By Stephanie Stahl

PHILADELPHIA (CBS) — A new warning from Philadelphia health officials as COVID-19 cases begin to increase again. They say people should take precautions and consider wearing masks inside public places.

Health officials are hoping to avoid renewed mandates, but a new wave of COVID-19 could be coming following the surge in Europe. Plus, spring break travel and gatherings could help fuel the spread.

READ MORE: Philadelphia School District Students, Staff To Resume Masking As COVID Cases Continue To Rise In City

It’s been just a month of Philadelphia being in the all-clear of COVID precautions. Infection rates and hospitalizations have been low. But the city is now averaging 94 cases per day over the past two weeks, which is a 50% increase. It’s prompting a new recommendation from the Philadelphia health commissioner.

“Now is the time to start taking precautions,” Health Commissioner Dr. Cheryl Bettigole said. “It’s not required yet, but Philadelphians should strongly consider wearing a mask while in public indoor spaces.”

The city has four-tiered response levels based on case rates, trends and the number of people hospitalized with COVID.

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The current all-clear is the lowest level, but the city is now close to moving into level two, where masks would be required indoors.

“We don’t want to keep masks longer than we have to,” Bettigole said on March 2, when the indoor mask mandate was lifted. “I think we all have to stay alert, you know. We do not know what is happening next. We know that internationally there are large numbers of people who are unvaccinated.”

An outbreak in Shanghai has 26 million residents in lockdown and there are surges in Europe. The U.K. hit a record of nearly 5 million new cases last week.

In the United States, numbers are still low, but case numbers are rising in the northeast as the BA.2 subvariant becomes the dominant, more contagious strain.

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While cases are increasing, the number of Americans getting vaccinated is at an all-time low. That’s adding to the concern about the potential for another surge and new round of restrictions.

Stephanie Stahl