By Katia Hetter, CNN

Families all over the world are gathering to celebrate Hanukkah, Christmas, Kwanzaa, New Year's Eve and other winter holidays.

Unfortunately, these celebrations are taking place during multiple viral surges.

For weeks, children's hospitals have been overwhelmed due to an earlier-than-usual rise in respiratory syncytial virus (RSV) and influenza. COVID-19 cases are on the rise, too, and a CNN analysis showed that hospitals are at higher capacity now than they have been throughout the coronavirus pandemic.

What can families do in advance of holiday gatherings and what measures can they implement during the festivities to keep viruses at bay? When should everyone wear masks? How can people reduce the risk of getting sick on flights and during transit? Who might want to consider postponing travel and holiday celebrations? And what should people do if they do become ill after gatherings?

CNN Medical Analyst Dr. Leana Wen, an emergency physician, public health expert and professor of health policy and management at the George Washington University Milken Institute School of Public Health is answering some questions about staying healthy this holiday season.

Q: What can families do now to preserve their holiday get-togethers as much as possible?

Wen: It's always important to stay healthy, and particularly so before the holidays. Even if people aren't so concerned about getting ill, no one wants to become infected just before a long-awaited holiday get-together and have to miss events for fear of transmitting viruses to elderly loved ones and other high-risk family and friends.

My advice is to first identify which gatherings are most important for you to attend. Count backward from the first of these events. For about five days to a week before that first event, try to reduce your risk of catching respiratory viruses as much as possible.

That includes frequent handwashing, especially after touching frequently used surfaces. Wear a high-quality N95 or equivalent mask in all indoor crowded settings. And try to reduce unmasked social gatherings during this period.

Triple threat: Flu, COVID-19 and RSV wreaking havoc before holiday travel
If you have not already received the flu vaccine or the updated COVID-19 booster, do not delay. The vaccines reach optimal protection about two weeks after the inoculation, but even if it's a little bit less than that until your events, there will still be some additional protection.

I'd also encourage you to have a discussion with all the households that are getting together with you. Ideally, everyone who is gathering should reduce their risk, too. If there are vulnerable individuals expected at the gatherings, everyone should agree not to attend if they develop symptoms like fever and coughing.

Q: What measures can help keep viruses at bay during the gatherings?

Wen: Many respiratory infections like influenza, RSV and the common cold are primarily spread through droplets. Droplets are expelled when someone coughs or sneezes. This is why encouraging people not to attend if they are symptomatic is important, and so is good hand hygiene.

The coronavirus is airborne and spread through aerosols, which are tiny, microscopic droplets. Good ventilation helps to reduce the spread of COVID-19 and other respiratory viruses. If you live in a warm weather environment, consider hosting your gathering outdoors — that will be lower risk than indoors.

If outdoors is not possible, consider your setting. Can you choose a larger space where people don't need to cluster very close together? Can you keep some windows and doors open, and run HEPA filters for improved ventilation?

For COVID-19 specifically, having everyone take a rapid home antigen test the same day as the gathering can also reduce risk. You may choose to provide the tests at the door to better ensure that everyone takes one.

Wearing a mask also reduces risk, too. Some people, especially if they are immunocompromised or have other chronic underlying conditions, may wish to mask during the gathering, though this is often challenging when food and drinks are involved.

Q: A lot of people need to travel to be with their loved ones. What can be done to reduce the risk of getting sick on flights and during transit?

Wen: Expect that airports, train stations and bus depots will be quite crowded during the holidays and plan ahead to reduce your risk in these crowds. If your goal is to keep safe during the holidays, I highly recommend masking in these settings. Even if you have returned to pre-pandemic activities and stopped masking months ago, I think it's a good idea to get your mask back out in these crowds so that you don't become sick and end up having to miss holiday gatherings.

High-quality respiratory masks, such as N95, KN95 or KF94, are very protective against droplets. Figure out, if you have not already, which masks you can wear comfortably for long periods of time during transit. Bring several with you in case one of them gets soiled or bent out of shape.

I encourage you to wear masks the whole time while traveling around a lot of people. If you find masks uncomfortable, at least wear them during the highest risk settings — for example, when packed together with dozens of other people waiting to board the plane.

Q: Who might want to consider postponing travel and/or holiday celebrations?

Wen: The threat of respiratory infections requires weighing risks and benefits. For most generally healthy people, especially if they are vaccinated against the flu and COVID-19, the benefits of holiday gatherings — including the socialization and mental health benefits — will far outweigh potential risks.

The calculation may be different for some individuals who are particularly vulnerable to severe outcomes. These individuals may need to gauge each event separately. A small gathering with relatives who all took precautions in advance, who are doing a Covid-19 test at the door, and who are seeing one another in a well-ventilated space is much lower risk compared with, say, a New Year's Eve celebration with hundreds of people who have not taken precautions.

Travel is generally not the major concern; one-way masking with a high-quality mask works very well to protect the wearer. I'm much more concerned about the risk of the gathering once people are together.

People who are particularly vulnerable should clarify the precautions in advance with the hosts. Importantly, they should feel empowered to leave if the event turns out to be higher risk than they anticipated.

Q: What should people do if they do become ill while traveling?

Wen: This is a very important point. Everyone should have a plan for what happens if they develop a viral illness while traveling. The U.S. Centers for Disease Control and Prevention has a checklist of what a COVID-19 plan looks like. That includes, for example, making sure you have enough home tests, speaking with your doctor to know if you are high-risk, and having a plan for treatment, including with the antiviral medication Paxlovid.

Since it's not just COVID-19 that's circulating, also have a plan for what happens if you or someone in your party develops the flu or other respiratory infections. Do you know where you can isolate if needed? What if a young child becomes ill — will you be able to quarantine with your child and then take time off from work if necessary?

This holiday season, there are a lot of circulating viruses, but we also have many tools that help to reduce the risk of contracting them and becoming severely ill. Using these tools helps to keep us healthy, and allows us to keep viruses from interfering with our holiday celebrations.