Coronavirus updates: 84% of California population to go on lockdown Sunday night

The Centers for Disease Control and Prevention on Wednesday announced alternatives to its two-week recommended quarantine for people who have been exposed to COVID-19.

Quarantine can now end after 10 days without a test if the individual has not reported any symptoms, or after seven days with a negative COVID-19 test and no reported symptoms, said Henry Walke, the CDC's COVID-19 incident manager.

Walke said the move "may make it easier for people to take this critical public health action by reducing the economic hardship associated with a longer period, especially if they cannot work during that time."

People should continue to monitor for symptoms for the full 14 days after being exposed to the virus "especially if quarantine is discontinued early," he said.

A 14-day quarantine remains the best way to prevent spread, according to the CDC.

Walke added, “Everyone should follow this specific guidance from their local public health authorities about how long they should quarantine.”

-ABC News' Sophie Tatum

In this week's briefing for governors, the White House Coronavirus Task Force urged all Americans over the age of 65 or with significant health conditions to avoid "any indoor public spaces where anyone is unmasked.”

The briefing said those under 40 years old who saw anyone outside their household for Thanksgiving should assume they're infected and must isolate.

“The COVID risk to all Americans is at a historic high," according to the briefing, which was obtained by ABC News. "The national daily COVID incidence after Memorial Day, but before the summer surge, was fewer than 25,000 new cases/day and is now more than 180,000 new cases/day; COVID inpatients then were fewer than 30,000 but are now more than 90,000; fatalities have more than doubled."

"We are in a very dangerous place due to the current, extremely high COVID baseline and limited hospital capacity; a further post-Thanksgiving surge will compromise COVID patient care, as well as medical care overall," the briefing said.

-ABC News' Josh Margolin and Brian Hartman

Russian President Vladimir Putin has asked his deputy prime minister for social policy to begin large-scale COVID-19 vaccinations next week using the Russian-developed Sputnik V vaccine.

Putin said doctors and teachers will be the first to be vaccinated.

Last week, Russia’s health minister said mass vaccination would not start until January or February.

Russia claimed to be the first in the world to register a COVID-19 vaccine in August, approving it even before starting the key Phase III trial.

-ABC News' Patrick Reevell

Dr. Moncef Slaoui, chief science adviser to Operation Warp Speed, said he expects the U.S. Food and Drug Administration "to reach a similar conclusion" to the United Kingdom's approval of a COVID-19 vaccine developed by U.S. pharmaceutical giant Pfizer and its German partner BioNTech.

"I hope by the 10th or 11th of December the Pfizer vaccine is approved," Slaoui told ABC News chief anchor George Stephanopoulos in an interview Wednesday on "Good Morning America."

Slaoui urged Americans to "listen to the experts" and trust the vaccine approval process.

"No corners have been cut," he said. "The [vaccine] development has been done very quickly because we had great science to allow us to do all the discovery work in weeks rather than in years. And then the clinical work, the most important part that demonstrates the effectiveness of the vaccine and its safety, has been done to a higher standard than what's done normally in larger number of people but will be assessed and studied in an ongoing basis."

Slaoui described a vaccine as "an insurance against this virus."

"This is what will get us out of the pandemic," he said.