As the new coronavirus continues to spread, Amazon has cracked down on third-party sellers looking to profit from the outbreak. It removed more than 1 million listings last month that falsely claimed to defend against or cure the illness, as well as tens of thousands of items, such as face masks, that were offered for inflated prices. But the retail giant is confronting more than just an influx of sketchy coronavirus supplies. Its bookstore has become a source of dubious information about the outbreak, and Amazon has quietly begun removing some books about the virus from its virtual shelves.

As several news outlets have noted, Amazon has flooded in recent weeks with books about Covid-19, the disease caused by the novel coronavirus, some of which appear hastily self-published and contain conspiracy theories. At least a few appear to be successful: Last Friday, a self-published book titled Everything About Face Masks and Coronavirus was the top seller in Amazon’s Medical eBooks category, beating mainstream nonfiction titles like John M. Barry’s The Great Influenza, which ranked number two. That same day, however, the book’s listing was taken down. Its author, Dr. Timothy Zahar—a pen name, according to his bio—has no other books currently listed on Amazon.

WIRED found that other coronavirus books called out by reporters have since been taken down as well. When reached for comment, the company declined to answer questions about the removal of individual titles. "Amazon maintains content guidelines for the books it sells, and we continue to evaluate our catalog, listening to customer feedback. We have always required sellers, authors, and publishers to provide accurate information on product detail pages, and we remove those that violate our policies,” a spokesperson said in a statement.

Amazon’s content guidelines for books are short. “As a bookseller, we provide our customers with access to a variety of viewpoints, including books that some customers may find objectionable. That said, we reserve the right not to sell certain content, such as pornography or other inappropriate content,” the company notes on its site. Beyond saying that authors, publishers, and vendors are responsible for ensuring their books don’t violate any laws, the only other guideline is that Amazon may remove books that provide a “poor customer experience.”