Your loved ones are right to have questions about the Covid-19 vaccine — the American public hasn’t watched vaccine development this closely since Dr. Jonas Salk discovered how to immunize kids from polio in the ’50s.
But vaccine hesitancy could put a dangerous damper on the country’s response. Pockets of some populations most at risk of severe sickness from Covid-19, including young nurses and Black Americans, are still dubious of the vaccine — because of the speed at which it was developed, its contents and potential side effects.
To answer questions your family and friends may have about the Covid-19 vaccine, we consulted with two experts:
- Dr. William Schaffner, a professor in the Division of Infectious Diseases at the Vanderbilt University School of Medicine
- Dr. Ruth Karron, a leading vaccine expert and professor of international health at the Johns Hopkins Bloomberg School of Public Health.
Medical experts, successful clinical trials and the Centers for Disease Control and Prevention have repeatedly assured us of the safety and effectiveness of the two Covid-19 vaccines available now, from Moderna and Pfizer.
But health experts take your concerns seriously, too, said Schaffner.
“We have to regard everybody’s hesitation and skepticism seriously,” he said. “This is a new virus in the human population, new vaccines using new technologies, so you understand that people are somewhat hesitant.”
If they say:
“I don’t know what’s in the vaccine.”
You can say: That’s fair. Vaccine ingredient lists include a lot of lengthy names only a chemist would recognize.
Here are the some of the main ingredients in the Moderna and Pfizer vaccines, the two vaccines currently authorized for use, and how they work:
mRNA: Short for messenger ribonucleic acid, mRNA is a “genetic software” that tells cells how to make the coronavirus spike protein, the structure the virus uses to invade cells. The mRNA gets your immune system’s attention, so it’s prepared to attack the spike protein if infection occurs. The mRNA disintegrates as soon as it relays its message, Schaffner said, and you excrete its remnants.
Fatty lipids: The mRNA is very fragile, so it’s coated in a fatty lipid to protect it. The lipids, a buttery substance, can melt at room temperature — which is why both vaccines must be kept at extremely cold temperatures. Fatty lipids used in Covid-19 vaccines include polyethylene glycol-2000 and cholesterol, among others.
Salts and sugars: Salts such as potassium chloride and sodium chloride are in the vaccine to balance the acidity in your body, according to the MIT Technology Review. Sugar, listed as sucrose, is there so the vaccine nanoparticles keep their shape.
Other vaccines still in trials in the US, such as AstraZeneca’s, rely on different technologies than mRNA and, therefore, have different ingredients.
If they say:
“The vaccine was created too quickly to be trustworthy.”
You can say: It’s true that the Covid-19 vaccines currently authorized for emergency use by the US Food and Drug Administration were developed and tested more quickly than other vaccines we’re familiar with. But extensive clinical trials have proven their effectiveness.
Part of the reason why the vaccines were developed rapidly is because the circumstances called for speed: We’re in a pandemic that’s killed more than 2 million people worldwide and sickened over 103 million people. The need for a vaccine is urgent.
So rather than wait for the results of trials to manufacture a vaccine, the companies creating these vaccines produced them simultaneously so they’d be ready to deploy when the trials were completed, Schaffner said. Typically, the companies that create vaccines would wait for a trial to end before giving the OK to manufacture the vaccines.
“Of course, our ‘bet,’ if you will, came up a winner,” Schaffner said. Both Pfizer and Moderna’s vaccines are 94% to 95% effective at preventing severe sickness from Covid-19.
The technology the vaccines use, mRNA, was developed long before the virus that causes Covid-19 began to circulate in humans, so the tech can be trusted, Schaffner and Karron said.
The Covid-19 vaccine trials included tens of thousands of participants, Karron said, whose reactions to the vaccine were closely monitored for months before the vaccines were approved by the FDA.
Vaccine developers also had the resources to speed up the process — there were no questions of demand or funding, Karron said.
If they say:
“The vaccine could give me Covid-19.”
You can say: The vaccine cannot give you Covid-19, Schaffner said, because it doesn’t contain the virus. It contains mRNA, or messenger ribonucleic acid, which tells your cells how to create the protein spike the virus uses to infect other cells.
The live virus never enters your body in the vaccination process, Karron said — your cells learn how to make a part of the virus, but coronavirus can’t replicate that way.
You may experience some “intense but brief” symptoms like fatigue, nausea and a low fever after you’re vaccinated, she said. Those are often synonymous with Covid-19, but these vaccine-induced side effects should subside within 24 to 48 hours, she said.
It’s also possible you could suffer no side effects, Karron said, or they could be as mild as a headache and a sore arm. In any case, you won’t get Covid-19 from getting vaccinated.
READ MORE: Your coronavirus questions, answered
If they say:
“The vaccine could alter my DNA.”
You can say: The Covid-19 vaccines do not alter or interact with your DNA.
The mRNA never enters a cell’s nucleus, which houses DNA, Karron said. It does its work in the cytoplasm, the fluid within a cell.
The mRNA doesn’t stick around in the body, either. It dissolves once it’s sent a message to cells and exits your body, Schaffner said.
If they say:
“The vaccine could give my child autism or a birth defect.”
You can say: This is not true. Several studies have repeatedly shown that vaccines do not cause autism or development issues in young children. That belief is based on a bunk study from the 1990s that has since been retracted.
As stated above, the Covid-19 vaccine does not interfere with DNA.
If they’re worried about the risk of getting vaccinated while pregnant, this may assuage their fears: The American College of Obstetricians and Gynecologists recommended the Covid-19 vaccine for people who are pregnant or breastfeeding.
It’s also wise to get vaccinated, Schaffner said, because pregnant women are thought to be at a higher risk of severe illness from Covid-19. Compared to symptomatic people who are not pregnant, pregnant people are at a higher risk of ICU admission, the need for a ventilator and death, according to the American College of Obstetricians and Gynecologists.
If they say:
“The vaccine’s side effects could be severe.”
You can say: It’s unlikely that you’ll have a severe reaction to the Covid-19 vaccine. It’s much more likely that you’ll have a “local reaction,” such as redness and soreness in your arm or a low fever, Schaffner said.
Side effects of the vaccine tend to be more severe after the second dose of the Moderna or Pfizer vaccines, Karron said, so it’s smart to plan around that. You may want to take a day off work after you get the vaccine in case you’re too fatigued. The symptoms tend to be more severe in young people than older folks who get vaccinated, she said.
“It’s a small price to pay to prevent Covid,” Karron said.
If they say:
“I could have an allergic reaction to the vaccine.”
You can say: This is possible, but very rare: About 11 cases per one million cases of Covid-19 vaccinations resulted in an allergic reaction, Karron said.
People with severe allergies or those who carry an EpiPen should consult with their doctor before they get vaccinated, she said, but even those with allergies have gotten the vaccine without a reaction.