By Trang Do

PHILADELPHIA (CBS) — There is a lot of excitement in Pennsylvania and New Jersey about moving into the next phases of reopening, but experts caution that a resurgence in COVID-19 cases is possible.

New Jersey is poised to reopen its hair and nail salons, barber shops, massage and tattoo parlors on Monday. It’s a move Gov. Phil Murphy considers a huge step in his Road Back plan.

“The salons and barber shops are going to be our first step with largely sedentary indoor openings,” he said.

Philadelphia won’t be far behind. Because of the steep decline in COVID-19 infection rates, city officials plan to allow more businesses to reopen Friday, June 26. They include salons, barber shops and spas, pools and swim clubs and outside sections of zoos.

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“The people of Philadelphia didn’t just flatten the cure, you suppressed the virus and in the process saved thousands of lives,” Health Commissioner Dr. Thomas Farley said Thursday.

Still, officials warn these reopenings do not mean the virus is gone. Even though Pennsylvania Gov. Tom Wolf is allowing Philadelphia and its surrounding suburbs to enter the green phase on Friday, Philadelphia is choosing to remain under the more restrictive yellow phase until July 3.

“We are uniquely at risk for a resurgence of this virus and we don’t want that to happen here,” Farley said.

Infectious disease experts say taking precautions, such as mask wearing and social distancing, remains absolutely necessary as cities and states open back up.

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Appearing on “Meet the Press” on Sunday, Michael Osterholm, director of the Center for Infectious Disease Research and Policy, said he predicts not a resurgence, but an ongoing threat he compared to a forest fire.

“I don’t think we’re going to see one, two and three waves, I think we’re going to see one very, very difficult forest fire of cases,” he said.

Murphy also announced that next Monday, June 29, he will allow shopping malls in New Jersey to reopen with restrictions. Food courts, common seating areas, theatres and arcades inside malls will remain closed.