While myths and half-truths about vaccinations continue to swirl, Dr. Andersen explains how COVID-19 vaccines work.
COVID-19 vaccines are rolling out across the country and becoming increasingly accessible for the general population, bringing hope for a return to normalcy and the end of the pandemic. But simply having the vaccine available isn't enough. Recent public polling found that 30% of the U.S. population plans not to get the vaccine, putting the path to herd immunity through vaccination in peril.
BYU professor Josh Andersen holds a Ph.D. in molecular virology and heads the university's Fritz B. Burns Cancer Research Laboratory. His research has taken him into the world of viruses, immunity, and molecular biology. While myths and half-truths about vaccinations continue to swirl, in this interview Dr. Andersen explains how COVID-19 vaccines work and debunks common misconceptions.
Q: I've heard the Moderna and Pfizer vaccines are 95% effective. What does that mean?
A: In total, over 70,000 people were enrolled in the Moderna and Pfizer phase-III clinical trials. Half of those enrolled received the placebo and the other half received the vaccine. In comparing the two groups, they found the vaccine was 95% effective at preventing COVID-19. That is a remarkable number. Very few vaccines in the history of medicine are even in that ballpark. Even more remarkable is that the number included any positive COVID-19 diagnoses, regardless of whether the symptoms were severe or mild. If you limit the analysis to only include severe cases of COVID-19, the vaccines are essentially 100% effective.
Q: If I've had COVID-19, can't I just skip the vaccine since I already have immunity?
A: Current data suggest that although recovered COVID-19 patients do have some immunity, it may not be as strong and long-lasting as we’d hope.
In a recent study published in Cell, researchers found that SARS-CoV-2 disrupts a critical part of our lymphoid tissues (lymph nodes, spleen, tonsils) called the germinal center, where our body normally refines and develops a strong antibody response. These observations are startling. It's as if a foreign invader (virus) has wiped out our military's central command (germinal center) and crippled our best weapons (antibodies) in the process.
This likely helps explain why at least some recovered COVID-19 patients are vulnerable to reinfection and underscores the need for getting the vaccine whether you've had COVID-19 or not. Recent data suggest that the RNA vaccines significantly boost protection against the delta variant in people who have previously recovered from a natural SARS-CoV-2 infection. These data reinforce the CDC's advice to get vaccinated even if you have previously had COVID-19.
Q: Will vaccines protect against new variants of the virus?
A: As long as individuals carry and transmit SARS-CoV-2, the virus will mutate and change over time, producing new variants that could differ significantly from the original. We've seen this recently as SARS-CoV-2 variants were identified in South Africa and other areas of the world. The worry is that these new variant viruses have changed enough that immune systems won't recognize them, thereby making vaccines obsolete. Thankfully, new reports indicate the vaccines provide at least partial immunity against recently emerged variants.
However, if given time, viruses almost always find a way around defenses. For this reason, we must gain fast and widespread immunity. The vaccine is our best weapon.
Q: How do the currently available COVID-19 vaccines work?
A: The Pfizer and Moderna vaccines are RNA vaccines. To understand how an RNA vaccine works, let's discuss how DNA, RNA, and protein are related. DNA contains your genes. These genes are first transcribed into RNA (like transcribing text from one form to another), which provides the instructions to our cells for making proteins. In turn, proteins make up muscles, cell structures, hair, eyes and skin, and they help perform the chemical reactions in bodies. You can think of RNA as a short-lived messenger that simply relays information from DNA genes to the machinery in cells that make protein.
Viruses, like cells, also have genes that encode for proteins—viral proteins—which viruses use to build their structures. Herein lies one of the most beautiful features of biology: our brilliant immune system recognizes these viral proteins as foreign and builds antibodies against them. It's essentially a state-of-the-art radar surveillance system that deploys precision weapons (antibodies) to destroy the viral invader.
One component of SARS-CoV-2 recognized by our immune system is the spike protein, which sits on the surface of the virus. For this reason, all of the current SARS-CoV-2 vaccines (including the ones awaiting FDA approval) share the common goal of immunizing us against the spike protein.
The Pfizer and Moderna vaccines contain an RNA that produces the spike protein from SARS-CoV-2. It doesn't produce the entire virus, but rather only the spike protein—one tiny part of the virus. This spike-encoding RNA is encapsulated in a lipid (fat) particle, which is simply a vehicle to get the RNA into our cells. Once inside our cells, our protein-making machinery finds the RNA and produces spike protein. In turn, spike protein is recognized by our immune system and antibody production ensues.
The recently approved Johnson & Johnson vaccine differs from the RNA vaccines in its delivery system. It uses an adenoviral vector, derived from a common adenovirus that's been modified so that it can't replicate itself in the body, but instead is simply a delivery vehicle to make spike protein. With only one shot (rather than two with the RNA vaccines) and a 28-day wait, it is 66% effective at preventing COVID-19, and 100% effective at preventing hospitalization.
Q: Can the RNA vaccines change my DNA?
A: No, the vaccine cannot change your DNA. RNA is chemically different than DNA, and our cells cannot incorporate RNA into DNA. The only lasting effect of the vaccine should be immunity to SARS-CoV-2.
Q: Can I get COVID-19 from the vaccine?
A: No. COVID-19 is caused by an active SARS-CoV-2 infection. The vaccine only includes one small part of the virus—the spike protein.
Many who have received these vaccines report mild flu-like symptoms. These symptoms are a result of our immune system recognizing the spike protein as foreign and essentially pulling the fire alarm; calling other immune cells to action to create long-term antibody-mediated immunity. We should welcome these symptoms as a sign the vaccine is working.
Q: I've heard these vaccines are based on new technology. Are they safe?
A: Yes. The current COVID-19 vaccines have been FDA authorized as safe through clinical trials and rigorous evaluation. The technology behind the COVID-19 RNA vaccines is not new. These vaccines are a triumph of decades of research focused, in part, on how to stabilize RNA and deliver it to cells.
Some have expressed surprise about how quickly these vaccines received FDA approval. It was a remarkable feat that leveraged years of previous research on vaccines and coronaviruses and the mobilization of immense resources and cooperation of scientists worldwide. Researchers around the globe dropped other projects to focus solely on COVID-19, and research was shared freely. It was the kind of incredible and inspired effort that happens in a global crisis.
Q: I've heard people have died from the vaccine. Is this true?
A: No. In the Pfizer and Moderna clinical trials, tens of thousands received the vaccine under the intense scrutiny of FDA regulators and clinicians. Also, over 60 million vaccines (and counting) have been administered in the U.S. alone. Not a single death has been attributed to the vaccine.
As with all vaccines, there is a very small risk of an allergic reaction to the vaccine ingredients. These generally happen within minutes of the vaccine in people with a history of allergies and have been treated with allergy medications.
Q: I've heard these vaccines contain suspicious ingredients. Is that true?
A: No. Rumors that the vaccine contains fetal tissue or other unusual ingredients are false. The FDA has published the ingredients of these vaccines. They contain the aforementioned messenger RNA (mRNA) and lipids in a salt and sugar buffer that helps stabilize the lipid RNA particle. There is nothing unexpected or alarming in the ingredient list.
To learn more about the safety and effectiveness of the COVID-19 vaccines, visit the CDC website.
To learn more about Dr. Andersen and the BYU Fritz B. Burns Cancer Research Laboratory, click here.
