The Director’s Cut: With so much information available about vaccines, CRA Medical Director Dr. Stephen Sharp wants to help you cut through the clutter. Below, Dr. Sharp uses his professional expertise to break down exactly what a vaccine is, and help you understand how scientists research vaccines. At CRA, we want to help you make the best decisions for your own health.
How We Research Vaccines
When a person gets infected with a microbe (whether virus, bacteria, fungal, or parasite) a chain reaction takes place in the body’s immune system. One of those events is identifying the invader as foreign and passing its unique characteristics, called “epitopes,” to cells that memorize them and to cells that make antibodies against them. The purpose of a vaccine is to provoke that same response.
The original approach was called “inoculation,” whereby infected material from a sick person was injected into a healthy person. Later approaches used weakened versions of the microbe as the active ingredient in vaccines. The problem with these methods is that it could produce the infection and all its consequences in the vaccinated patients.
Once we had the technology to identify the epitopes of these microbes, scientists used a new approach to develop vaccinees by just using the epitope. These are usually small pieces of surface proteins, like the Covid-19 spike protein or the influenza surface proteins. The body reacts as if it has been infected, and your immune system makes antibodies and memory cells to guard against these epitopes without the risking infection. The immune system also responds by releasing chemicals called “cytokines,” that produce fever, chills, muscle aches, headache, and other familiar symptoms we recognize as “vaccine reactions.” Unfortunately, this reaction fools some people into thinking they “got the flu from the flu shot.” The difference is that vaccine reactions are milder and briefer than actual illness, and don’t carry the same long-term consequences as the actual disease, like deafness from measles or “long Covid.”
New approaches to vaccine development and production were accelerated following the attacks on 9-11-2001, when fears of bioterrorist attacks arose. Consequently, we can now develop and mass-produce vaccines faster than ever before. The most famous of these new approaches is the mRNA vaccine, which takes the code for making the epitope, and teaches our ow cells how to produce that target for the immune system. Within a couple of days, the mRNA is gone but the body will have enough epitope produced to develop a robust antibody response. When it comes to the science behind vaccines, we hope you have learned something today.