A conspiracy theory about Microsoft founder Bill Gates and a potential vaccine for the novel coronavirus has been circulating for weeks on social media platforms, getting high engagement numbers, and has since been pushed by both Fox News host Laura Ingraham and a Newsmax correspondent.

As the coronavirus pandemic has spread throughout the United States, Gates, who runs an organization that focuses on public health worldwide and has warned of the threat of epidemics for years, has been leading efforts to and spoken out about finding a vaccine. That has included spending billions of dollars to find a cure via his foundation and doing interviews on shows including Fox News Sunday and The Daily Show about the need for a vaccine.

Gates on March 18 also participated in a Reddit “AMA” (“Ask me anything”) Q&A, where he encouraged a “national tracking system” for the coronavirus and “some digital certificates to show who has recovered or been tested recently or when we have a vaccine who has received it.” Scientific American reported in December that Gates had been funding efforts to create an invisible ink that could go into people’s skin to see who has been vaccinated. A Massachusetts Institute of Technology bioengineer said the ink could provide data that is useful in fighting disease around the world, noting, “If we don’t have good data, it’s really difficult to eradicate disease” (though the outlet also quoted a bioengineering professor admitting it could raise privacy concerns).

During this time, conspiracy theorists, anti-vaxxers, white nationalists, and supporters of the QAnon conspiracy theory have spread a baseless conspiracy theory on multiple social media platforms, far-right sites, and message boards claiming that Gates’ effort to help develop a vaccine is some kind of nefarious attempt to control, follow, or even depopulate the world’s population via a “microchip” of some sort (the “depopulation” claim is based on a major misreading of Gates’ past remarks).

A review by Media Matters found that the conspiracy theory first seemed to gain traction around March 17, when a YouTube video about the virus mischaracterized Gates’ work to develop trackable vaccine data as “implanting everybody with a global ID” and compared it to tattoos on Holocaust victims. The video received more than 120,000 views. On that same day, conspiracy theory outlet Infowars published a piece and video of an Infowars host suggesting Gates was using the situation to “reduce the world’s population,” citing the invisible ink, and tied it to claiming the government would give out a “color-coded wristband that will be used for traveling Americans during an impending COVID-19 lockdown.” The Infowars article subsequently spread in Facebook groups and showed up as a meme on Instagram.