Reviewing Vaccines as Pfizer Says COVID-19 Vaccine Safe for 12-Year-Olds

COVID-19 vaccine being studied for use with teenagers, ages 12-17

By Jonny Lupsha, Current Events Writer

Pfizer’s Covid vaccination may be safe for children as young as 12, but what exactly is in a vaccine?

a teenager receives the coronavirus vaccine
Unlike vaccines of the past, COVID-19 mRNA vaccines do not have dead virus components; instead they tell the body’s cells to make a harmless piece of the protein spike that is on the surface of the virus. (Image: Shutterstock/Halfpoint)

The newly developed mRNA vaccines do not contain a live virus or a weakened or inactivated germ of the novel coronavirus; instead, they teach our bodies how to make a protein that triggers an immune response in our bodies, which protects us against COVID-19. Before mRNA vaccines, however, the contents of vaccinations have evolved considerably in the last century. Inoculations used to simply utilize living viruses or bacteria and were little more than controlled infections. Next came attenuated vaccines, which were essentially viruses mutated in other species to make them less virulent.

Then came inactivated vaccines, which contained dead or nearly dead viruses to train your body to fight the real thing. Still other vaccines contained just part of the virus or protected only against its toxins.

With Pfizer’s recent announcement that its COVID-19 vaccine is safe for children as young as 12, many are asking: What is in the mRNA vaccines and how do typical vaccines of the past work? In his video series Medical Myths, Lies, and Half-Truths, Dr. Steven Novella, Assistant Professor of Neurology at the Yale School of Medicine, explained the contents of a typical vaccine and its average effectiveness.

Why Include So Much Stuff?

“There are more in vaccines than just the viruses or the bacteria or the components of that; those are what we call the antigens,” Dr. Novella said. “The antigens are the things that active your immune system—it’s what your immune system is binding to—but we have to put other things in vaccines in order to make them work as well.”

According to Dr. Novella, one type of thing mixed into a vaccine is called an adjuvant, which is defined as anything that’s designed to enhance the immune system’s response to the antigen. Adjuvants either stimulate the immune system to make it more active or prolong the exposure of the antigen to the immune system. Adjuvants are frequently made up of oils or aluminum salts.

“Another constituent of vaccines are preservatives,” he said. “We have to both preserve the components of the vaccine itself and prevent contamination. [For example] antibiotics are often used to prevent bacteria from growing in the vaccines themselves.”

Stabilizers like monosodium glutamate (in very low doses) prevent vaccine proteins from degrading, while vaccines may also contain constituents like egg protein, in which the vaccine may have been cultured.

Vaccine Effectiveness

Even today, there is still doubt as to whether vaccines work.

“The evidence is extremely clear,” Dr. Novella said. “Vaccines are about 95% effective, which means that 95% of people who are vaccinated with a vaccination schedule—which may involve boosters that have been shown to be effective—will develop a functional immunity to the substance against which they are being vaccinated. So 95% effectiveness, that’s pretty good.”

Vaccines are sometimes less effective in the elderly or the immunocompromised, who of course need the protection against viruses the most. However, it’s unreasonable to expect the elderly or immunocompromised to simply stay home the rest of their lives to avoid risk of infection. This is where the subject of herd immunity comes in.

“Vaccines are safe and effective for the individuals who receive them,” Dr. Novella said. “But in addition, being vaccinated protects those people around us. There are estimates that when about 90% or more of any population—people who are likely to be exposed to each other—are vaccinated against an infection, that you achieve what’s called ‘herd immunity,’ that that infection cannot easily spread from person to person.

“Anyone who is harboring the virus or bacteria is very unlikely to encounter somebody else who isn’t resistant, who isn’t immune, and therefore they’ll be able to fight it off before they spread it around.”

Vaccinations and herd immunity effectively ended smallpox and nearly ended polio, were it not for conspiracy theories and misinformation regarding the polio vaccine.

Edited by Angela Shoemaker, The Great Courses Daily

About Jonny Lupsha, News Writer 824 Articles
Jonny is a freelance writer and novelist who lives in Sterling, Virginia. He has written for The Great Courses since 2017 and enjoys studying the courses as much as writing about them. Contact Jonny at lupshaj@teachco.com