Writing for the New York Times, Aaron Carroll, a professor of pediatrics at Indiana University, debunks seven of the most common "myths and misconceptions" about coronavirus vaccines that he has heard from patients, friends, and colleagues.

Learn more: Why so many Black patients distrust Covid-19 vaccines (and 3 ways to rebuild their trust)

1. The vaccines can damage fertility, especially among young people

According to Carroll, a doctor in Germany and a former Pfizer employee last year noticed the similarities between the spike protein in the new coronavirus and a protein that's part of a healthy placenta during pregnancy, spurring the hypothesis that antibodies that attack the spike protein could also attack a woman's body while she was pregnant or trying to become pregnant.

However, "there is no evidence that the vaccination leads to antibodies that attack the placenta," Carroll writes, adding that the spike proteins on the virus and on placentas are "distinct."

While he acknowledges that the vaccines haven't been formally tested on pregnant women, Carroll pointed out that Pfizer's vaccine trial included 23 pregnant women, and the only reported adverse effects occurred in the placebo group. Moreover, Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, has noted that more than 10,000 pregnant women have now been vaccinated, and there have "thus far [been] no red flags."

2. Once you receive a vaccine, you can resume life as it was before the pandemic

While the vaccines are "amazing" in countless ways, Carroll writes, experts do not yet know whether the vaccines prevent asymptomatic infections of the new coronavirus—and that means it's possible "that vaccinated people could still become infected, be unaware, and spread the coronavirus to others."

Experts hope to learn soon whether the vaccine can prevent viral spread, and early data is promising, Carroll adds. However, "until we know with greater certainty, we still need everyone—even those who are immunized—to mask up, distance from others, and remain careful," Carroll writes.

3. Once we have herd immunity, the epidemic will be over

Herd immunity will eventually prevent Covid-19 outbreaks from spiraling out of control—but "[n]owhere in the United States are we near" the level of population-wide immune protection required to achieve that effect, Carroll writes.

And even once herd immunity is gained, he explains, Covid-19 will not vanish overnight; it will merely begin to fade, as the coronavirus finds fewer and fewer vulnerable victims to effect. "Herd immunity will signal the beginning of the end of the [epidemic]—not the day we are done with it," Carroll writes.

4. The side effects of the coronavirus vaccines are worse than those of other common vaccines

In trials of the vaccines that have so far been authorized by FDA, the vast majority of participants experienced only minor side effects such as aches, chills, pain, and fever. These are not "worrisome" symptoms, Carroll writes, but rather "signs that your body's immune system is working."

More serious reactions, such as anaphylaxis, were extremely rare. And while isolated cases of more severe adverse events after vaccination, such as death among older, sicker patients, should be looked into, "it's entirely possible that [these events were] a coincidence and not unexpected in that population," Carroll writes.

He adds that while occurrences of Bell's palsy (a temporary, treatable paralysis that ordinarily afflicts half of the face) did seem in clinical trials to arise more frequently among those who received a coronavirus vaccine than a placebo, the rate was still extremely low—lower even than the background level of Bell's palsy that arises in an ordinary year in the general population.

5. The trials were rushed

The coronavirus vaccine trials did progress speedily—but for good reasons that didn't undermine safety, Carroll writes.

Not only were "[m]ore scientists … probably working on this one thing than have ever collectively focused on any one thing in the history of the world," Carroll explains, but there was sustained public investment and "a guaranteed worldwide market." As a result, many companies devoted large amounts of resources into vaccine development.

Moreover, scientists had already completed a great deal of exploratory and preclinical work in response to the related coronavirus that causes severe acute respiratory syndrome, or SARS, Carroll writes.

In addition, Carroll notes that that while the authorization processes for the two Covid-19 vaccines currently available in the United States were "highly accelerated," no steps were skipped. Both vaccines were tested in Phase I, Phase II, and Phase III clinical trials, the last of which involves "thousands to tens of thousands of people," he explains.

6. The vaccines are more dangerous than Covid-19

When people hear about the side effects of a vaccine, some may assume it's better to not get the vaccine, Carroll writes. But that comparison implicitly involves "comparing those risks [of the vaccine] to perfect health instead of to the risk of Covid-19 itself."

And as he points out, "assuming perfect health is unwarranted: Covid is prevalent and dangerous."

7. If a vaccine is just 70% effective, it's not worth it

The vaccines developed by Pfizer and Moderna showed around 95% effectiveness against symptomatic Covid-19, Carroll writes—but even if future vaccines prove somewhat less effective, they could still be potent public health weapons that could help bring the epidemic to an end. For instance, he notes that the polio vaccine was between 80% and 90% effective, "and it changed the world."

"The more people who get vaccinated, the more morbidity and mortality we avoid," Carroll writes. "The best coronavirus vaccine is the one you can get as soon as possible" (Carroll, New York Times, 2/13).

Editor's note: This story has been updated to refer correctly to the affiliation of Aaron Carroll. He is a professor of pediatrics at Indiana University, not the University of Indiana.