The recommendations also say that vaccinated people can come together in the same way - in a single household - with people considered at low-risk for severe disease, such as in the case of vaccinated grandparents visiting healthy children and grandchildren.
The Centers for Disease Control and Prevention announced the guidance Monday.
The guidance is designed to address a growing demand, as more adults have been getting vaccinated and wondering if it gives them greater freedom to visit family members, travel, or do other things like they did before the COVID-19 pandemic swept the world last year.
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"With more and more people vaccinated each day, we are starting to turn a corner," said CDC Director Dr. Rochelle Walensky.
During a press briefing Monday, she called the guidance a "first step" toward restoring normalcy in how people come together. She said more activities would be ok'd for vaccinated individuals once caseloads and deaths decline, more Americans are vaccinated, and as more science emerges on the ability of those who have been vaccinated to get and spread the virus.
The new CDC guidelines come as public health officials, after a few snafus early on, race to vaccinate people as fast as possible. Hundreds were ready to be vaccinated in Philadelphia Monday, lining up outside the Pennsylvania Convention Center.
"I think it's great. I would love to see my family and friends again and feel safe about it for everybody," said Phallon Depante of South Philadelphia.
"Long time coming, this is a year now and you need a vaccine to keep on moving, get the United States back together again, the whole world," said Jeffrey Wilson of Nicetown.
VIDEO: Watch full CDC announcement
The CDC is continuing to recommend that fully vaccinated people still wear well-fitted masks, avoid large gatherings, and physically distance themselves from others when out in public. The CDC also advised vaccinated people to get tested if they develop symptoms that could be related to COVID-19.
The CDC guidance did not speak to people who may have gained some level of immunity from being infected, and recovering from, the coronavirus.
Officials say a person is considered fully vaccinated two weeks after receiving the last required dose of vaccine. About 31 million Americans - or only about 9% of the U.S. population - have been fully vaccinated with a federally authorized COVID-19 vaccine so far, according to the CDC.
Dr. Ali Khan, dean of the University of Nebraska College of Public Health, said the guidance is reasonable in many respects - with the exception of travel.
The CDC did not change its recommendations on travel, which discourages unnecessary travel and calls for getting tested within a few days of the trip. That could seem confusing to vaccinated people hoping to visit family across the country or abroad.
"They need to relax travel for those vaccinated" and to immediately publish electronic standards for documents that show whether a person is fully vaccinated, said Khan, who formerly was a leading CDC disease detective.
The new guidance also says nothing about going to restaurants or other places, even though governors are lifting restrictions on businesses, said Dr. Leana Wen, an emergency physician and public health professor at George Washington University who formerly was Baltimore's health commissioner.
Wen has said the CDC should have had some kind of post-vaccination guidance ready in January, when some people first began to finish their second doses. And she called the guidance that came out Monday "far too cautious."
"The CDC is missing a major opportunity to tie vaccination status with reopening guidance. By coming out with such limited guidance, they are missing the window to influence state and national policy," Wen said, in an email.
President Joe Biden has vowed to have enough vaccine supply for every adult who wants a shot by late May.
-- The Associated Press contributed to this report.