En español | More than 245 million Americans have rolled up their sleeves for the coronavirus vaccines, but still a significant share of the eligible population (about 40 percent) is not fully vaccinated.
A big reason: False information spread online and in person has persuaded many people to skip the shot. In fact, a 2021 Kaiser Family Foundation report found about 80 percent of adults who say they will “definitely not” get the vaccine believe or are unsure about at least one prevailing COVID-19 vaccine myth. And a majority of adults (54 percent) either believe some rampant misinformation about the COVID-19 vaccines or are unable to debunk it.
Facts are especially important as new COVID-19 cases, hospitalizations and deaths climb throughout the U.S., driven largely by the highly contagious delta and omicron variants. Here are some common coronavirus vaccine myths and the truth behind each one.
Myth 1: The vaccines were developed too quickly to be trusted.
It’s true that the COVID-19 vaccines arrived in record time, but the steps that were hurried “were essentially the paperwork,” Andrew Bradley, M.D., a vaccine expert and professor at the Mayo Clinic, explained in a recent media briefing.
All three available vaccines in the U.S. — from Pfizer-BioNTech, Moderna and Johnson & Johnson — were tested in tens of thousands of people in clinical trials and rigorously evaluated for their safety and effectiveness.
Scientists had a bit of a leg up from the beginning, which helped to accelerate the process. The virus that causes COVID-19 is related to other coronaviruses that have been under the microscope for years, including those that cause severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). “The knowledge gained through past research on coronavirus vaccines helped to accelerate the initial development of the current COVID-19 vaccines,” the Centers for Disease Control and Prevention (CDC) said.
Investing in early manufacturing and distribution also got shots in arms faster than usual.
And while two of the vaccines (Pfizer’s and Moderna’s) are a new type of vaccine, called mRNA (messenger ribonucleic acid), researchers have been studying the technology for decades across a range of diseases, including flu, Zika and rabies — even cancer. This type of vaccine delivers a set of instructions to the cells and teaches them to make a protein that then produces an immune response to the virus.
Pfizer’s COVID-19 vaccine has received full approval from the U.S. Food and Drug Administration (FDA); Moderna’s and Johnson & Johnson’s are being administered under the FDA’s emergency use authorization (EUA).
Myth 2: The vaccines will alter your DNA.
None of the vaccines interact with or alter a person’s genetic material, known as DNA (deoxyribonucleic acid), the CDC confirmed. The vaccines help the cells build protection against a coronavirus infection, but the vaccine material never enters the nucleus of the cell where the DNA lives.
When it comes to the mRNA vaccines, after the cell is done using the instructions delivered, it breaks down and gets rid of the mRNA. And the genetic material delivered by the viral vector (used in the Johnson & Johnson vaccine) does not integrate into a person’s DNA, the CDC said.
Myth 3: If you’ve had COVID-19 already, you don’t need to get vaccinated.
Even if you’ve had COVID-19, experts recommend getting vaccinated — and boosted, if you’re eligible.
One reason: It’s unclear how long you are protected from the disease after a previous infection. Another reason: New research suggests that the COVID-19 vaccines offer better protection than natural immunity and can help prevent reinfections.
A study published Aug. 13 by the CDC found that unvaccinated individuals who already had COVID-19 were more than twice as likely as fully vaccinated people to get COVID-19 again. And research published in The Lancet suggests that older adults are more likely to be reinfected with COVID-19 than younger populations — a difference that can likely be explained by natural changes that weaken the immune system as you age, the authors noted.
If you had COVID-19 and were treated with monoclonal antibodies or convalescent plasma, the CDC recommends waiting 90 days before getting the vaccine.
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Myth 4: You can ditch your mask after you get vaccinated.
People who have been fully vaccinated can resume many pre-pandemic activities, but going completely mask-free isn’t recommended. The CDC is still encouraging everyone, regardless of vaccination status, to wear a mask in public indoor settings in order to curtail the spread of the virus, especially in the wake of the highly contagious omicron variant.
The reason? Research shows that while fully vaccinated and boosted people are mostly protected from serious illness if infected with the delta or omicron variants, it’s possible for them to spread the virus to others, including someone who is unvaccinated or immunocompromised.
Myth 5: The vaccines use a live version of the coronavirus.
None of the authorized vaccines in the U.S. use the live virus that causes COVID-19, and they cannot give you the disease or cause you to test positive for a coronavirus infection. Instead, the vaccines use scientific techniques to train the human body to recognize and fight the coronavirus.
The Pfizer-BioNTech and Moderna vaccines deliver a set of instructions to your cells to encourage your body to produce antibodies. The Johnson & Johnson vaccine works differently. It uses a harmless adenovirus that can no longer replicate to send a genetic message to your cells.
While the coronavirus vaccines will not make you sick with COVID-19, they can cause side effects in some people. Commonly reported side effects include injection-site pain, fatigue, headache, chills, fever and muscle aches. Most of the reactions are temporary and resolve within a few days, according to the CDC.
