(CNN) — The US Centers for Disease Control and Prevention will announce new metrics to guide Covid-19 restrictions such as mask-wearing on Friday, according to a senior CDC official.

CDC will hold a news briefing Friday afternoon to discuss changes to Covid-19 metrics.

“It’s time to shift from panic mode to cautiously moving forward,” a CDC scientist who is involved with the process told CNN on Thursday. “We still need to be worried about [Covid] but maybe not all the time.”

The CDC currently advises people who live in counties with substantial or high levels of Covid-19 transmission to wear masks indoors. The agency will not be changing that guidance, but will be changing the way it assesses “community levels of disease,” by shifting from looking at cases alone to looking at “meaningful consequences” of the virus such as hospitalizations, emergency room visits and deaths.

In the current map, 97% of counties are at substantial or high transmission. The scientist said the updated metrics will result in fewer counties at the highest levels of transmission.

“There will probably be more heterogeneity across the country in terms of what is going on with the virus. It will not be a giant crisis across the whole nation like with Delta and Omicron,” the scientist said. “You never know if things will get bad and we’re going to have pick up masking again and we’ll have to socially distance, which we may still continue to have to do in some parts of country, and that will come and go, but it’s not like it was two years ago.”

Guidance about different mitigation measures, such as masking and social distancing, will be based on the levels of disease in an individual county.

“There will be consideration that when you get to this level, you’ll want to consider doing this; when you get to this level, you want to consider doing this,” the CDC scientist said. “Hopefully they’ll be stressing the importance of local health departments making decisions according to local circumstances.”

Changing metrics

The current community transmission map is based on the number of new cases per 100,000 people and the percent of positive tests in the past seven days.

The agency will change this metric for two reasons, the source said. One, many more Americans are vaccinated now. Two, Omicron, the dominant variant in the United States, is much more transmissible and causes much milder illness.

The decision to use case numbers was made earlier in the pandemic, based on the behavior of previous variants.

But the now-dominant Omicron variant acts differently than previous variants, so the federal official said it makes sense to tweak the metrics based on those differences.

The scientist said the CDC now wants to focus more on meaningful consequences such as hospitalizations, emergency room visits and deaths, noting that this is similar to the way the agency monitors influenza.

“Meaningful consequences of the illnesses give us a better impact of Covid on people and the health care system,” the scientist said.

They added that the changes have been in the works for some time.

“This has been something folks have been engaged with and working on very hard — I mean really hard — over the past few weeks,” the scientist said. “It started before Omicron, and then Omicron pulled everyone into it, and now we’ll be able to finish it.”

Several states have announced changes to their Covid-19 restrictions, including easing up on masking requirements, and some governors have asked the CDC for clearer guidance about how to make such decisions.

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