On Friday, the US Centers for Disease Control and Prevention said they found that people who were unvaccinated against COVID-19 were 11 times more likely to die from the virus than those who were fully vaccinated.

In its Morbidity and Mortality Weekly Report, the CDC said that unvaccinated patients were over 10 times more likely to be hospitalized.

According to the study, the CDC analyzed data from more than 600,000 COVID-19 cases in 13 states from April through mid-July.

The study also showed that unvaccinated people were 4.5 times more likely to contract COVID-19 than fully vaccinated people.

"These findings reaffirm the high protection of COVID-19 vaccines against moderate and severe COVID-19 resulting in ED, UC, and hospital visits and underscore the importance of full COVID-19 vaccination and continued benefits of COVID-19 vaccination during Delta variant predominance," the CDC said in its report.

In another study released Friday, the CDC said that the Moderna vaccine was more effective in preventing hospitalizations than the Pfizer-BioNTech and Johnson & Johnson vaccines.

With COVID-19 infections at their highest levels since January and hospitalizations at a level not seen since the winter surge, the Centers for Disease Control and Prevention is recommending indoor masking even for vaccinated people. While new studies show that the COVID-19 vaccines continue to provide excellent protection against severe disease, the data suggest there may be decreased protection against the delta variant.

There are many people who are fully vaccinated and want to be responsible members of society. They are wondering, what can and should they continue to do? What about getting together with friends, dining indoors, and going to the gym? Can vaccinated grandparents still get together with their unvaccinated grandchildren?

To help answer these questions, we spoke with CNN Medical Analyst Dr. Leana Wen. Wen is an emergency physician and visiting professor of health policy and management at the George Washington University Milken Institute School of Public Health. She's also author of a new book, "Lifelines: A Doctor's Journey in the Fight for Public Health."

Q: How should people be thinking differently about risk given the rise in infections and new research?

Dr. Leana Wen: In terms of processing where we are right now, I think people should keep two things in mind. First, most parts of the United States have substantial or high COVID-19 transmission, as defined by the CDC. We need to think about the vaccine as a very good raincoat. If it's drizzling outside — if the level of infection isn't very high — the vaccines will protect very well. But if it's a constant thunderstorm, then there's a higher chance of getting wet. A vaccinated person is at higher risk when surrounded by a lot of people who could be infected with COVID-19, and that's what occurring throughout the U.S. right now.

Second, we are entering a phase in the pandemic where nearly all activities will have some level of risk. People need to decide for themselves what risk they are comfortable with by considering their household's medical circumstances and the value of the activity to them.

If everyone in your household is fully vaccinated and generally healthy, you might be willing to take on more risk. You might conclude that even if a breakthrough infection were to happen, it would probably be mild, and you are OK with taking on that risk in order to continue your pre-pandemic activities. Someone else could decide that, because they live at home with unvaccinated younger children or immunocompromised family members, they want to be more cautious.

I think that both options are equally reasonable. The vast majority of the spread of Covid-19 is by people who are unvaccinated. Vaccinated people are not a threat to public health, and they should be able to exercise their own judgment about what activities are safe enough for them.

Q: Let's go through the risk of specific activities. What's the risk of indoor dining?

Wen: Indoor dining in a restaurant definitely has more risk than dining outdoors. What that risk depends on several factors. For starters, what's the space configuration in the restaurant? A very crowded, poorly ventilated setting will have a higher risk than a venue in which you could spread out from other diners.

Also, who are you dining with? If everyone in your party is known to be fully vaccinated, and these are the only people who will be near you, that is a safer scenario than if members of your own party are unvaccinated. I'd also look at the rate of virus transmission in your community. The lower the rate, the potentially safer it is.

Q: How about going to the gym?

Wen: Again, that depends on the circumstances. If you're using the elliptical or weight machines, and no one is close to you, then it's pretty safe. If you're attending outdoor gym classes, the risk is also low. But if you're going to, say, a high intensity exercise class where a lot of people are breathing heavily, near one another, and you don't know whether they are vaccinated, the risk is substantially higher.

Q: Would you travel?

Wen: The risk of air travel is pretty low and can be reduced further if you are wearing a high-quality mask like an N95 or KN95. The bigger concern is what happens once you get to your destination.

Q: What about a private gathering with friends where everyone is vaccinated? Would it be OK to continue dinner parties and other indoor get-togethers?

Wen: That will certainly be a lot lower risk than if the same people were together, but they were unvaccinated. A CDC study this week found that those who are unvaccinated have five times the rate of getting COVID-19 than the vaccinated (and a 29-times higher likelihood of being hospitalized or dying from coronavirus).

