will be easily identified by your immune system. The only problem is that these are the characteristics that evolve the fastest in viruses and bacteria. Therefore, the vaccine for last year's flu is now out of date because the virus has changed. Your body can't identify this year's virus because its surface characteristics are different, so it looks different to your cells.
There are other characteristics that do not change as rapidly, which are the targets for universal vaccines. A closer look at how we actually respond to flu virus infection showed that our immune cells can respond to more than surface characteristics. T-cells, a type of white blood cell capable of killing viruses, are able to recognize characteristics associated with internal viral structures. Because these internal characteristics evolve more slowly, they are also more common among various flu viruses. A universal vaccine would provide protection for more types of flu virus, and would therefore protect you for a longer span of time.
Now that we know that vaccines can be made to target these internal structures, the next step is to decide which ones become part of the vaccine. There are different advantages and disadvantages to the various choices, but the options are narrowing with more and more research. A universal vaccine may be available within the next couple of years.