What the science says about 7 common COVID-19 vaccine myths

This story is part of Doubting the Dose, a series that examines anti-vaccine sentiment and the role of misinformation in supercharging it. Read more here.

The Pfizer-BioNtech, Moderna, and Johnson & Johnson/Janssen vaccines may be miracles of modern medicine, but they were also developed in a remarkably short time frame, amid a sea of misinformation and conspiracy theories. So it’s understandable that some may feel initially hesitant about getting vaccinated.

While there is an immediate need to get many people vaccinated quickly in order to reduce infection rates and the chance that further dangerous mutations will occur, convincing the vaccine-hesitant may take time.

Best practices for talking about the importance of COVID-19 vaccination include genuinely listening to the concerns that others express and only providing answers you know to be true. If you’re unsure about a fact, it’s fine to say so and to direct the person to a reputable source or do more research yourself.

With all the misinformation floating around, we rounded up seven common vaccine myths that may dissuade people from getting vaccinated. Here’s what the science tells us about the COVID-19 vaccines.

Myth: The vaccines were rushed to market, so we don’t know their long-term impacts.

It’s true that the three COVID-19 vaccines were developed in record time—less than one year versus the usual 10 to 15 years that it usually takes to get a vaccine through the stages of development and testing.

This is because of the severity of the pandemic, the amount of funding the effort received globally, and the dedication of researchers who worked around the clock on this massive undertaking. Rather than cut corners on clinical trials, other aspects of the process were streamlined, such as pre-building manufacturing facilities.

All three vaccines were built on technology that has been in development for years. Pfizer and Moderna both launched mRNA vaccines, which have been in development for decades. mRNA vaccines are also being researched for Zika, flu, rabies, and more, according to the CDC. “They were able to leverage that technology that was used for a different therapeutic use,” Rupali Limaye, a scientist at Johns Hopkins Bloomberg School of Public Health, told Fast Company after approval of the Pfizer and Moderna vaccines earlier this year. Similarly, the Johnson & Johnson vaccine builds on years of research about adenovirus-based vaccines.

It’s unlikely that there are long-term effects of this vaccine that we haven’t seen in trials. “The only long-term effects that have occurred after licensed vaccines are ones we learned about within weeks or months of vaccination,” writes science journalist Tara Haelle in Elemental. “If the COVID-19 vaccine caused long-term effects beyond the side effects reported in the trials, we would know about them by now.”

Myth: Getting the vaccine means getting a small amount of the virus injected.

None of the shots actually give you the SARS-CoV-2 virus, which causes COVID-19. Instead, the approved vaccines work by teaching your body how to make something called a spike protein, which is a protein that’s part of the SARS-CoV-2 virus. This protein triggers your body’s natural immune response. That way, if you’re later exposed to the virus, your body will already be equipped to fight it.

In the case of Pfizer and Moderna, your body is taught this via messenger RNA, or mRNA. The J&J shot accomplishes the same thing via a harmless adenovirus engineered so it contains the genetic information for the spike protein.

Myth: Vaccines can change your DNA.

This sounds like a scary idea, but the mRNA that is used in the Pfizer and Moderna vaccines never interacts with your DNA, and it breaks down quickly once it does its job helping your body develop antibodies to the virus’s spike protein. The Johnson & Johnson vaccine also doesn’t alter your DNA.

Myth: Vaccines can affect your fertility.

In a joint statement, experts from the American College of Obstetricians and Gynecologists, the American Society for Reproductive Medicine, and the Society for Maternal-Fetal Medicine emphasized that there was no evidence of the vaccine affecting fertility, saying, “While fertility was not specifically studied in the clinical trials of the vaccine, no loss of fertility has been reported among trial participants or among the millions who have received the vaccines since their authorization, and no signs of infertility appeared in animal studies. Loss of fertility is scientifically unlikely.”

One way we know this? Rates of vaccine trial participants who got pregnant after being vaccinated were similar to pregnancy rates of trial participants who got the placebo, which suggests getting vaccinated was not detrimental to fertility. Pregnant people are at higher risk for serious illness from COVID-19, however.

Myth: Lots of people are having allergic reactions to the vaccine.

Only an extremely small number of people have had a reaction that was severe enough to require treatment with epinephrine or hospitalization. There’s a system for vaccination providers to report severe reactions, so the CDC is keeping very good records of this. If you have allergies, you should talk with a doctor before getting vaccinated. Side effects are possible, as with any medicine, but the benefits of the vaccine far outweigh the risks.

Myth: The new variants will make the vaccines useless anyway.

While it’s true that some of the new strains of the virus make vaccines less effective, experts still think that vaccination is critical. “Even in years when we don’t get a great match with the flu vaccine, we see some benefit of immunization,” UCLA Health’s Dr. Annabelle De St. Maurice told the Los Angeles Times. “And that’s the same for SARS-CoV-2. Even if the vaccines are less efficient, getting the vaccine is better than not getting the vaccine.”

If and when new mutations make the vaccines substantially less effective, it is possible to update mRNA vaccines quickly. Researchers are already looking into the idea of a third booster shot to better protect people who received the Pfizer or Moderna shot from new and highly transmissible variants. (The Johnson & Johnson vaccine could also be updated, though its design requires a few more steps.)

Myth: Getting vaccinated doesn’t reduce your risk of spreading the virus to others. 

More research is still being done to understand how—and if—vaccinated people can still spread the virus to others, even if they don’t get sick (or only have minor symptoms) themselves. So far, early research from Israel suggests that vaccination greatly reduces the likelihood of asymptomatic transmission of the virus. That’s great news!

Of course, even if the vaccines didn’t reduce the chance you could spread it, it would still be worth protecting yourself. For now, the CDC still recommends wearing masks and continuing to social distance after getting vaccinated in order to protect others. It’s also important to remember that you’re not protected right away; it generally takes around two weeks after vaccination to build sufficient immunity.

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