Successful travel starts with being prepared for the unexpected. Coronavirus disease 2019, known as COVID-19, is now a part of standard travel planning.

As you choose a destination, travel group or event, add COVID-19 to the list of things to research. When packing for yourself or anyone you're caring for on the trip, consider COVID-19 prevention and testing.

No one wants to plan for the worst. But having a plan in case you catch the COVID-19 virus while traveling can save time if you need medical care.

To start, it can help to ask these basic questions as you make plans.

Staying up to date on your COVID-19 vaccine helps prevent serious illness, the need for hospital care and death due to COVID-19.

If you need a vaccine, plan to get it at least a few weeks before you travel. Protection from the vaccine isn't immediate.

Many people with COVID-19 have no symptoms or mild illness. But for older adults and people of any age with certain medical conditions, COVID-19 can lead to the need for care in the hospital or death.

If you or those around you are at high risk of serious COVID-19 illness, take extra safety measures during or after travel.

Ask a healthcare professional if there are any specific actions you should take.

The country you travel to may not need to know your COVID-19 status. But you might need the information for other reasons.

Events, venues or tour groups might require proof that you are COVID-19 negative or are up to date on a COVID-19 vaccine. Check before you go so you have all the paperwork you need.

No one wants to get sick while traveling. But in case you do, it helps to know where you can get medical care and whether you'll be able to stay apart from others while you have symptoms.

Put together a COVID-19 kit with rapid home tests, masks, a thermometer, disinfectant wipes and hand sanitizer that contains at least 60% alcohol.

Before you leave, gather health information from your healthcare professional. Make sure it gives the details on any health conditions you're managing and medicine you take.

The virus that causes COVID-19 spreads mainly from person to person. When the virus is spreading, spending time indoors with a crowd of people raises your risk of catching it. The risk is higher if the indoor space has poor airflow.

The coronavirus is carried by a person's breath.

The virus spreads when a person with COVID-19 breathes, coughs, sneezes, sings or talks. The droplets or particles the infected person breathes out could possibly be breathed in by other people if they are close together or in areas with low airflow.

The virus carried by a person's breath can land directly on the face of a nearby person, after a sneeze or cough, for example. And people may touch a surface that has respiratory droplets and then touch their faces with hands that have the coronavirus on them.

While you travel, one way to lower your risk of COVID-19 is to clean your hands often.

Wash your hands after using the bathroom, before making food or eating, and after coughing, sneezing or blowing your nose. If you touch something that others regularly touch, such as an elevator button or a handrail, make sure to clean your hands afterward.

Also, try to avoid touching your eyes, nose or mouth.

Wearing a face mask is another way to lower your risk of COVID-19.

Travel brings people together from areas where viruses may be spreading at higher levels. Masks can help slow the spread of respiratory viruses in general, including the COVID-19 virus.

Masks help the most in places with low airflow and where you are in close contact with other people. Also, masks can help if viruses are spreading at high levels in the places you travel to or through.

Masking is especially important if you or a companion have a high risk of serious COVID-19 illness. Choose the most protective mask that fits well and is comfortable.

As the virus that causes COVID-19 changes, COVID-19 vaccines are updated, so stay up to date with the recommended shots.

Check with health agencies in the area to see where the COVID-19 virus is spreading. Information about the spread of the virus may include the number of people in the hospital with COVID-19 or the number of people who test positive for the disease.

Choose outdoor activities and keep some distance between yourself and others. Poor airflow plus lots of people crowded together equals a higher chance you'll come in contact with the virus that causes COVID-19.

If you can, try to avoid spending time with people who have COVID-19 symptoms or who are sick.

There will likely be times during travel when you don't have a choice about how close you are to others. Here are some tips for air travel, public transportation and lodging.

The risk of catching the virus that causes COVID-19 from air travel is thought to be low.

Air in the plane's cabin changes over quickly during the flight, being replaced every few minutes in some planes. Airplane air also is often filtered. So germs, including viruses, are trapped before they spread.

The air flowing down from vents above the seats in each row may help keep germs from spreading. Seats also may act as a barrier to germ spread on a plane, unless the person who is ill is sitting close to you.

You can help lower your risk by spreading out to keep distance between you and others when you can and cleaning your hands regularly.

Wearing a mask in crowded areas, such as security lines and bathrooms, can help protect you from COVID-19 and other respiratory illnesses.

Trains and buses may have good airflow and air filtering. But check before you travel so you know what to expect. When a vehicle is crowded, wear a face mask and take other steps, such as cleaning your hands.

Taxis and private cars used for ride-sharing may not have air filtering. But in most cases, rolling down a window could be an option to improve airflow.

Rental car companies may post their cleaning policies on the internet, or you can ask directly when you book the vehicle.

Cleaning protocols at hotels, vacation rentals and other lodging have largely returned to the way they were before the COVID-19 pandemic. If you have questions about how hosts or businesses protect guests, contact them directly. In public areas of hotels, take steps to lower your risk of catching the virus that causes COVID-19.

Despite your planning, an illness may delay or cancel your trip. Stay home if you or anyone you're traveling with has:

• Symptoms of COVID-19, such as fever or new loss of taste or smell.
• Taken a COVID-19 test and is waiting for results.
• Been diagnosed with COVID-19.

Keep watch for serious symptoms of COVID-19, such as trouble breathing or chest pain. If you or a person you're taking care of has symptoms that worry you, get help.

Once the fever is gone and symptoms are getting better, you may choose to travel. But for about five days after feeling better, you could still give others the virus that causes COVID-19. Take extra actions to protect the people around you.

• Wear a mask.
• Keep your distance from others, especially when indoors.
• Clean your hands regularly.
• Keep the air flowing by turning on fans or opening windows when you can.

If you start to feel worse or your fever comes back, avoid being around others again until you feel better.

With COVID-19 vaccinations, testing and treatment, events and travel are back to typical levels in many places. But as waves of COVID-19 outbreaks happen, it's important to stay flexible with your plans. Knowing whether the COVID-19 virus is spreading in your area or in places where you're traveling can help you make decisions about whether to go and what to put on your agenda.