The long and short of social distancing during the COVID-19 pandemic is that when it comes to interacting with people outside your household, you should be no less than 6 feet away, whether inside or outside.

This has become increasingly important, as the number of confirmed cases rises; on Saturday, a 43-year-old Norwich man was confirmed to have the disease, the first case in the Uncas Health District and second in New London County.

The Centers for Disease Control and Prevention defines social distancing as “remaining out of congregate settings, avoiding mass gatherings, and maintaining distance (approximately 6 feet or 2 meters) from others when possible.”

This has people asking a lot of questions about what they can and can’t do.

For example, someone might be calling Steve Mansfield, director of health for the New London-based Ledge Light Health District, to ask if they can play tennis with a partner.

“My answer is, ‘Well, you tell me. Are you going to come in close contact with that person when you ordinarily wouldn’t?’” Mansfield said. He added, “If you’re confident that your social distancing will keep you at least 6 feet apart and you’re not going to be subject to droplet contamination, you’re not going to increase your risk.”

A report published in the New England Journal of Medicine on Tuesday said the coronavirus can remain viable in air for up to three hours, though droplets mostly fall more quickly.

Droplets can be passed on through a sneeze or breathing vapor, Mansfield said. An avid biker, he frequently went on road rides with friends in pre-pandemic times. But now he told them he won’t go on rides and recommends they don’t either, “because there’s a risk that I’m going to come in contact with other people’s exhalations.”

Marc Zimmer, a Connecticut College chemistry professor who teaches a course called Diseases Without Borders, said in a typical sneeze, there are 40,000 little droplets that are ejected at 200 miles an hour.

Yes, you can still go outside

Mansfield said outside and ventilated areas are generally safer because the virus can dissipate, “but it’s not safe, it’s just safer.”

He said people have to realize their “day-to-day activities are going to be changed dramatically” but said they could go to local spots like Bluff Point State Park and Haley Farm, so long as they remain at least 6 feet apart.

Dr. William Horgan, regional director of quality and safety for Hartford HealthCare, said droplets fall out of the air at a range of 3 to 4 feet, hence why 6 feet is considered a safe distance.

In California, Gov. Gavin Newsom issued a stay-at-home order Thursday but a FAQ from the state said, “So long as you are maintaining a safe social distance of six feet from people who aren’t part of your household, it is ok to go outside for exercise, a walk or fresh air.”

While indoor facilities and campgrounds are closed in California state parks, trails are still open, and state officials noted that spending time outside “can lead to a number of overall health and wellness benefits like lessening anxiety, boosting creativity and getting your vitamin D.”

A stay-at-home order from Los Angeles Mayor Eric Garcetti, also issued Thursday, specifically said that people could leave their home to engage in outdoor activity and recreation, “including, without limitation, walking, hiking, running, cycling; use of scooters, roller skates, skateboards, or other personal mobility devices; or travel in a vehicle with household members to a location where it is possible to walk, hike, run or ride a bike, or operate personal mobility devices, while maintaining social distancing practices.”

But Los Angeles closed outdoor and indoor playgrounds.

If you’re wondering whether to engage in a certain outdoor activity, ask yourself whether you’ll be touching a surface with your hands that other people have touched or will touch. If so, the answer is probably don't do it.

The New England Journal of Medicine study found that the coronavirus remained viable on stainless steel and plastic for up to 72 hours, cardboard for 24, and copper for 4.

Lessons from the 1918 influenza pandemic

Doctors typically urge people not to make comparisons between the flu and COVID-19, because of significant differences in the average number of cases resulting from one case, the length of time it takes to transmit the virus, and mortality rates.

But one area that is instructive is measures taken during previous pandemics, primarily the 1918 influenza pandemic. This killed about 50 million people worldwide, at a time when the global population was much smaller.

Horgan, of Hartford HealthCare, said Philadelphia ignored warnings and held a big parade, and “two days later the number of severely ill jumped through the roof.” Between Sept. 20 and Nov. 8, 1918, the city recorded 12,687 deaths from the flu and related pneumonia, The Philadelphia Inquirer reported.

But in St. Louis, “authorities moved rapidly to introduce a broad series of measures designed to promote social distancing” and implemented them two days after the first cases were reported among civilians, according to a 2007 article published in the Proceedings of the National Academy of Sciences. St. Louis experienced a death rate of 31 per 100,000, while the rate was 257 per 100,000 in Philadelphia.

A different PNAS article from 2007 cited St. Louis, San Francisco, Milwaukee and Kansas City as the cities with the most effective interventions, reducing transmission rates by up to 30%-50%.

Interventions in the U.S. in 1918 included closing schools and churches, banning mass gatherings, and case isolation. The issue is that if interventions were lifted too early, there would be a second wave of cases.

The study said control measures may have been “too effective” in cities that saw two peaks that autumn, because there were still many susceptible people when controls were lifted.

While the authors said it appeared no U.S. cities found the “optimal middle ground,” the ones that got closest to the maximum possible reduction in death rates were those “that implemented both early and effective interventions throughout the first peak and then were able to reintroduce these when transmission again increased.”

Findings on the efficacy of social distancing in 1918 hold true outside the U.S.

A 2007 study in the Journal of the Royal Society Interface estimated that 260 lives per 100,000 were saved in Sydney, Australia, because of interventions.

But the beginning of a second wave of cases coincided with the lifting of infection control measures, the study said. Because incidences remained low compared to epidemics elsewhere in the world, authorities thought the threat had passed and lifted most measures on March 1, 1919, but three weeks later, 20 people died one weekend and measures were re-imposed.

A 2017 study published in the Public Library of Science modeled the effects of social distancing on three flu waves in the United Kingdom. The authors found that the estimated infection attack rate is 40.8% without behavioral changes and 28.5% with behavioral changes.

e.moser@theday.com