By Alecia Reid

PHILADELPHIA (CBS) — With more than 200 people hospitalized from COVID in Philadelphia, the city’s acting health commissioner is trying to protect those who remain at risk. Dr. Cheryl Bettigold said Wednesday that infections and vaccine rates are trending in the right direction overall.

However, more work needs to be done.

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“Two-thirds of people diagnosed with COVID were exposed to their own homes by family members, friends, and other visitors. Why? Because home is where we let our guard down,” Philadelphia’s acting health commissioner said.

The city’s top health official said vaccines are part of a layer of protection needed as families send their children back to school. State and education leaders are feeling the pressure to keep students safe.

The worry comes as University of Pennsylvania researchers said the city’s summer vaccine sweepstakes didn’t increase as much vaccination interest.

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“We randomly selected certain zip codes to receive 100 times the odds of wins in the sweepstakes, and we announced those at each drawing that there would be priority zip codes in the next drawing,” Professor Katy Milkman of the Wharton School of the University of Pennsylvania said.

The report can be viewed here. The $50,000 grand prizes only pulled in small numbers. So what works?

“It points to mandates,” Milkman said. “We’re seeing many more employers mandating vaccination.”

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The city’s health department expects 80% of Philadelphia residents to have at least one shot by the end of the week. They estimate 65% to be fully vaccinated.