A lot of vaccinated people would feel comfortable with the level of risk in this situation. Again, it's not zero, but it's fairly low. That's particularly true if the other people at the gathering have a similar level of risk tolerance to you and are otherwise not engaging in high-risk activities — for example, if they always wear masks when in indoor public spaces and if they avoid higher-risk exposures such as crowded bars and restaurants.

Q: Last fall and winter, people formed pandemic pods. Would you recommend doing this again?

Wen: For some people, yes, I would. There are many people who really want to minimize the chance of having a breakthrough infection. That includes individuals who have underlying medical conditions, where a breakthrough infection that's mild for someone else could land them in the hospital. Others might be pretty healthy themselves, but don't want to be asymptomatic carriers who could transmit COVID-19 to their vulnerable family members. People in similar situations, who have a similar approach when it comes to caution in their lives, could decide to form a pandemic pod with one another. They could decide to socialize only others in the same pod indoors.

My family has done this with another family that has young, unvaccinated children. That makes childcare, carpooling and playdates easier. I'd also advise others to consider the level of caution other households have before deciding to get together indoors with them. When in doubt, get together outdoors only.

Q: Can vaccinated grandparents still be getting together with their unvaccinated grandchildren?

Wen: Yes. I'd advise grandparents who are concerned about transmitting COVID-19 to their unvaccinated grandchildren can choose to reduce their own risk in the three to five days prior to seeing their grandkids. They could refrain from indoor get-togethers with others during this period, and, if they want to be extra safe, I'd suggest that they get tested just before seeing their grandkids.

My advice is the same the other way around, for the grandkids, if grandparents are particularly vulnerable. The grandkids can always make sure to wear masks indoors around others in the three to five days prior to getting together and then getting tested before the reunion.

If all of this is too much, consider seeing one another outdoors only. Outdoors remains much safer than indoors. And, of course, if there are any individuals age 12 and above who are not yet vaccinated, they should do so as soon as possible, to protect them and others around them.

Ohio isn’t tracking the number of fully vaccinated people who have contracted COVID-19. Instead, the state collects data about how many people with these “breakthrough” infections have been hospitalized or died.

At first glance, it may seem like something here is missing, but Ohio’s chief medical officer says less is actually more. He also said the CDC takes the same approach.

“When you think about this from an information- or data-gathering point of view, it is much more reliable to look at those endpoints of hospitalizations and deaths,” Dr. Bruce Vanderhoff said. “Endpoints which really and truly tell us if the vaccination is doing what it was designed to do or not.”

Indiana is taking a different approach. The state tracks the number of breakthroughs to compile a total number of cases, but the method is somewhat non-traditional.

The data is pieced together in a painstaking way by comparing two separate databases. Staff members look at a registry of every vaccinated Hoosier and a spreadsheet of daily positive COVID test results. Then they crunch the numbers and post weekly totals for the public online.

Dr. Thom Huth, who works for Reid Health in Wayne County, Indiana, said he can see how having separate ways to track these cases can be confusing.

"It unfortunately may create the impression that authorities don't know what they're doing,” Huth said. “But that's not the case. It's just that the needs are changing so quickly. It's hard for anybody to keep up.”

He also said tracking individual breakthrough cases is tricky and can be unreliable.

"One recent day, 10% to 15% of the patients in the hospital had been previously vaccinated,” Huth said. "But that number goes up and down."

Ohio Governor Mike DeWine said he supports the way Ohio gathers its data on these breakthrough cases and fear of discouraging vaccination plays no part in how the state collects numbers. DeWine said top health advisors, including those at the CDC, think it’s more important to track hospitalizations and deaths of fully vaccinated people.

Dewine said the focus should remain on boosting vaccination numbers, a sentiment former Cincinnati health commissioner Dr. O’dell Owens agrees with.

"The key part is to keep people out of the hospital,” Owens said. “We’ve got to stay focused on one thing. If everybody's vaccinated, there are no breakthrough cases.”

More than half of the United States population older than 18 have been fully vaccinated against COVID-19.

That's according to data kept by the Centers for Disease Control and Prevention.

This comes just six weeks before President Joe Biden's goal of having 70% of the U.S. adult population with at least one shot by July 4.

According to Johns Hopkins University data, more than 33.1 million confirmed coronavirus cases and 590,000 deaths were reported in the U.S.

More than 359 million vaccine doses have been distributed nationwide, and more than 287.7 million administered CDC data shows.

According to the CDC, more than 131 million people over 12 have been fully vaccinated.

The CDC reported Alaska, California, Colorado, Connecticut, Delaware, Hawaii, Iowa, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, New Hampshire, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, South Dakota, Vermont, Virginia, Washington, and Wisconsin, have fully vaccinated at least half of their adult residents.

Connecticut, Maine, Massachusetts, and Vermont have fully vaccinated more than half of their total resident population, the CDC reported.