Kids need to go outside. No amount of severe acute respiratory syndrome-causing virus will change that fact. If you have a backyard, a coronavirus quarantine is an excellent time for an open-door policy. If you don’t, you might be tempted to head to the playground. But is it safe? One thing is for certain — if it’s crowded, skip it. It’s just as risky as a playdate and right now everyone social isolation is your best bet to avoid the virus. If the playground is (relatively) empty on the other hand, well, there’s good news and bad news. First the bad: There might be COVID-19 lying in wait on the swings or slides. The good? As it gets warmer, there’s a good chance the heat will kill it dead. Either way, you’re going to have to wait.
The science of COVID-19 is still quite preliminary, and we don’t actually know how readily contaminated surfaces cause infection. Most cases of coronavirus come from direct person-to-person contact, according to the CDC. While the agency acknowledges that coming into contact with contaminated surfaces most likely contributes to the outbreak, this type of spread hasn’t yet been documented. To playground or not to playground? Here’s what the science says so far.
Plastic: Skip the Swings and Tunnels
Of all the surfaces on the playground, plastic slides, climbing walls, and tunnels are most likely to harbor the novel coronavirus. A team of researchers from the National Institutes of Health, Princeton University, and the University of California Los Angeles dropped small amounts of COVID-19 on various surfaces to see how long it would survive. Their research, which was published on the preprint site MedRxiv and has yet to be peer-reviewed, found that the virus lasted longer on plastic than on any other material they tested — it took 16 hours for half of the COVID-19 to die, and the sample didn’t completely disappear from the surface for 2-3 days.
Even outside of a pandemic, plastic and other hard surfaces are notoriously germy compared to more porous surfaces, like wood, according to the Mayo Clinic. Previous studies have found that other coronaviruses, like the one that caused the SARS epidemic in 2003, can survive on plastic for anywhere from 6-9 days.
Metal: Slide with caution.
From monkey bars to chains on swing sets, metal equipment likely isn’t much better than plastic. In the same study, researchers found that COVID-19 lasted about as long on stainless steel as on plastic.
Certain kinds of metal might be more hospitable to the virus than others — COVID-19 only lasted for four hours on copper, which is toxic to microorganisms. Another study, published in The Journal of Hospital Infection, found that the common cold, another coronavirus, lasted just hours on aluminum.
Wood: The better playground option.
From toadstool steps to playhouses, it’s unclear how coronavirus fairs on wood. No research to date has measured how long it survives on the surface. When it comes to bacteria, wood is generally more hygienic — wood’s tendency to absorb moisture dries microbes out. However, a review of previous research on other coronaviruses found that SARS-CoV-1, the virus responsible for the SARS epidemic, lasted for up to four days on wooden surfaces.
Sand: Beware The Box
It’s time to beware the sandbox, once and for all. Scientists haven’t looked into how long COVID-19 can last in a sandbox, but plenty of research suggests that sandboxes are cesspools of germs and parasites, ranging from toxoplasmosis from cat feces to diarrhea-causing C. Difficile. In 2008, NSF International found that out of 26 different surfaces sampled, sandboxes harbored more germs than library books, toys at doctors’ offices, or even the door handles of public restrooms. There’s no evidence that coronavirus is necessarily part of that microbial grab-bag — but given this literal litterbox usually ends up in your kid’s mouth, does it matter?
The Great (Disinfectant) Outdoors
It’s important to keep in mind that the novel coronavirus likely lasts longer on surfaces under controlled laboratory conditions. This is the message Dr. Oxiris Barbot, New York City’s health commissioner, gave to listeners at a press conference last week. Outside, where humidity and heat and UV rays tend to kill off viruses, coronavirus could linger for a fraction of that time.
Coronavirus spreads through the droplets of mucus and saliva that go flying when we sneeze or cough. These don’t tend to get too far. Six feet is the commonly espoused number, according to the CDC. But whether COVID-19 is airborne (able to linger in the air) is more uncertain.
Whether a disease is considered airborne or not is based largely on the size of the droplets that carry the infection — are they smaller or larger in size than five microns? It’s a fine line, and the recent MedRxiv study suggests that COVID-19 might also travel in tinier droplets called aerosols, which linger in the air for longer periods of time. After spraying the virus into a rotating drum, scientists found that the disease hung in the air for at least three hours.
If COVID-19 does travel through aerosols, distance is essential, as is a well-ventilated area. Empty playgrounds then? Should be fine. But even a small crowd might be very risky with this virus.
Sunlight kills viruses because of ultraviolet radiation (UV), which are deadly to them. Scientists from the U.S. Food and Drug Administration exposed small amounts of SARS-CoV-1 to ultraviolet radiation.They found that 6 minutes of exposure was enough to kill all but a tiny fraction of their samples. However, they used UVC radiation, a more intense form of ultraviolet light that doesn’t ever reach the earth. The UV light that reaches ground-level is of the UVB and UVA variety, which are less damaging to viruses. Research hasn’t documented the effects of these types of radiation on coronaviruses.
Also, heat doesn’t help the virus. Some preliminary data suggests that coronavirus has a “sweet spot” between 41 and 52 degrees, but it hasn’t been thoroughly tested. We also know that other coronaviruses, like SARS, can be inactivated at temperatures of 86 degrees Fahrenheit and higher. However, the CDC is cautioning people not to assume that the virus will go away when it warms up — we don’t know that. Some experts think it will behave differently from the flu, and continue to spread normally during the spring and summer.