Summer vacation can seem suspect at a time when the coronavirus is circulating and as many as 40% of transmission may come from those bearing no symptoms. To help with trip planning, we checked in with two infectious disease specialists: Dr. Michael Osterholm of the University of Minnesota and Dr. Frank Rhame with Allina Health.

Both say the key to staying virus-free, vacation or not, is to minimize contact and stay 6 feet from those outside your family.

"Distancing is the No. 1 means of reducing risk," Osterholm said.

Rhame said that knowing how the virus is transmitted should guide people's choices about all kinds of activities. Touch is the least worrisome, though we need to wash hands after encounters with high-touch surfaces like door handles, he said. The virus travels in small droplets, and even gentle speakers "spew out an order of 1,000 droplets per second." The droplets evaporate "pretty quickly," but can hover around, especially where there is little airflow. The big droplets, which also can contain virus, fall to the earth, usually within 6 feet.

Two key factors play a role in infection: the dose that is in the air and how long a person breathes it in, Osterholm said.

"If people don't get closer than 6 feet and have the decency to wear a mask, it's probably OK," said Rhame, who noted that mask wearing is more for the safety of nearby people than the person wearing the mask.

In the end, safety is largely about with whom you vacation.

Osterholm said. "If you are with your family unit, and you limit exposure to the outside world, that's the key."

Is a lodge room less safe than a cabin? Either is fine, provided air is flowing. Rhame said that in a cabin or a lodge room, "I'd be opening windows when I arrive." He frowned on elevators, where fine droplets from a passenger who got off minutes earlier could be lurking.

Can I go swimming in a pool or to the beach? Swimming is a problem because you can't use a mask. In the splashing fun of a pool, maintaining distance could be a challenge. Beaches could be easier.

Is camping safe? "If you are camping with a group or at a centralized recreation area with 30 other people, then your chance [of getting the virus] is much higher than if you are just out and about in a campground with your family," Osterholm said.

If we all take a coronavirus test and are negative, can I travel with friends? "Testing is not helpful" in such a situation, Osterholm said. People who have a small but building amount of virus may test negative and only several days later — say, when you're all in a rental home together — start shedding the virus. Also, in Minnesota the tests are given almost exclusively to people who are ill or who have attended recent demonstrations.

Drive or fly? Here, opinions diverge. "Driving is by far the best," said Osterholm, who advises people to make quick rest stops, avoid lines and be careful pumping gas. Rhame notes that half of the air in planes comes from the outside and the rest passes through filters. "Airplanes are actually pretty safe once you get on them. It's getting to them that you have to worry about." Nearby passengers can also be cause for concern. But there is no navigating rest stops, hotels and meals.

What to bring on vacation this year

Your vacation will look a little different this summer — and your suitcase will, too. Remember to bring these things, for the drive and the destination:

• Masks for everyone.

• Laundry detergent for cleaning the masks.

• Hand sanitizer with at least 60% alcohol.

• Tissues for encounters with high-touch surfaces like doors.

• Bleach-based or hydrogen peroxide cleaners to rid surfaces of virus.

• Consider purchasing an annual state park permit before you head out. Many visitor centers and ranger stations are closed.

• A cooler with snacks for the drive and many of the foods you'll need at your destination.

• A thermometer, just in case.

Kerri Westenberg