Mom warns of COVID-19 misinformation after she says she became anti-vaccine influencer

As experts warn about the spread of COVID-19 misinformation in online parent groups, one mom is speaking out about how she inadvertently became an anti-vaccine influencer.

Heather Simpson of Dallas, Texas, said she turned to wellness groups and became an online influencer almost overnight when she posted anti-vaccine beliefs on Facebook after watching an anti-vaccine documentary.

"I was convinced that if I vaccinated my child, she would die that night," Simpson told "Good Morning America." "That kind of led me into the entire wellness community as a whole."

"At the time, I was a stay at home mom. I was lonely. I didn't have family or friends close by," Simpson continued. "It was so nice to be welcomed into this community. They were listening to your health concerns. They were supportive."

According to a recent study by The George Washington University, parents like Simpson were especially vulnerable to online misinformation campaigns early on during the COVID-19 pandemic. They were exposed to thousands of alternative health and anti-vaccination communities on networking sites like Facebook.

Both the Centers for Disease Control and Prevention and the American Academy of Pediatrics recommend that children ages 5 and older receive vaccinations to protect against COVID-19. CDC data shows that more than 9 million children between the ages of 5 and 11 in the U.S. have received at least one dose of a COVID-19 vaccine and nearly 8 million have received two doses as of April 13.

When Simpson started sharing her own anti-vaccine beliefs online, her posts took off and people shared them hundreds of times.

"People saw me as a health authority," Simpson said. "I could post anything and they're going to share it and take it as fact."

Renee DiResta, a research manager at Stanford University's Internet Observatory who studies disinformation, the deliberate spreading of false information, and social networks online, says it's not hard to end up in so-called wellness groups and they can feel welcoming and supportive.

"You have to know which medical websites to trust. If you're using whatever search engine, you don't necessarily know if you're getting reputable information there," DiResta told "GMA."

"You feel like you're hearing from your friends. You're getting social feedback. Oftentimes, people who are the most passionate about sharing information are not necessarily sharing the right information," DiResta added.

The federal government has warned consumers about disinformation, including taking action against fraudulent products that claim to treat COVID-19. In March, the Department of Justice, Federal Trade Commission and the Food and Drug Administration, sued a marketer of an herbal tea, called Earth Tea, for false advertising.

The company told "GMA" it never promoted Earth Tea as a clinically proven COVID-19 prevention method, treatment or cure, and has stopped advertising and selling products in the U.S.

Simpson said ultimately, it was her concern for her 4-year-old daughter's well-being that led her to change her stance and come to support vaccinations.

"I realized, 'What if she got the measles? What if she did die from the measles and I could have stopped that?'" she recalled.

Now, Simpson has co-founded a vaccine advocacy site, called "Back to the Vax," as well as a podcast and support group.

"I feel like there is a responsibility to listen to the anti-vaxxers and the wellness community and try to bridge the gap," she said.

For credible online sources for medical advice, start with the websites for the CDC and National Institutes of Health (NIH), and ask your health care provider if you're curious or have any questions about wellness products.