By CBS3 Staff

PHILADELPHIA (CBS) — Federal health advisors backed the use of COVID-19 booster shots for all adults Friday. Also, Philadelphia announced Friday every city employee must be vaccinated by mid-January.

Just hours after the FDA expanded the Moderna and Pfizer booster shot eligibility to all adults, the CDC advisory panel also gave the green light, “booster shots have demonstrated the ability to safely increase people’s protection against infection and severe outcomes and are an important public health tool to strengthen our defenses against the virus.”

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People 18 and older who’ve received the Moderna or Pfizer vaccine will be allowed to mix and match shots six months after their initial two vaccines.

“I think it’s great news,” Delaware County Health Department Director Melissa Lyon said. “We’ve been watching breakthrough cases of those that have been vaccinated and even waning immunity in our population for 65 and older. We know that a booster is the best strategy.”

Health officials welcome boosters going into the holiday season since there’s been a 35% spike nationwide in new cases in recent weeks and hospitalizations up 6%.

Many of those cases are among vaccinated people who haven’t had boosters.

“Vaccines being the best way for us to prevent the spread of COVID-19,” Philadelphia Chief Administrative Officer Stephanie Tipton said.

Philadelphia Health Commissioner Dr. Cheryl Bettigole says “if everyone who is eligible gets one, children continue to get their vaccines and the last few people who haven’t gotten any doses, get vaccinated, it will go a long way.”

In Philadelphia, a new mandate says all city employees will have to be vaccinated or get an exemption by Jan. 14.

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“We have seen the impacts of COVID on our own workforce, we know that from the experience of other municipalities and organizations that mandate works,” Tipton said.

Non-union city employees have until Dec. 1 to be vaccinated. Unions representing police and firefighters have been against vaccine mandates.

Late Friday afternoon, the FOP’s arbitration panel put a hold on the vaccine mandate. The city says it expected this and looks forward to presenting its case in arbitration.

In South Jersey, booster appointments are being booked quickly in Camden County.

“All geared up and ready to deliver,” Camden County Commissioner Director Louis Cappelli Jr. said. “The number of cases is rising in Camden County and throughout the state. The number of hospitalizations is going up so it’s very important we all take steps to stop the spread of the virus.”

The Delaware Department of Public Health says it applauds the latest federal action saying, “COVID-19 cases are again rising and having this tool in our arsenal can help us in holding off another winter surge that could come with people gathering inside more often as the weather turns colder.”

The CDC is hoping the new widespread booster expansion will be a critical step in fighting COVID-19 for good and are encouraging the 47 million Americans who are not vaccinated to protect themselves too.

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CBS3’s Stephanie Stahl and Kerri Corrado contributed to this report.