Facebook and other social media have been under scrutiny for vaccine misinformation, but local outlets have also sometimes been active.

The author was Joseph Mercola, who researchers and regulators have said is a top spreader of misleading Covid-19 information. In the article, Dr. Mercola inaccurately likened the vaccines to "gene therapy" and argued against their usefulness.

A month later, The Freedom's Phoenix and The Atlanta Business Journal also published another article by Dr. Mercola. This time, he blamed the billionaire Bill Gates for the pandemic, claiming Mr. Gates had "shadow control" of the World Health Organization.

Facebook and other social platforms have in recent weeks attracted attention for vaccine misinformation, as Covid cases surge from the infectious Delta variant and vaccination rates slow. But The Freedom's Phoenix and The Atlanta Business Journal are two small publications — along with dozens of radio and television stations, and podcasts aimed at local audiences — that have also become powerful conduits for anti-vaccine messaging, researchers said.