By Stephanie Stahl

PHILADELPHIA (CBS) — The road to recovery turns green tomorrow. After more than three months in different phases of lockdown, southeastern Pennsylvania will be back in business with the lifting of most restrictions.

Health officials are urging caution, warning we could see a resurgence of COVID-19 if people aren’t careful.

Pennsylvania Secretary of Health Dr. Rachel Levine says green doesn’t mean returning to normal. As the Philadelphia region reopens, people still need to take precautions.

After 100 days of restrictions to contain the spread of COVID-19, southeastern Pennsylvania will go from the yellow phase of reopening to green on Friday.

The move comes because of a continued downward trend in new cases.

“With the governor’s very careful phased opening approach — the red, yellow, green scheme — we have been able to prevent any significant increases,” Levine said.

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In an exclusive interview, the secretary of health said masks are the key to a successful reopening.

“Masks have been shown to be very helpful in terms of preventing community spread,” Levine said.

But the virus is spreading in many other parts of the country, including record highs in Florida, Texas, and California.

“Big metro areas seem to be rising very quickly and some of the models are on the verge of being apocalyptic,” infectious disease expert Dr. Peter Hotez said.

Considering the spikes in other parts of the country, is Levine worried about that happening here?

“I am always concerned about it actually, 24/7,” Levine said. “The best ways for that not to happen are for people to be alert and vigilant, for people to wear masks, wash their hands and continue to social distance.”

But the trend has been for cases to increase as restrictions are lifted and people start interacting.

Levine says the way to prevent that is through expanded testing, where infected people are isolated quickly along with their contacts.

If that doesn’t work could red or yellow restrictions be reimposed?

“We’re confident that our containment strategy will work and we do not plan at this time to have counties, for instance, go back in terms of the color scheme,” Levine said.

While Philadelphia will be in the green phase tomorrow, only a limited number of businesses can open, like hair salons. The city has decided to keep restrictions in place for another week.

Stephanie Stahl