By Jen Christensen, CNN

(CNN) -- New guidelines from the US Centers for Disease Control and Prevention say people fully vaccinated against Covid-19 can safely visit with other vaccinated people and small groups of unvaccinated people in some circumstances, but there are still important safety precautions needed. The guidelines will be announced at the White House COVID-19 Response Team briefing on Monday.

The CDC defines people who are fully vaccinated as those who are two weeks past their second dose of the Moderna and Pfizer Covid-19 vaccine or two weeks past a single dose of the Johnson & Johnson vaccine.

People who are vaccinated are protected and there is growing evidence that they don't spread Covid-19, but scientists are still trying to understand how long vaccine protection lasts.

"The level of precautions taken should be determined by the characteristics of the unvaccinated people, who remain unprotected against Covid-19," the guidelines said.

The CDC says fully vaccinated people can:

• Visit other vaccinated people indoors without masks or physical distancing
• Visit indoors with unvaccinated people from a single household without masks or physical distancing, if the unvaccinated people are at low risk for severe disease.
• Skip quarantine and testing if exposed to someone who has Covid-19 but are asymptomatic, but should monitor for symptoms for 14 days

However, people who are fully vaccinated still need to take precautions in many scenarios. The guidelines say fully vaccinated people must:

• Wear a mask and keep good physical distance around the unvaccinated who are at increased risk for severe Covid-19, or if the unvaccinated person has a household member who is at higher risk
• Wear masks and physically distance when visiting unvaccinated people who are from multiple households.

In addition, fully vaccinated people should continue basic safety precautions, including: wearing a mask that fits well and keeping physical distance in public; avoiding medium- and large-sized crowds; avoiding poorly ventilated public spaces; washing hands frequently; and getting tested for Covid-19 if they feel sick.

If fully vaccinated people live in a non-health care congregate setting, such as a group home detention facility, they should quarantine for 14 days and get tested if exposed to someone with a suspected or confirmed Covid-19 case.

The guidelines say that the risk of infection in social activities like going to the gym or restaurant is lower for the fully vaccinated, however, people should still take precautions as transmission risk in these settings is higher and increases the more unvaccinated there are there.

The CDC travel recommendations have not changed for the unvaccinated. The guidelines still say that with high case numbers, the CDC recommends that you do not travel at this time.

"The benefits of reducing social isolation and relaxing some measures such as quarantine requirements may outweigh the residual risk of fully vaccinated people becoming ill with Covid-19 or transmitting SARS-CoV-2 to others," the guidelines said. "There are several activities that fully vaccinated people can resume now, at low risk to themselves, while being mindful of the potential risk of transmitting the virus to others."

There are now 30 million people in the United States who are fully vaccinated.

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