The U.S. Centers for Disease Control and Prevention shortened the recommended quarantine period to seven to 10 days for people in the U.S. who have been exposed to the coronavirus, updating its guidance to reflect scientific findings on the time it takes for infections to develop.

The new recommendation, which the CDC announced Wednesday, lowers the quarantine period from 14 days.

A person can end a self-quarantine at seven days after exposure if they test negative and have no symptoms, the CDC said. Without a test, a person should self-quarantine for 10 days, and monitor themselves an additional four days for symptoms, the agency said.

A 14-day quarantine period is still "the best way to reduce risk",said Henry Walke, incident manager for the CDC's COVID-19 response. The agency considers the shorter periods to be alternatives.

The Wall Street Journal reported on Nov.24 that the CDC was completing recommendations for a new quarantine period of this length, after reviewing studies and its own modeling suggesting that shorter quarantines were possible.

CDC officials also said that people should get tested both one to three days before traveling and three to five days afterwards. 

People should reduce non-essential activities a full seven days after traveling, even with a negative test. If people don't get tested following travel, they should reduce activities for 10 days, the agency said.

(With input from agencies)