(CNN)A maskless Memorial Day weekend is a huge deal. People are traveling, Covid-19 cases are down across most of the country and vaccines have made their way into millions of arms.
And while glimpses of normalcy are exciting to see, one health expert is warning that the millions of people who have not been vaccinated may pose high risks to each other.
Dr. Leana Wen, a CNN medical analyst, said people who are fully vaccinated and are generally healthy "should feel very well protected."
But she offered a more critical insight on those who are not.
"Those who remain at risk are those who are unvaccinated," Wen told CNN on Saturday. "And that includes children who are not yet eligible to be vaccinated as well as adults who just have not been vaccinated yet."
She added that even though 40% of the country is fully vaccinated, the risk remains high because a large portion of the population still hasn't been inoculated. While the number of new Covid-19 cases have dropped significantly, that also means "the virus has fewer places to go."
"And so those people who are unvaccinated are now still at high risk because we do have more transmissible variants, and unfortunately those individuals who don't have immunity are not protected from these variants that can wreak a lot of havoc," Wen explained.
People who are severely immunocompromised and have received a vaccine may also potentially be at risk, she said.
As of Saturday, more than 167 million people in the US -- 50% of the total population -- have received at least one vaccine dose, and more than 134 million people are fully vaccinated, data from the US Centers for Disease Control and Prevention shows.
The current 7-day average of daily new cases in the US is 21,627, a more than 22% decrease from the previous week, according to the CDC.
"Go, get vaccinated, hit the beach. Real simple."
As people get out and about this long weekend, states are jumping at the opportunity to get more vaccine shots into arms.
New Jersey launched a new program, "Shots at the Shore," to incentivize people to take the vaccine.
People who head down to the Jersey shore will have the option to receive any of the three vaccines -- Moderna, Pfizer or Johnson & Johnson -- Gov. Phil Murphy said. Younger people ages 12 to 15 may take the Pfizer shot.