Influencers are using their voices and their platforms to encourage Americans to get vaccinated.

According to data from AI analytics platform HypeAuditor, nearly 9,000 influencers across the U.S. have posted almost 14,000 times about the vaccine between January and August. Influencers are defined as having an authentic following of more than 1,000 people.

The platform analyzed posts that encouraged people to get vaccinated by looking at Instagram data associated with hashtags including #vaccinated, #getvaccinated, #vaccineswork, #fullyvaccinated and #getthevax. The posts reached a cumulative audience of 60.9 million people.

Influencers ranged from the well-known, such as actor Reese Witherspoon and media mogul Oprah Winfrey, to those deemed nano-influencers, who have a follower count between 1,000 and 10,000 people. While celebrities like Witherspoon, Winfrey and actors Ross Butler and Sophia Bush have an estimated reach in the hundreds of thousands or even millions, nano-influencers actually comprised a larger percentage of the group.

Nano-influencers made up 58% of the posts identified, and women between the ages of 25 and 44 made up 43%. Yet it wasn’t just celebrities and nano-influencers either: Dr. Mike Varshavski, known as Dr. Mike on Instagram, was the influencer with the third-highest reach for his vaccination posts, reaching an estimated 1.1 million people.

HypeAuditor provides AI-powered analytics and reporting for Instagram, TikTok and YouTube, identifying behavioral patterns and fake followers and determining engagement on influencer accounts and sponsored posts. Dior, L’Oréal and Unilever are among its customers.

This story originally appeared in PRWeek.