CVS, Wawa, and Wegmans joined a list of businesses that are placing signs with the updated mask policies.
The decision for many is based on recent CDC guidance because of low vaccination rates and concerns about the spread of new variants like the delta strain.
During Thursday's COVID-19 briefing at the White House, officials announced they have recorded 864,000 vaccinations, the highest in a day since July 3.
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The first vaccines were administered nearly eight to nine months ago and now health officials are weighing if booster shots will be needed, especially heading into the winter.
The president of Moderna, Dr. Stephen Hoge, spoke on Good Morning America Thursday morning about how their vaccine is faring against the delta variant.
"Really well," said Hoge. "So right after vaccination, there is some real-world evidence coming out from public health officials showing it does protect against delta."
"The concern is, how long does that last?" he added. "Really the winter season, when everyone comes indoors, will be the biggest test."
Hoge also spoke about booster shots and if he feels they are needed.
"The decision is for public officials, not us as a health company," he said. "But we'll prepare options and (we are) preparing options because we think they're needed."
Dr. John Zurlo, an infectious diseases doctor at Jefferson Health who chairs the COVID-19 task force there, explained what exactly a booster shot is.
"Boosters are for individuals who have gotten any kind of vaccine. We think the vaccine perhaps is not working properly after a certain amount of time or maybe they haven't had a good response to the vaccine," Zurlo explained.
"For example we know that for (the common) flu vaccine for older people, people over the age of 65, don't respond as well for the flu vaccine, hence we give them a higher dose of the vaccine because we hope they will have a better response," Zurlo added.
Those who are immunocompromised, the elderly and people with pre-existing conditions would normally benefit from a booster shot. But, it's not clear yet what the guidance will be for the COVID-19 vaccines.
"We might need boosters to provide better immune protection against these variants as they emerge," said Zurlo. "You can see all of those challenges so, at the moment, we still have not conclusively proven that boosters are necessary for any of those circumstances but it's certainly an ongoing question and they may be in our future. Right now, what we think about boosters, is using one of the accrued vaccines - the same ones we've been using - and its simply giving another dose. That's where we are at this point in time."
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Additionally, we asked: what if you receive a booster from a different brand than the initial vaccine you received?
"That's really unanswerable right now," Zurlo said. "We just don't have the data or any kind of recommendation that would answer that question. Once again it's an intriguing possibility that getting a different booster with a different vaccine may provide truly a different boost, but we don't know that for sure yet."