Russian journalists who cover Mr. Putin have not seen him up close since March. The few people who meet him face-to-face generally spend as much as two weeks in quarantine first. The president still conducts his meetings with senior officials — including with his cabinet and his Security Council — by video link from a spartan room in his residence outside Moscow, which has been outfitted with Ms. Izranova’s disinfectant tunnel…

Dozens of World War II veterans joined Mr. Putin on the risers in Red Square in June when he presided over a military parade commemorating the 75th anniversary of the Soviet Union’s victory over Nazi Germany. But before being allowed within breathing distance of Mr. Putin, the veterans had to spend two weeks in quarantine at an isolated health resort.

“We went for walks, were bored, sat around and breathed the air,” said Lev Litvinov, a 100-year-old veteran.

The logistics proved so taxing that Mr. Litvinov did not actually make it to the parade.