Dr. Nancy Messonnier is the director of the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention (CDC). Her impressive bio lists a number of top positions that she has held in the CDC, and it also notes that she has received multiple awards.

In recent days, Messonnier has taken a leading role in warning the public about the threat that the novel coronavirus strain known as COVID-19 poses to the United States. The Wall Street Journal noted that Messonnier said it was just a question of when coronavirus will circulate in the U.S. The Daily Beast quoted her as saying, “We expect to see more cases of person-to-person spread among close contacts. ... The goal here is to slow entry of this virus into the United States.” CNBC quoted her calling for schools to divide students into smaller groups or to close entirely and conduct courses online. Many other outlets have quoted her as well.

But right-wing media have begun to coalesce around a conspiracy theory that Messonnier’s warning should be disregarded because she is the sister of former Trump appointee Rod Rosenstein. Rosenstein was a frequent target of pro-Trump propagandists for appointing Robert Mueller as a special counsel in the Russia investigation.