U.S. public health officials on Friday updated it's mask guidance and is encouraging the public to wear N95 or KN95 masks to slow down the spread of COVID-19.

Those types of masks are considered better at filtering particles. But, when the pandemic first started they were in short supply, and Centers for Disease Control and Prevention officials previously said that they should be prioritized for health care workers.

With this new update, CDC officials have removed any concerns related to supply shortages and clearly have noted that properly fitted N95 and KN95 masks offer the most protection.

The CDC's last mask guidance in September encouraged the use of N95 masks if supplies were available and you were near a lot of people for an extended period of time on a train, bus, or airplane.

On Thursday, President Joe Biden announced that his administration was planning to make "high quality masks" available including N95 masks, for free. He said more details would be shared in the next week. The White House said that the federal government has a stockpile of more than 750 million N95 masks.

The latest guidance also noted that "Surgical N95" masks should continue to be reserved for health care personnel, the agency noted.