Biden said COVID vaccine misinformation on social media is ‘killing people.' These are the biggest myths spreading online.

Half of all Americans are fully vaccinated against COVID-19, but health officials say misinformation continues to hinder vaccination efforts and are calling on social media companies to do more to address it.

“They’re killing people,” President Joe Biden said when asked by NBC News what his message is to platforms such as Facebook. “The only pandemic we have is among the unvaccinated. And they’re killing people.”

In a statement, Facebook said the company won’t be “distracted by accusations which aren’t supported by the facts.” Biden clarified Monday that his comments were directed at those spreading falsehoods about the vaccine on social media platforms.

Health experts agree more needs to be done to combat misinformation online.

“They have to support us,” said Dr. Ricardo Correa, associate professor at the University of Arizona College of Medicine in Phoenix, who helps lead a Spanish-language vaccine campaign called “¡Vacúnate ya!”

These are biggest myths about the COVID-19 vaccine circulating on social media and why they’re false:

Does the vaccine change your DNA?

A May 26 Facebook post, which includes quotes but cites no sources, claims Moderna’s chief medical officer, Tal Zaks, said messenger RNA vaccines – such as Moderna's and Pfizer-BioNTech's COVID-19 vaccines – alter a recipient’s DNA.

Other posts from Instagram and Facebook make the same claim and link to an article with the headline “Bombshell: Moderna Chief Medical Officer Admits mRNA Alters DNA.”

But Zaks never made that claim, and mRNA vaccines do not alter the DNA of those who receive them.

Fact check: Moderna executive did not say mRNA vaccines alter recipient's DNA

“It’s impossible that an RNA vaccine affects the DNA,” Correa said.

Messenger RNA is a genetic code that gives instructions to cells to make SARS-CoV-2’s spike protein. The body’s immune system creates antibodies in response to the spiked protein, which will attack the virus if it enters the body.

Because mRNA is not the same as the DNA contained in the nucleus of human cells, it can’t be combined to alter someone’s genes.

Messenger RNA is an amino acid, Correa said, which means it dissolves after delivering instructions to a host cell and leaves the body through the elimination system.

Do COVID-19 vaccines make you infertile?

The idea that the COVID-19 vaccine could cause infertility in women originated from an article titled “Head of Pfizer Research: Covid Vaccine is Female Sterilization,” published on a blog called “Health and Money News.”

The post claims that “the vaccine contains a spike protein called syncytin-1, vital for formation of human placenta in women” and that “the vaccine works so that we form an immune response AGAINST the spike protein ... training the female body to attack syncytin-1, which could lead to infertility in women.”

That is false. Experts say the coronavirus's spike protein is not the same protein that helps form the placenta in a woman’s body.

A small part of the coronavirus spike protein and the syncytin-1 that is vital to the placenta look similar, but it’s too small to have any consequence, virology professor Ian Jones of the University of Reading in the U.K. told FullFact.org, a registered charity and nonprofit company from England that fact-checks and debunks false or misleading claims.

More: No, the COVID-19 vaccine doesn’t cause infertility in women

More: Does COVID-19 vaccine cause infertility in men? Study shows mRNA vaccines do not decrease sperm count

"It's very unlikely that the immune system will confuse these two because it’s a very small part of the molecule," said Dr. Mary Jane Minkin, OB-GYN and clinical professor of obstetrics and gynecology at the Yale School of Medicine. "They don’t look similar enough that the body would create an antibody to attack it."

Pfizer spokeswoman Jerica Pitts confirmed to The Associated Press that the vaccine has not been found to cause infertility or sterilization.

“It has been incorrectly suggested that COVID-19 vaccines will cause infertility because of a shared amino acid sequence in the spike protein of SARS-CoV-2 and a placental protein,” she said in an email. “The sequence, however, is too short to plausibly give rise to autoimmunity.”

Men's fertility isn't affected by the COVID-19 vaccines, either. In a June study published in JAMA Network, researchers at the University of Miami examined semen samples taken before and after participants were vaccinated.

Scientists analyzed semen volume, sperm concentration, sperm motility and total sperm count and found no significant decrease in any of those parameters compared with the samples taken before the COVID-19 shots.

Are the side effects of COVID-19 vaccines worse than the disease?

The U.S. Centers for Disease Control and Prevention say common side effects of the COVID-19 vaccine include tiredness, headache, muscle pain, chills, fever and nausea. People may also experience pain, redness or swelling at the injection site.

Correa said side effects usually don’t last more than 36 hours. However, COVID-19 symptoms typically appear two to 14 days after exposure and may last more than two weeks.

“This (myth) is totally absurd,” he said. “Side effects of the vaccine are limited and mean to a certain point that your immune system is responding.”

COVID vaccine side effects: They mean 'your body responded the way it's supposed to,' experts say

The symptoms of the disease can go way beyond the usual side effects of the vaccine. COVID-19 patients can suffer from pneumonia, strokes, neurological damage, chronic migraines, anxiety, sleep insomnia, and post-traumatic stress disorder.

A person is also 17 times more likely to get a blood clot from COVID-19 than from the Johnson & Johnson vaccine, where the odds are only .0004%, Correa said.

Health experts add that some people also suffer from post-acute sequelae of SARS-CoV-2, commonly known as “long COVID,” in which patients experience symptoms months to a year after the initial infection.

Is there a chip in the COVID-19 vaccines?

A May 10 Instagram post from an account called Keep_Canada_Free shows a video of an unidentified masked woman demonstrating with a small silver magnet that appears to stick to one arm, where she supposedly received the Pfizer shot, but not her other arm.

“You go figure it out. We’re chipped,” she tells her viewers.

The 25-second video had been shared on social media platforms such as Twitter, where a resized version posted on May 8 includes the claim that the vaccine has "magnetic reactions."

Although the validity of the video is unclear, and the account did not respond to USA TODAY’s request for comment in May, health experts say one thing is certain: The COVID-19 vaccines don’t cause magnetic reactions or contain tracking devices.

Fact check: COVID-19 vaccines don't cause magnetic reactions or contain tracking devices

'Nothing too surprising there': Pfizer's COVID-19 vaccine ingredients are pretty standard, experts say

“There’s no way there’s a component that could be a magnet in there,” Correa said. “All the components are very straightforward.”

In a letter to the FDA, Pfizer listed the ingredients in its vaccine. They can be organized into four basic categories:

Active ingredient

  • 30 mcg of a nucleosidemodified messenger RNA (modRNA) encoding the viral spike (S) glycoprotein of SARS-CoV-2.

Fats

  • lipids (0.43 mg (4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), 0.05 mg 2[(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 0.09 mg 1,2-distearoyl-sn-glycero-3- phosphocholine, and 0.2 mg cholesterol)

Salts

  • 0.01 mg potassium chloride

  • 0.01 mg monobasic potassium phosphate

  • 0.36 mg sodium chloride

  • 0.07 mg dibasic sodium phosphate dihydrate

Sugar

  • 6 mg sucrose

"It’s a normal way of packaging up medications for people," Dr. Matthew Heinz, a hospitalist based in Tucson, Arizona, said in December. “That’s just pretty basic chemistry."

Contributing: Adrienne Dunn and Miriam Fauzia, USA TODAY. Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.

Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.

This article originally appeared on USA TODAY: COVID vaccine myths on Facebook, Instagram, Twitter that aren't true