The U.S. Centers for Disease Control and Prevention (CDC) announced new mask guidelines Tuesday to account for the low risk of virus transmission in outdoor settings as a result of increased vaccinations.

"Over the past year we have spent a lot of time telling Americans what they cannot do, what they should not do. Today, I'm going to tell you some of the things you can do if you are fully vaccinated," said CDC director Dr. Rochelle Walensky.

The new rules say it is acceptable to remove masks outdoors and in small gatherings, as long as there is space — regardless of vaccination status.

But many other situations still require masks, especially for unvaccinated individuals.

"I want to be absolutely clear, if you're in a crowd ... you still have to wear a mask. Even if you're outside," President Joe Biden said Tuesday.

Health officials also said Tuesday it is time to remove state-level blanket mask mandates.

"What we're saying is, (for) states that have mask requirements outdoors, if people are vaccinated, we no longer feel that the vaccinated people require masks outdoors," Walensky said.

But the change in guidance comes as the country is experiencing uneven vaccination rates in each state. Walensky said she expects the cases to rise in areas with fewer vaccinated people.

That is something Dr. Ashish Jha, dean of the Brown University School of Public Health, also addressed in a call with reporters Tuesday.

Jha said that while things look bright for the near-term in the U.S., some southern states are a concern due to low vaccination rates. But, he cautioned, defining the areas of low rates by politics or ideology is not helpful.

"The reason why it's slightly wrong ... is what do we know about access in those counties? The higher the barrier, the fewer the people will get vaccinated," Jha said.

So conflating barriers and access into political ideologies like, "Trump supporters aren't getting vaccines," is not helpful, he said.

Jha added that he doesn't believe that the U.S. will need booster shots in 2021, but noted a lot more research vaccine durability.

That contrasts what both Pfizer (PFE) and Moderna (MRNA) CEOs have publicly said.

Moderna CEO Stéphane Bancel told Yahoo Finance earlier this month a booster shot could be likely within a year after vaccination.

Dr. Anthony Fauci has also suggested there could be a need for an additional shot, and that we could know the answer by fall.

More from Anjalee:

• J&J vaccine pause remains, Oxford studies blood clots and COVID-19 vaccines

• China, Russia playing 'greater-than-expected' roles in global pandemic response

• Biden COVID-19 adviser: Vaccine news is great, but we still have a ways to go

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