Twitter CEO Jack Dorsey recorded a podcast with a fitness star who recently said that vaccines cause autism

AP Photo/Jose Luis Magana

Twitter CEO Jack Dorsey.

• Twitter CEO Jack Dorsey guested on a podcast with Ben Greenfield, a fitness personality who last month tweeted that vaccines cause autism.
• This a main contention of the "anti-vaxx" movement, which claims that vaccines are harmful.
• The role of social media platforms in spreading anti-vaccination content has been under scrutiny recently due to a spike in measles cases.
• Dorsey praised Greenfield's health knowledge.

Jack Dorsey has appeared as a guest on a podcast with an anti-vaxxer.

The Twitter CEO, who over the past year has been at pains to stress Twitter is doing all it can to fight the tide of misinformation on its platform, recorded a podcast with fitness personality Ben Greenfield.

Greenfield tweeted last month that "vaccines do indeed cause autism," an unfounded theory espoused by the "anti-vaxx" movement. Greenfield also encouraged people to distrust fact-checking website Snopes.

The spread of anti-vaccine messages online has been thrown into sharp relief recently following a spike in measles cases. Facebook announced last week that it will take action by blocking advertisements that contain vaccine misinformation. It also promised to disable the ad accounts of repeat offenders.

YouTube announced last month that it was prohibiting all videos that promote anti-vaccination content from running ads, saying it considers such content to be "dangerous or harmful."

Greenfield said in a tweet that his podcast with Dorsey covers, "advanced stress mitigation tactics, extreme time-saving workouts, DIY cold tubs, hormesis, one-meal-a-day & more." Dorsey replied saying the pair had a "great conversation."

"Appreciate all you do to simplify the mountain of research focused on increasing one's healthspan! Grateful for you," Dorsey added.

A source familiar with the taping told NBC that the topic of vaccinations did not come up. The podcast is due to be released March 23. Twitter was not immediately available for comment.