From the time Edward Jenner conceived of the idea of a vaccine, the science of vaccines has been based on a simple concept, that of using an organism similar to the pathogen to protect the patient from that pathogen. Jenner’s use of cowpox to immunize against smallpox is the classic example. But progressions in medical science and viral understanding have give us new tools for new vaccines, especially flu vaccines.
From that pioneering work of those first vaccines, it was quickly discovered that if a similar organism is unavailable, a weaker form of the original pathogen can get a response. This “attenuated” organism now forms the basis for most flu vaccines produced today. But there is a problem with this approach, one that we face each flu season.
The variability of the flu virus is legendary, so much so that there is no longer a single flu virus, but a host of similar strains that can produce the same disease. In contrast, take the disease of syphilis. It is caused by the same pathogen, a microorganism called T. palidium that has always caused the disease. But with a flu virus, attenuating virus A1 won’t protect you against virus A2, or A3, not to mention flu viruses B through Z. So the attenuation strategy for vaccine production becomes a large hammer that may or may not do what you are planning.
But now we enter the fascinating world of protein chemistry. The thing that changes about a virus is the protein coat of the flu virus. Because this is not a whole scale mutation, the change can occur rapidly. And to add to the insidious nature of the virus, it may not be even the whole protein.
The protein structure has pieces, and that discovery may lead directly to the a new vaccine. It has been discovered that a viral protein called hemagluttin, changes the protein “head,” leading to new viral coats which means a new viral type. But the stalk that the “head” is stuck on does not change.
Vaccines are now in development that target that stalk. Once it reaches a successfully and practical format, we may be able to produce a single vaccine that will work for multiple viruses no matter how much they change.