As the nation’s public health emergency expires on May 11, the United States Centers for Disease Control and Prevention will stop reporting its color-coded Covid-19 Community Levels as a way to track the spread of the infection.

Instead, the CDC will keep tabs on Covid-19 largely by tracking hospitalizations in some areas, according to a source familiar with the agency’s plans.

This is much the same way the agency tracks other respiratory infections, such as the flu.

Hospitalizations are a lagging indicator: it generally takes a person a week to 10 days to be hospitalized with a Covid-19 infection. So the switch may mean that the nation is losing its capacity for the earliest warning of an uptick in spread.

However, wastewater testing in communities and for air travelers will continue and is expected to close some of those early warning gaps.

“We’re not going to lose complete surveillance, but we will lose that hyperlocal sensitivity to it perhaps,” the source said.

The agency could announce the end of its community levels as early as next week, though the timing has not yet been finalized, the person said.

The CDC did not immediately respond to a request for comment.

The agency adopted its Covid-19 Community Levels in late February of 2022. The community levels replaced an older map that color coded counties by the weekly rate of new infections and what percentage of Covid-19 tests were found to be positive.

The new Community Levels shifted the focus to hospitals – how many people were being admitted for Covid-19 and how many beds were left. The model also took into account the weekly rate of new infections in an area.

The impact was immediate. Suddenly areas that had appeared dark red for high transmission on a map turned a less threatening yellow or green. Under the CDC’s new system, masks were no longer recommended for large swaths of the country.

The change in metrics will happen out of necessity, the source said.

The end of the public health emergency will mean that the government no longer has the authority to require labs to report their Covid-19 testing data, which will impact the ability to calculate a metric called percent positivity.

Covid-19 is a reportable condition, so doctors will still have to report cases to public health officials, but the frequency of that reporting may change. New Mexico, for example, has said that it will report its cases on a monthly basis going forward.

“Some of the metrics simply cannot be sustained, because of the change in data reporting,” the person said.

Cases had already become a less reliable way to track community spread as people switched to home testing and infections went unreported to health authorities.

Currently 97% of counties and territories in the US have a low level of Covid-19 in the community, with 79 counties at a medium community level and just 15 counties or districts at a high level.

The number of weekly Covid-19 cases has been on a steady decline since January. More than 88,000 new Covid-19 cases and 1,052 deaths were reported in the US last week, according to CDC data.

Reference：

https://edition.cnn.com/2023/04/28/health/cdc-covid-community-levels/index.html