It’s Memorial Day Weekend. What’s safe to do?

As the United States marks Memorial Day Weekend and the start of summer, so many people are planning to travel to places they haven’t been in a year, see friends again, and go to baseball games, concerts and more.

With coronavirus infections dropping around the country and more than 50% of adults fully vaccinated, are most activities now safe to do? Can we get together with our extended family and friends? What if we’re vaccinated but some of our loved ones are not—and does it matter if they are adults or children? Are there situations in which we still need to keep our masks on?

It depends, said CNN Medical Analyst Dr. Leana Wen, 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 the author of the forthcoming book “Lifelines: A Doctor’s Journey in the Fight for Public Health.”

We are entering a phase in the pandemic where there is a lot of nuance and few clear-cut answers. The one thing that’s for sure, says Wen, is that vaccination makes everyone safer and everything safer to do. Here’s her advice.

CNN: A lot of families are eager to see one another again. Is it safe to get together indoors if everyone is vaccinated?

Dr. Leana Wen: Yes. Vaccination is the single most important determinant for what activities you can engage in. If you’re fully vaccinated, and everyone else you want to see is also vaccinated, you can certainly see one another in all settings, including indoors, without masks, and with lots of hugs.

CNN: What if you’re vaccinated, but some members of your family aren’t? Is it safe to see them?

Wen: This is a bit less straightforward. Vaccination protects you very well from getting coronavirus. The chance of you becoming infected, even if someone you’re seeing has COVID-19, is very low. The exception is if you are severely immunocompromised—for example, if you have cancer and are on chemotherapy or if you are a transplant patient on immunosuppressant medication.

Let’s say that there’s one other household you’re planning to see that has unvaccinated people—for example, young children who aren’t yet eligible to be vaccinated. You can safely see them, including indoors without masks.

If multiple households are gathering that have unvaccinated people, there is the risk that those who are unvaccinated passing coronavirus to one another. You are still at very low risk yourself, so some people in that position may decide it’s fine to see the other unvaccinated people. Another option is to encourage that such get-togethers take place outdoors, with those unvaccinated wearing masks if they have to be indoors with one another.

CNN: What if the unvaccinated are adults who are refusing to get vaccinated? Would you have dinner indoors with them?

Wen: That depends on you and your risk tolerance. Your risk of getting coronavirus from them is low, because you’re vaccinated and well-protected. That said, the risk is not zero, and especially if you’re a parent of young kids or live with someone who is severely immunocompromised, you may wish to reduce your risk of potentially bringing COVID-19 back to them. The safest activity is still anything outdoors. If you do decide to have an indoor meal and you want to use an abundance of caution, open all the windows and doors, and try to stay distanced from the individuals who are unvaccinated.

CNN: Would you have unvaccinated children or an immunocompromised person dine indoors with other unvaccinated people?

Wen: No, I wouldn’t. I know this could result in some family tensions, but you have to decide for yourself where you draw your line. I personally would not feel comfortable with my unvaccinated kids dining indoors with other unvaccinated children or adults. And I would not advise people who are severely immunocompromised to do this either. The weather is nice in many parts of the country, and I’d strongly urge those unvaccinated or who have less immune protection to only see one another outdoors.

CNN: Would you say the same about groups of people renting a house together, if several people from different households aren’t vaccinated?

Wen: Yes. It’s very hard for people staying together in the same house to avoid coming into close contact and therefore potentially infecting one another. If everyone is vaccinated except for people in one household, that’s very low risk. But if there are multiple households with unvaccinated individuals, there is a risk of those unvaccinated infecting one another. To get together safely, the unvaccinated should ideally quarantine for a week and then test prior to the group all staying together.

CNN: What about people who are planning to travel? What precautions would you recommend?

Wen: Memorial Day travel often involves many crowds of people who come from different parts of the country. There are still areas in the United States that are hotspots, with the risk of new and more contagious variants. I’d advise that if you are in indoor public places with lots of people gathered, wear a mask even if you’re vaccinated. Those who are immunocompromised or not yet vaccinated should double-mask or wear an N95 or KN95 mask. This applies to airports, on airplanes, in train stations, during rest stops, and other crowded, indoor settings.

Also, watch what you’re doing once you get to your destination. Those unvaccinated should particularly be cautious. My kids are not vaccinated, for example, and I wouldn’t bring them to indoor restaurants where there are lots of people, close together, without masks. If they have to come with me to the grocery store or other places with unvaccinated and unmasked people, I’d certainly make sure that they wear masks. In such places, I’d wear a mask too.

CNN: How about a block party or neighborhood get-together?

Wen: These could be fun, and safe! Anything outdoors, I’d feel very comfortable with. I would be fine with my unvaccinated children going without masks to a block party, a picnic in our neighborhood park, or a backyard or porch get-together.

CNN: Does that include the beach or the pool? What if it’s crowded?

Wen: Coronavirus isn’t transmitted through the water, and any outdoor setting is going to be much safer than indoor settings. I’d feel comfortable taking my kids to the beach or an outdoor pool, even if it’s crowded.

CNN: What about a birthday party or wedding where there are some events that are going to be indoors, and I don’t know whether the others are vaccinated?

Wen: This will depend on your comfort level. If you’re fully vaccinated, the risk to you is going to be very low. You could engage in these activities if you choose. Some people will choose to only participate if everyone present is known to be vaccinated; if not, they would participate only in the outdoor components of these activities. You should decide your comfort level and let the host know in advance.

CNN: What if I still want to wear a mask?

Wen: That’s also entirely your choice. The change in mask guidance has been pretty sudden. We’ve been living with masks for 15 months. Some people can’t wait to get rid of their masks, and others still find a lot of comfort in them—and for good reason, because a high-quality mask does protect you, the wearer, from contracting disease.

There are settings in which vaccinated people should still be wearing a mask. There are others where you could, safely, go without a mask, but it’s also entirely reasonable to choose to wear one still.

CNN: There are some people who might be anxious about social interactions over Memorial Day holiday. What’s your advice to them?

Wen: Take things at your own pace. Don’t feel pressured to do something that you’re not ready for yet. Decide what your comfort level is. Maybe you’re comfortable with only seeing those who are fully vaccinated, or only outdoors. That’s OK. Work your way up from a small gathering first. And enjoy! We are finally emerging from the pandemic, and I hope you have a wonderful Memorial Day, whatever activities you choose to engage in.