Myth 6: You don’t need both doses of the two-dose vaccines.
Both the Moderna and the Pfizer-BioNTech vaccines require two doses that are given a few weeks apart. And experts stress that both shots are needed for optimal protection. And in fact, a third booster dose five months after the primary series is strongly encouraged to prevent getting sick from an infection caused by the omicron variant.
A study published by the CDC in May found that a single dose of the Pfizer or Moderna vaccine was about 80 percent effective against symptomatic COVID-19; two doses were 94 percent effective. Research since then shows that the level of protection drops when confronted with both the delta and omicron strains, which is why a booster is encouraged.
Myth 7: The vaccines contain microchips or can cause you to be magnetic.
These two rumors have been circulating on social media, but neither one is true. “Vaccines are developed to fight against disease and are not administered to track your movement,” the CDC said. What’s more, the vaccines do not contain any metals or materials that can produce an electromagnetic field.
They are also free from manufactured products such as microelectronics, electrodes, carbon nanotubes or nanowire semiconductors, as well as from eggs, gelatin, latex and preservatives.
Myth 8: The vaccines can cause fertility problems.
There is currently no evidence that any vaccine, including COVID-19 vaccines, causes fertility problems in women or men, the CDC says. And, in fact, vaccination is recommended for people who are breastfeeding, pregnant or plan to get pregnant in the future.
The National Institutes of Health recently funded a study that explores potential links between COVID-19 vaccination and menstrual changes after some women reported experiencing irregular or missing periods after getting the shot.
Researchers found that some vaccinated women experienced a slight, but temporary, change in their menstrual cycles. Lead investigator Alison Edelman M.D., of Oregon Health & Science University School of Medicine, explained in a news release that the average change is less than one day in the cycle at which vaccination occurred. There were no changes in the number of menstrual bleeding days for the vaccinated individuals, the NIH noted, and delayed cycles “appear to resolve quickly, possibly as soon as the next cycle after vaccination,” Edelman said.
“Our findings are reassuring. On a population level, the changes we are finding indicate no cause for concern for long-term physical or reproductive health,” explained Edelman, a professor of obstetrics and gynecology.
A number of factors can lead to temporary changes in periods. Immune responses to the COVID-19 vaccine are one explanation. Others include pandemic-related stress, lifestyle changes related to the pandemic, and infection with SARS-CoV-2, the NIH wrote. Other studies exploring the link between COVID-19 vaccination and menstrual changes are ongoing.
“These results provide, for the first time, an opportunity to counsel women about what to expect from COVID-19 vaccination so they can plan accordingly,” said Diana W. Bianchi, M.D., director of NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).
Myth 9: You shouldn’t get the vaccine if you’ve ever had an allergic reaction.
If you have a history of allergic reactions to oral medications, food, pets, insect stings, latex or things in the environment like pollen or dust, you can safely get the COVID-19 vaccine, the CDC said. You can also get the vaccine if you have an egg allergy, because none of the authorized vaccines contain eggs or egg-related components.
The only group the agency says should definitely abstain are people who have had a severe allergic reaction to any ingredient in a COVID-19 vaccine. If you’ve had an allergic reaction to other vaccines or to injectable medications, the CDC recommends talking to your medical provider about whether to get the vaccine.
Only a small number of the people who have received a COVID-19 vaccine so far experienced the severe allergic reaction called anaphylaxis. Anaphylaxis has affected about two to five people per million vaccinated, the CDC says. Although anaphylaxis is life-threatening, it almost always occurs within 30 minutes of vaccination and can be quickly halted with a medicine such as epinephrine.
The agency recommends that people with a history of anaphylaxis stay on-site for observation for 30 minutes after vaccination. Those with no history of anaphylaxis should stay for 15 minutes.
Myth 10: COVID doesn't affect kids as much, so they don't need the vaccine.
It's true that youngsters tend to fare better than older adults when COVID strikes, but the disease still very much affects them.
Hundreds of children have died since the start of the pandemic, and thousands have been hospitalized — even more so since the emergence of omicron. Also, "we've had thousands who have developed something called multisystem inflammatory syndrome, which is one of these conditions where multiple organ systems, including the heart, are affected," U.S. Surgeon General Vivek Murthy, M.D., said during a recent AARP tele-town hall event. "And beyond all of that, we know that COVID has forced many of our kids to miss playdates and time with grandparents, caused them to miss school as well as youth sports. So the cost to our children has been substantial."
Pfizer's vaccine is available for children 5 and older (researchers are still studying the safety and effectiveness of the shots in younger age groups), and so far, millions of children have received at least one dose in the two-dose series. What's more, adolescents 12 and older are now eligible for a booster shot.
Editor’s note: This article was published on March 18, 2021. It has since been updated with new information.