Science

How Risky Is It to Go Swimming This Summer?

Going to a pool isn’t fundamentally different from going anywhere else outdoors.

An empty hotel swimming pool in Palma de Mallorca, Spain
This pool is fine. Jaime Reina/AFP via Getty Images

Over the long weekend, people crowded into a pool in Missouri. Drinking in close proximity unmasked seems like an obviously bad idea. But it would be really nice to go swimming, now, soon, or at least sometime this summer. Is swimming, particularly in pools, another thing we’re going to have to give up until we are all vaccinated against the novel coronavirus? It is understandable to be wary of bathing in a vat of liquid that other people are also in or have been in recently. Let’s think through the risks.

Can I get the coronavirus at the pool?

Yes, but mostly because a pool is a place where you might be near a lot of other people, sharing bathrooms, using communal lounge chairs. As far as the pool itself goes, the water can be a good place to bump into someone unwittingly, especially if you are in a pool situation that involves cocktails or children. Mask-kinis aside (I refuse to say “trikini”), you also can’t wear a mask, get it wet, and then expect it to work or for you to be able to breathe. But the Centers for Disease Control and Prevention recommendations for safety at “aquatic venues” are pretty much the same as the safety recommendations that make sense for any open-air venues: There should be plenty of soap and room to social distance, and shared surfaces should be cleaned thoroughly between uses. Whether these things can happen realistically depends a bit on the design of the pool, and a lot on how many people are using the pool. But going to a pool isn’t fundamentally different from going anywhere else outdoors. It’s a small park, with water.

OK, but what about the water part? Can the coronavirus hang out in the pool water?

Highly unlikely! The CDC notes, “There is no evidence that COVID-19 can spread to people through the water used in pools, hot tubs, or water playgrounds.” A review paper published in the journal Water Research looked at what we know about coronaviruses in general (remember, the new one is part of a larger family including SARS) and notes that they’re unstable in chlorine. On top of that, the authors wrote that among coronaviruses “waterborne transmission has never been demonstrated in humans.”

So lakes and ocean are fine too?

Probably. Though they don’t have chlorine, as a few experts explained to the Los Angeles Times, it’s unlikely that you’d catch the coronavirus from an ocean or large lake namely because any virus that did potentially survive while floating around would be very, very diluted in all that water. “I can tell you that it would never cross my mind to get COVID-19 from a swimming pool or the ocean,” immunologist Paula Cannon told reporter Christopher Reynolds. Bizarre scenarios could still happen, of course. An atmospheric researcher told the LA Times last month in a different article that she was worried about the ocean aerosolizing particles of the coronavirus, sort of sneezing them back into the air. But that’s speculation at this point.

In the sense of crowds, depending on what you have available near you, beaches and lakes might be better than pools. A beach with a lot of people can offer a lot more space than a pool with a lot of people, where you might be maneuvering through one entryway and around small, slippery areas of concrete and tile between chairs and the water.

Back up—it sounds like you’re saying the water is fine. But people do get sick swimming sometimes.

Right. There are a few ways that viruses make their way into water: mucus, vomit, or, namely, “accidental release of fecal matter,” as researchers at the Italian National Institute of Health wrote in a review paper on viral swimming pool diseases last year. There’s a reason most illnesses that spread through water, like those caused by Giardia and norovirus, involve diarrhea. Now, diarrhea is a somewhat common symptom of COVID, and it’s something of an open question whether the coronavirus could spread via poop. The CDC currently notes that there haven’t been any confirmed cases of fecal transmission, but this is probably the one main thing to keep an eye on in relation to swimming.

Just tell me if it’s OK to go swimming or not.

I mean, the actual part where you’re in the water, even water that other people have been in recently, is, based on the information we have right now, fine. It’s also true that new information on how the novel coronavirus behaves and what the risk level is could emerge; we’ve seen that happen time and time again since January. It’s also true that the safest thing to do right now is to stay in your home or to travel only to places where there aren’t other people you could be bumping into, water or no.

Right. And beaches and all that can draw a lot of crowds. Why not just err on the side of caution here and keep them closed?

Being super cautious about water recreation is definitely a personal choice that could make sense right now. It’s one that might make a lot more sense if you have a backyard or space for a homespun water recreation setup. But the consequences of banning swimming in public places aren’t zero; last week a 24-year-old drowned in New York where there are no lifeguards on duty. And, as far as exercise goes, swimming somewhere outdoors and uncrowded is, based on what we know now, much safer than going to an indoor gym, which public health experts do not think is a good idea because you’re in a confined space and sharing equipment. On a public health level, it’s probably not realistic to expect everyone to be on board with an approach that restricts going to any nonessential, fun place where you might, sometimes, get within 6 feet of another human being, or where you have to use a public restroom occasionally, or where there’s some little possibility of ingesting matter that has come from someone else’s body. In other words: Everything has some level of risk. Swimming does not have zero risk, but the risk is not that high. If you can tolerate that, dive in.