This map is the key to when US might start easing Covid-19 restrictions

(CNN)There is now more optimism that the worst of the coronavirus pandemic may be ending -- and as other nations lift certain Covid-19 restrictions, some public health experts question whether US counties and cities should consider easing their guidance on mask-wearing or social distancing, as well.

But others warn not to relax such measures too soon.

Denmark has decided to lift all Covid-19 restrictions within the country, Prime Minister Mette Frederiksen announced Wednesday evening, adding that Covid-19 "should no longer be categorized as a socially critical sickness."

"Denmark will be completely open from 1 February," Frederiksen said. "Tonight we can start lowering our shoulders and find our smiles again.

"The pandemic is still here, but with what we know now, we dare to believe that we are through the critical phase," Frederiksen added, highlighting the success of Denmark's vaccination program and booster shots.

In the United Kingdom, people in England no longer have to show their Covid-19 vaccination passes to get into nightclubs and other large venues. Masks aren't required in any public places, although they remain recommended on public transport. Wales, Scotland and Northern Ireland are also easing their restrictions.

But in the United States, "we know there is still much to be done to stop the spread of COVID-19 and end the pandemic. We are still seeing far too many new cases, hospitalizations, and deaths," Kristen Nordlund, a spokesperson for the US Centers for Disease Control and Prevention, wrote in an email to CNN on Friday.

The US daily average of cases is near 500,000, with more than 1,000 deaths, according to the CDC, which encourages everyone to get vaccinated and boosted if they're eligible.

"As we look forward to the spring, it's important to continue practicing prevention measures that we know work -- vaccinating, wearing a mask in public, indoor settings, staying home when you are sick, and washing your hands frequently," Nordlund wrote.

Many US counties and cities rely on coronavirus transmission rates to determine when or if to ease restrictions and recommendations -- and nearly every single county is still experiencing high levels of spread.