Thinking about getting a vaccine? For a better understanding of how COVID-19 vaccines work, I think it is helpful to understand how the virus causing COVID-19 operates.
I like to think of SARS COV-2 as a sneaky, larcenous, scary jester type of clown with a crazy spiked hat that preys upon the delicate, peace-loving cells that line our mucous membranes throughout the lungs, mouth, nose and gut. I imagine those cells to be like a row of houses that serve as a border and barrier for the town that is our bodies. The jester uses its spiky hat like a key to a lock — in this case the lock is called an Angiotensin Converting Enzyme-2 receptor — to gain entry to human cells. Once in the house, the COVID jester takes out a 3D printer, scrounges around in the house for raw materials to use in the printer, adds its own genetic code and proceeds to print exponential replicas of itself.
All of those replicas trash the house then start pouring out the windows and doors, creeping down the streets to find more houses. The owners of the house may manage to capture a couple of jesters and display the intruders in a call for help from first responders. But each town has a different fire and police program. In some towns a firetruck shows up for a small kitchen fire started by a jester and in response they flood the house with water, destroying the house completely. In some towns the police may show up with armored vehicles sporting cannons, which also does not turn out well for the house. In some towns the first responders don't show up at all.
Similarly for some people, the immune system's first responders may flood cells with inflammatory chemicals and immune cells, or there may be little to no immune response at all in response to the jester's violation.
This is why there is such variability in severity of illness in humans. Incidentally, older people have a higher proportion of Angiotensin Converting Enzyme-2 receptors in their lungs compared to younger people. This may be one factor leading to worse outcomes for older people.
There are dozens of vaccines in the works, some that present recipients' immune systems with neutered, weakened jesters. Some vaccines introduce our immune systems to just the spiky jester hat, while others put the spiky jester hat on a common, weak virus that enters our cells and permits a protective immune response to the spiky hat without much other illness.
While COVID-19 is new, many of these vaccine platforms have been used to develop vaccines for other diseases. Some never made it through clinical trials because often when an infectious crisis ceases, funding for vaccine development and clinical trials also ceases. This was the case for vaccines developed for MERS, SARS COV-1 and the Ebola virus. Everything was ready to go for all of those vaccines to move to clinical trials, but when the crisis was over, funding dried up.
Of all the vaccine platforms to prevent COVID-19, the messenger RNA vaccines produced by Pfizer and Moderna represent a brilliant advancement in vaccine technology. The elegance of the mRNA platform is that they are like a message in a bottle with the message being the genetic code used by our cells to produce just the jester's spiky hat, prodding us to develop protective antibodies and educating our immune system about the invader. The mRNA vaccines deliver these little strands of genetic information within a dissolvable coating of lipid nanoparticles, technology that has been successfully used for immunotherapies and cancer treatments for over a decade.
Once delivered by injection, these nanoparticle bottles are absorbed by cells that reside in our skin and initiate the immune response that carries on throughout our bodies. MRNA messages are only translated outside of the cell's nucleus control center, so the cell's DNA is not altered in any way and the messages rapidly dissolve.
Let's be clear: The foundational work for mRNA-based vaccines has been ongoing for decades. These new vaccines were not rushed. The preparatory work had already been done, and technology allowed them to be developed and produced efficiently. Clinical trials were conducted in parallel, rather than serially, which allowed more efficient delivery of data to the FDA, which has dedicated unprecedented resources to the evaluation of a vaccine.
I received the Pfizer mRNA vaccine on Dec. 23 and got my booster on Jan 14. I feel great and very fortunate. I hope the difficulties with distribution get worked out so my loved ones and everybody else have a chance to get protected. I know I won't be doffing the mask and licking doorknobs anytime soon, but it will be nice to know it will be a lot less likely for me to give SARS COV-2 to anybody else.
Matt Thompson is a pediatrician at Spokane's Kids Clinic.
