About the COVID Vaccine

by Charles Kenny, M.D.

The development of vaccines began over 1000 years ago with observations that dried material from skin sores of convalescing smallpox victims conferred protection against death from the disease when blown into the nostrils of healthy persons (variolation).

Salk vaccine

Salk polio vaccine exemplifies the difficulties encountered with mass-production. First polio virus had to be cultured in susceptible animals, usually monkeys. The virus then isolated was treated with various chemicals, such as dilute formalin solution, to inactivate it. A sample of the weakened virus was injected into healthy monkeys, and, if these animals developed immunity, the vaccine was tested on humans. Many monkeys had to be sacrificed, and many early trials were unsuccessful. The process took several years.

Today we have mRNA-based vaccines

Coronavirus is an extremely abbreviated life-form. A small strand of genetic material, RNA (ribonucleic acid), is surrounded by a shell of glycoprotein with attached sugars sticking out that is specially configured ("spike protein") to act like Velcro when the virus comes in contact with human cells in the nose and upper airway. Adjacent to the Velcro part is another protein covered with sugar that acts like scissors and snip a hole in a cell's membrane. The viral RNA enters through the hole and takes over.

Normally, a cell makes protein by inducing its own RNA molecules to self-assemble along a gene's DNA. The RNA then lifts off, is edited, and is spliced into one long chain called messenger mRNA. This mRNA travels to another area of the cell to make the protein.

The invading viral genetic RNA acts like the cell's own DNA and takes over, making only viral glycoprotein and RNA for thousands of new viruses, until the cell bursts.

Subverting the virus' routine

Medical science has subverted the virus's routine. Using highly complex chemical procedures, we now know the entire viral RNA code. We can also make specially tailored mRNA that codes only for the spike protein. This custom mRNA does not code for any other part of the virus.

The miracle that allows this scheme to work is that when mRNA is injected into the human skin, the cells absorb it and use it to make protein, just as if it had been assembled during the usual protein making process. But this protein is just the spike protein; complete viral particles are not made. Nevertheless, the body's immune system reacts to the spike protein as if it were part of an entire virus. After several weeks and an additional booster shot, we become immune.

Editor's note: Charles Kenny, MD is chair of the Stockbridge Board of Health.