Holiday travel suddenly feels more fraught as the world waits for emerging information on the new coronavirus variant. Scientists are racing to see if the current vaccines offer protection against omicron, but many families and other travelers may need to consider a variety of factors now before embarking to see relatives or to experience a change of scenery.

"Once again they will have to make informed decisions," said Dr. Kathy Risse, a pediatrician in Seattle. But unlike last year's holiday period, Risse said, "we know so much more about stopping transmission, and widespread testing is up and running."

For those planning to travel, the basics for protection — vaccinations, masks and social distancing — will help make the trip safer. Here are answers to some of the most pressing travel questions for now.

What are the travel rules if we are going to another state?

Currently there are no vaccine, testing or quarantine requirements to travel within the United States — except Hawaii. Hawaii requires a 10-day quarantine for domestic travelers if they do not show proof of vaccination or negative results from a test taken no more than 72 hours before arrival.

Masks are still required by the Transportation Security Administration for passengers age 2 and up on planes, trains and buses. Different states, and even cities, may have their own mask, testing or vaccine requirements for activities such as indoor dining.

Local health department sites or the AARP website are good starting places to research a state's coronavirus rules.

Do you have to be vaccinated to fly domestically?

Again no, but CDC guidelines recommend that people delay travel until they are fully vaccinated.

Can we still go abroad?

Current CDC guidance does not recommend international travel if you are not vaccinated. If you choose to travel overseas, it can be complicated: Your desired destination may have rules and guidelines that differ from those of the United States. Mexico, for instance, does not require vaccinations or testing for entry, regardless of the traveler's nationality. To visit Canada, foreign visitors must show proof of vaccination and the negative results of a PCR or nucleic acid test. (Unvaccinated children can accompany vaccinated adults into Canada but must follow a specific set of protocols, including health questionnaires and a virus test.)

Rules for these and other countries can change at any time, so it's best to keep checking official government websites as your travel date approaches.

Do you have to be vaccinated to fly internationally?

Again, it's complicated. For outbound travel from the United States, vaccination requirements depend on your destination. U.S. embassy sites are good sources of information, as are countries' tourist and health sites for your desired destination. Age requirements can also vary by destination.

U.S. citizens do not have to be vaccinated to travel back to the United States.

What are the testing requirements for flying into the U.S.?

The United States recently changed the timing of its testing requirement to reenter the country. Travelers must now submit a negative virus test result taken within one day of the flight's departure, instead of the previous three-day requirement for vaccinated fliers. This applies to all travelers age 2 and up, regardless of nationality or vaccination status.

It is important to note that the requirement is "one day" rather than "24 hours." For example, for a flight leaving Sunday at 3 p.m., the test needs to be taken anytime on Saturday or anytime on Sunday. This gives fliers more flexibility in scheduling their test for anytime the day before the flight.

Should we bring some at-home test kits with us?

Not a bad idea. The Food and Drug Administration has approved 13 home-based COVID tests, and families may want to bring some on the trip to use if anyone comes down with the sniffles or a cough, or to take just before getting to Grandma's. They may be hard to find in stores or limited to one or two per customer, so don't leave this errand to the last minute.

Family members may have varying risk tolerances, and at-home tests can help people relax and enjoy each other's company, Risse said, "because even though it is imperfect, it adds another layer of protection."

The CDC specifies which tests are allowed for entry into the United States. Self-tests for the virus are OK if there is an accompanying telehealth service providing "real-time supervision remotely through an audio and video connection." Your hotel may be able to point you to other testing options — like at medical clinics or pharmacies.

Is my child fully protected if they have had two vaccine doses?

Fully vaccinated, as defined by the CDC as two weeks after the second dose, is not the same as fully protected. Breakthrough cases occur but are generally mild. The advice from the CDC still stands: Children 5 and older should get the vaccine to protect them and those around them from getting COVID-19.

Should we hunker down between when we get our tests and when we travel?

It couldn't hurt, especially if you are traveling to see older or immune-compromised relatives, no matter their vaccination status.

Should we still go?

Every family needs to make its own decision to travel, based on the importance of their trip, how protected family members are and how much they trust fellow travelers to abide by the masking and social distancing rules that keep people safer. They also need to be aware of the levels of cases at their destination and the level of exposure their potential activities present, such as eating at a restaurant indoors or staying at a hotel instead of a private residence.

Vivek Garg, chief medical officer for Humana's senior-focused primary care business, encourages travel when CDC guidelines are followed.

"It's important for everyone's mental health, especially that of older adults, that we socialize with friends and family," Garg said.