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This year, instead of just thinking about how to stay safe from the coronaviruses, people are also worried about how to avoid the flu and respiratory syncytial virus, or R.S.V.

There is no federal requirement to wear masks on public transportation. There is no suggestion that mandates will be restored despite the fact that cases of the coronaviruses have increased.

According to the Centers for Disease Control and Prevention, it is a good idea to mask up, but not to be required to do so.

The C.D.C recommends that you wear a high-quality mask over your nose and mouth in public transportation.

The T.S.A. screened more than 4.5 million people over the weekend and there are some precautions you can take.

epidemiologists, infectious disease doctors and air-filtration experts said that you should wear a mask while traveling. Even though planes have great filters, you will likely be on crowded planes with other travelers for extended periods of time, increasing the chance of exposure, according to an infectious disease epidemiologist and assistant professor at the George Mason University.

She said, "Now compound this with rapidly rising numbers of Covid, influenza, R.S.V. and seasonal Respiratory Viruses." If you are traveling in a plane, train, bus or boat, you should wear a mask.

ImageIn the center of the photo a dark-haired man wearing a green tee shirt and a black mask checks in at an airline self-service kiosk. Other passengers stand nearby, some of whom are not wearing masks.
The C.D.C. recommends getting tested with a viral test as close to the time of departure as possible (no more than 3 days before travel).Credit...Kamil Krzaczynski/Agence France-Presse — Getty Images
In the center of the photo a dark-haired man wearing a green tee shirt and a black mask checks in at an airline self-service kiosk. Other passengers stand nearby, some of whom are not wearing masks.

Dr. Linsey Marr is a professor of civil and environmental engineering at Virginia Tech and an expert on airborne transmission of Viruses. She said, "Not just on the plane, but in the airports, on buses, transit and everywhere else that you're going in between."

Even if you don't travel, experts say it's still a good idea to wear a mask around a lot of people.

A sore throat was one of the symptoms that Dr. Popescu started to develop. She caught it while flying home from her job.

She said that if you let your guard down you can expose yourself.

The best way to prevent the spread of respiratory viruses is to use a mask.

The flu and R.S.V. can be transmitted in the same way as Covid-19.

During the holidays, it is a good time to remember the three C's: closed spaces, crowded places and close-contact situations, and to wear a mask in each of them.

If you use a high-quality mask, you can still protect yourself from disease even though wearing a mask is the most effective way to stop the spread of a Viruses.

If you want to wear a mask, you should get a high-quality one. She said that it usually means a N95, KN95 or KF94 It's going to be more effective than a cloth mask.

You can wear the same one until you notice that it is dirty, that the straps are loose, or that it is damaged.

You don't have to take a test if you're traveling within the U.S. or abroad. The C.D.C. suggests that you get tested as close to the time of departure as possible. They advise you to delay your travel if you test positive.

If you are traveling and plan to interact with people without a mask, it is a good idea to test before your flight and for a few days after you land. It's really about your risk profile and preference.

If you will be with vulnerable people and if you will be exposed, you should think about how much you interact with others.

Dr. Popescu said that he recommends testing before and during the trip.

U.S. citizens and immigrants don't need to bevaccinated to travel to the U.S. The person is non-U. S citizens and non- U. citizens. To enter the U.S. from the S, immigrants need to show proof of being fully vaccined. There are only limited exceptions. You will need to sign an attestation before you board your flight if you are not fully vaccine free. Depending on the type of exception, you may have to state that you have taken protective measures.

Travelers have to give their contact information to airlines in order to trace their contacts.

It is never too late to get an updated Covid booster, according to two people.

According to most data, a full immune response to a vaccine can take 14 days, but some of our early data shows that people can generate an antibody response in a few days. It is possible to get an early holiday present if you get the boost soon after.

It is possible that the booster could reach efficacy before the 14-day mark because there isn't a lot of data on it. He said that it is easy to get jabbed quickly. It would work if you made an appointment today.

The experts say to think about why you're traveling and take extra precautions. Most people don't need to worry about diseases if they're healthy. At the holidays, we visit with more vulnerable people and older family members, as well as gathering with family.

Dr. Marr will be spending the holidays with her elderly parents, so her family will be taking more precautions, like not visiting crowded indoor spaces before their trip, to make sure they don't spread any illness to them.

She said that they wouldn't go out to any restaurants in that week to make sure they didn't pick up a Viruses.

Hand hygiene and cleaning high-touch surfaces is an important strategy for preventing the spread of the flu and seasonal respiratory viruses. It's a good reminder to keep your hands away from your face.

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