By Andy Sullivan

WASHINGTON (Reuters) - As Washington emerges from its COVID cocoon, with tourists returning to the U.S. Capitol and officials attending a white-tie party that had been scotched for the past two years, the coronavirus is again stalking the halls of power.

At least a half-dozen senior officials, including members of President Joe Biden's Cabinet and lawmakers, have tested positive for COVID-19 in recent days, even as caseloads drop across the country.

Days after the Gridiron dinner, usually a highlight of the Washington social calendar, Attorney General Merrick Garland, Commerce Secretary Gina Raimondo and Democratic Representatives Adam Schiff and Joaquin Castro tested positive.

Guests at the white-tie event were required to show proof of vaccination, but a small number have reported positive tests since then, Gridiron president Tom DeFrank said, adding, We wish them a speedy recovery.

White House staffers, journalists and other officials have also tested positive in recent days, including Justice Department antitrust chief Jonathan Kanter and Democratic Representatives Katherine Clark and Debbie Wasserman Schultz.

Biden, 79, was not at the event. Former President Barack Obama visited Biden at the White House on Tuesday. Obama tested positive in March.

White House spokeswoman Jen Psaki said on Tuesday that everyone who comes in contact with the president is tested beforehand and meetings are often socially distanced. Biden tested negative last week, she said.

The coronavirus has killed at least 979,000 Americans since February 2020.

Deaths and hospitalizations have dropped sharply in recent months, but the new BA.2 Omicron variant now accounts for nearly three out of four cases in the country, according to the U.S. Centers for Disease Control and Prevention.

The latest spate of cases illustrates how it is nearly impossible to avoid the virus entirely, though vaccines, treatments and increasing levels of immunity are making it less likely to cause severe illness, said Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security.

Everybody's going to get this, he said. But I think we've successfully shifted COVID-19 to the mild end of the spectrum.

(Reporting by Andy Sullivan, additional reporting by Caroline Humer, David Shepardson and Diane Bartz; Editing by Scott Malone and Howard Goller)