Dr. Anthony Fauci has been the United States’ most visible expert during the COVID-19 pandemic, and one of the few (only?) voices during Donald Trump's now-daily briefings to continue to provide no-nonsense, factual information about the virus' spread—even when that information contradicted Trump's own pronouncements.
The Washington Post is reporting that Fauci is now facing "growing threats to his personal safety," and that the Department of Health and Human Services is now increasing security around Dr. Fauci in response.
While the Post says the move was prompted both by threats and "unwelcome communications from fervent admirers," Fauci has been a regular target of right-wing pundits who have attacked him for his frequent contradictions of what Dear Leader has to say. When Trump claimed that a vaccine for the virus would be available "soon," Fauci reconfirmed that it would likely take 12 to 18 months at best. When Trump theorized that perhaps this would all go away again in "April," Fauci was unwilling to peddle such absurdities. When Trump claimed a new drug cocktail was possibly a wonder cure, Fauci noted that it possibly wasn't.
These outrages have led to the typical "conservative" response, in which Dear Leader-obsessed sites run by malevolent yokels have called Fauci an agent of the "Deep State," a Hillary-praiser, and otherwise heaped scorn on the book-learner.
It also led to criticism from Fox News, with host Steve Hilton bashing Fauci for his shelter-in-place advocacy during the network's efforts to prop up Trump's recent but now-abandoned declarations that the economic damage of business closures represented a "cure" that was "worse than the disease."
So it's not surprising that a very visible public figure known for contradicting Donald Trump's claims is facing heightened security risks. It has happened repeatedly, with targets shifting according to Trump’s own grievances and perceived threats.