The safety and efficacy of Modern and Pfizer’s vaccines — both of which have proven more than 90 percent effective in phase III clinical trials — have been hailed as a “spectacular success” by the science world. But among the general public, fear about potential side effects, spurred by misinformation and lies on social media, have led many to determine that they will opt out of taking it. That decision could have major repercussions, not only for individuals but for the U.S. as a whole. With explosive spread nationwide, experts have concluded that herd immunity through vaccination is the only way that the pandemic will end.
While it’s true that most vaccines take years — some even decades — experts on RNA and vaccines who spoke with Yahoo Life say that safety data suggests the mRNA vaccines are unlikely to cause serious side effects — and may even be safer than their more conventional counterparts as doctors work to create immunity to a virus that has killed more than 280,000. As the Food and Drug Administration meets this week to discuss Pfizer-BioNTech SE’s COVID-19 vaccine, experts break down some of the biggest myths about RNA vaccines.
Myth: This is the first time the mRNA vaccines have been tested on humans
Both Pfizer and Moderna’s vaccines rely on what’s known as messenger RNA (mRNA), a technology that carries the genetic code of SARS-CoV-2 into the cells where it’s recognized as foreign, triggering an immune response. Although mRNA has yet to be utilized in an approved vaccine, experts say this doesn’t mean that the concept has never before been tested on humans.
“It’s a relatively new technology, but we’re probably looking at maybe a decade or two that they’ve been tinkering with it and toying with the idea and using it,” says Richard Kennedy, an immunologist and co-director of the Mayo Clinic’s Vaccine Research Group. Florian Krammer, a renowned professor of vaccinology at the Icahn School of Medicine at Mount Sinai echoes his thoughts, saying the technology has been studied with both the Ebola virus and influenza. “It has been tested in humans since 2013,” says Krammer.
Myth: mRNA vaccines are more dangerous than other vaccines
Kennedy further explains that, because of the nature of RNA, these vaccine candidates may turn out to be safer than other vaccines containing live attenuated virus, meaning a weakened form of the virus. “One of the benefits of mRNA vaccines is everything can be done by a machine so you don’t have to worry about bacterial contamination or other contaminants. There’s no live virus in the vaccine so everything that goes into it can be very carefully controlled and monitored,” says Kennedy. “mRNA vaccines are no more dangerous than other vaccines and it’s possible they're a little safer.”
Myth: There is no long-term safety data about mRNA vaccines
One of the most prevalent myths about mRNA vaccines is that they haven’t been tested long enough to yield long-term safety data. As Krammer tweeted, it’s true that there is little long-term safety data, but not true that there is none. He says in the seven years since mRNA vaccines were first tested in humans, no serious side effects have been reported. To be sure, this isn’t necessarily surprising, given that things like Guillain Barré Syndrome occur in just one out of a million people who receive the flu vaccine.
But Krammer adds a crucial point: Adverse outcomes like this almost always occur rapidly. “These things happen relatively quickly after vaccination, they don't happen 15 years down the road,” says Krammer. “They happen two months after the vaccination when the immune system is the most active. So these two months that the FDA mandated, they had a reason for that, because in that window, you see a lot.”
Kennedy agrees. “The vast majority of adverse events and side effects after vaccination occur within a week or two — and probably 95 percent of them happen within six weeks of getting the vaccine,” he says. “So the vast majority of what we're concerned about is going to be captured within six weeks and we already have that data, or at least the companies have submitted that data to the FDA.”
Myth: mRNA vaccines could potentially alter your DNA
A troubling myth that has been widely circulated on Facebook is that an mRNA vaccine can alter an individual’s genetic code. Both Krammer and Kennedy say this is not true for the simple reason that it’s not possible. “Our genome is DNA and we have all of the enzymes and machinery to make copies of that,” says Kennedy. “We don't have any of the machinery in our cells to take the RNA and change it back into DNA. Otherwise, you would be doing that every time we're infected with any virus.”
“The pathway from DNA to RNA is a one-way street,” Krammer adds. “The other way doesn't work. So it does not change your genome at all — and it could be safer than many other vaccines.” Mark Lynas, a visiting fellow at Cornell University’s Alliance for Science, echoed their thoughts to Reuters. “That’s just a myth, one often spread intentionally by anti-vaccination activists to deliberately generate confusion and mistrust,” Lynas said. “Genetic modification would involve the deliberate insertion of foreign DNA into the nucleus of a human cell, and vaccines simply don’t do that.”
Myth: mRNA vaccines can make you sick, and cause side effects in 75 percent of people
In early November, a White House correspondent for Newsmax tweeted that “75 percent of vaccine trial participants experienced side effects” from the mRNA vaccine. This is false. According to early data from Moderna, released by an independent review board, the two most common side effects were fatigue and muscle aches, both of which occurred in under 10 percent of participants. Pfizer-BioNTech SE’s vaccine produced even fewer side effects, with 3.8 percent of individuals reporting fatigue and 2 percent fever.
Krammer says these reactions, which typically resolve within 48 hours, are a normal response to vaccines — one that shows it is working as intended. “You may get elevated temperature, headache or muscle aches. What happens there is that your innate immune system recognizes that there's something in your body that doesn't belong there and sounds the alarm,” he says. “People need to know. If you feel sick, it’s not because a virus is infecting you it’s because the vaccine is triggering [an immune response].”
Myth: Getting COVID-19 is safer than taking an mRNA vaccine
Although this week the Pew Research Center reported that 60 percent of Americans would take a COVID-19 vaccine, two in 10 Americans are reportedly still opposed to taking it. For those who think that getting infected with COVID-19 is a safer option, Krammer says think again. “We have a vaccine that has been tested in 40,000 people and hasn't caused any severe side effects; we have a virus that is very prevalent and can cause very severe disease and can kill you,” says Krammer. “And even if you don't have severe disease, it might cause long-lasting symptoms. If you look at both cases, I would take the route of lower risk.”
He says that the high likelihood of getting COVID-19 versus the possibly one in a million chance of having a severe reaction to a vaccine makes it an easy decision. “You know, people want to have control over their lives and their body, right? And so, if I decide to get the vaccine, then I make the decision for myself and then I am protected. If I don’t get the vaccine, I might get infected at any time and I can't control the course that the disease runs,” Krammer tells Yahoo Life. “It might be mild, but it might also send me to an ICU. And so, I think, look at the risk realistically. Do you want to control your situation, your body, your life, or not? I think the vaccine is a good way to help with that.”
For the latest coronavirus news and updates, follow along at https://news.yahoo.com/coronavirus. According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.
Read more from Yahoo Life
Want lifestyle and wellness news delivered to your inbox? Sign up here for Yahoo Life’s newsletter.