AS FAST as the coronavirus has raced around the globe, it has been outpaced by a blinding avalanche of social media sorcery and propaganda related to the pathogen, much of it apparently originating in Russia. As always when it comes to its relations with the West, Moscow’s main currency is disinformation, and it spends lavishly.

A European Union document, obtained by Reuters, finds that Russia’s state-controlled media has used the public health crisis to undertake an ambitious disinformation campaign in the West whose goal is to sow the seeds of panic and distrust. In Washington, a senior State Department official told Congress that bogus online accounts, websites and traditional media outlets, all under the Kremlin’s aegis, have leveraged deepening fears of the pandemic “to try to advance their priorities.”

The falsehoods, conveyed on Twitter and YouTube, among other platforms, blamed the Bill & Melinda Gates Foundation for concocting the virus, or said it was a bioweapon devised by the Pentagon. A U.S. soldier deployed in Lithuania had been hospitalized with the virus, went one phony report. Another had it that the prime minister of Slovakia was infected and had passed it to others at a summit.

An E.U. spokesman said that in peddling such claptrap, Moscow was “playing with people’s lives.” A Russian spokesman, Dmitry Peskov, dismissed the allegations as “probably the result of an anti-Russian obsession.” As it happens, that mirrors the Kremlin’s line on its massive interference in the U.S. presidential election four years ago. When denying, Moscow just digs deeper.

Russia is not the only offender. The spokesman for China’s foreign ministry, Zhao Lijian, has cast doubt on the fact that the virus originated in the Chinese province of Wuhan, suggesting baselessly that it had been introduced there by the U.S. Army. That was evidence-free blather, but let’s be clear: America’s political class is not blameless in that regard. Witness Sen. Tom Cotton, an Arkansas Republican and confidant of President Trump’s, who leaped gleefully into the propaganda wars by amplifying a fringe theory that a high-level lab in Wuhan, where dangerous pathogens are the subject of research, may have been the source of the coronavirus. China’s respected ambassador in Washington, Cui Tiankai, dismissed Mr. Cotton’s dark imaginings as “crazy” and made it clear he regarded Mr. Zhao’s as little better.

The Centers for Disease Control and Prevention, alarmed at the swirl of rumors, unfounded speculation and lies, has pleaded for the public not to share it. Unfortunately, Russia’s meddling in 2016 proved that America is fertile ground for such information wars. To Moscow and other adversaries of the United States, it makes little apparent difference whether an election or a pandemic provides the leverage it seeks to subvert trust, institutions and cohesion. The point is to make a muddle of the truth, to cast suspicion on everything, and to weaken the American body politic with doubt and despair. As a means of attack, that can be as debilitating as a virus.

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