Pfizer and Moderna grabbed headlines, and ushered in hope, in announcing this month that each company has vaccines that preliminary data suggest to be 90-94% effective in preventing Covid-19 infections. This news is a much-needed salve to a world that has surpassed 1.37M deaths from Covid-19 since January 2020.
These genetic vaccines are different from other vaccines, like those for the flu, measles, and polio, that we’ve benefited from for decades. Traditional vaccines, like that for measles, work by injecting a small amount of a weakened form of the virus into the body. Our white blood cells sense the virus and mount a defense against it by creating specific antibodies to fight it. Our immune system has cells, called T-lymphocytes, that remember that virus, so if our body encounters measles in the future, we can make the antibodies needed to fight it immediately. These traditional vaccines take years, or decades, to create, test, and be approved, and are expensive to produce.
The Pfizer and Moderna vaccines take advantage of a different, genetic approach, that uses using a molecule called messenger RNA (mRNA), something you may not have thought about since high school biology class. In short, DNA is the genetic instruction manual for our bodies. mRNA makes a copy of that manual and carries it out of the cell’s nucleus to structures called ribosomes, where that manual is used to make proteins. Those proteins play many critical roles in our body.
These genetic vaccines work by injecting just the mRNA instruction manual, and not the actual virus, into the human body. In fact, these vaccines use just the mRNA instructions used to create the spike protein from the coronavirus that Covid-19 uses to invade human cells.
This illustration, created at the Centers for Disease Control and Prevention (CDC), reveals … [+] ultrastructural morphology exhibited by coronaviruses, 2020.…