If a person starts to feel symptoms typical of COVID-19, they may not be able to schedule a "gold standard" PCR test right away in New Jersey, and even after they do, it usually takes several days to learn test results.

By the time that person would find out they are COVID-positive, the clock will have been ticking or might have even expired on the window of contagion to others in their household.

Studies from the Centers for Disease Control & Prevention have indicated the probability of COVID spread within a home is about 50%, according to Howard Kipen, professor of environmental health at Rutgers University's School of Public Health, in Piscataway.

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That is because of how minuscule the coronavirus' particles can be — as small as 1/70th the diameter of a human hair — and how long they can hang around, Kipen said.

It's a change from popular pre-COVID thinking about airborne illnesses, most of which were historically shown to spread in relatively large particles within a close distance.

"There really is an appropriate concern for (SARS-CoV-2) particles that are floating in the air, and people who are caring for someone who's isolating need to be more careful," he said.

Kipen is the lead author of a study published in the journal Annals of the American Thoracic Society that attempts to shed some light on in-home COVID transmission within private, home settings.

'Measurable amounts of tiny particles' outside the isolation room

What Rutgers researchers found first, Kipen said, was not a surprise: that people with COVID symptoms or who had tested positive were not isolating as strictly as was necessary.

"But we also found, in both the so-called 'isolation room' and in another nearby room of the house, there were measurable amounts of tiny particles," he said.

The presence of SARS-CoV-2 particles in multiple areas of homes with a supposedly isolating resident emphasizes the need for better ventilation, according to Kipen.

That isn't always possible, either logistically or from a budgetary standpoint, especially in smaller dwellings with more occupants in low-income areas. But it is important to consider, simply because of the lag time from when contagion begins to the onset of symptoms to the return of a positive test.

"We know some of it's probably related to the kinds of jobs that people have, public-facing jobs, transit, et cetera, but some of it may well be at home, maybe even a large portion," Kipen said.

''Seem' is the operative word'

Cracking a window for an extended period isn't practical in current winter temperatures nor the dog days of summer, Kipen said, which means homes may need to go the route of businesses that have installed air cleaners.

"There are reports of gyms that have enhanced their ventilation, put air filters in their system, and they seem — 'seem' is the operative word — to not be hotbeds of contagion," he said.

Portable air cleaners have been the norm for homes in heavily polluted Asian cities for a while, according to Kipen, but he said studies on these devices' specific effectiveness against COVID have not yet been published in the U.S.

So until more is known, Kipen said the best defenses against contracting COVID in the home are high-quality masks, as much natural ventilation as possible ... and getting vaccinated.

Patrick Lavery is New Jersey 101.5's afternoon news anchor. Follow him on Twitter @plavery1015 or email patrick.lavery@townsquaremedia.com.

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