Is Steam effective against Covid-19?

Felix Lin

You have been reading the rampant post about steam cleaning by autodetailers claiming it is effective against Covid-19. Before you send your vehicle to steam every surface, let’s find out some facts versus fiction.

If you didn’t stock up on bleach wipes and cleaning sprays before the big rush of panic buying, you’re probably frantically Googling “Does Steam Kill Covid?”. If you’re looking for other alternative cleaning solutions, one idea that’s been circulating online lately is steamers.

Some companies that make steamers claim that a blast with a steamer on soft surfaces such as upholstery can kill up to 99.9 percent of pathogens—which, for comparison, is the same track record claimed by many makers of bleach wipes and disinfectant sprays. Companies don’t go as far as to say that steamers can work on hard surfaces or take out SARS-CoV-2, the virus that causes COVID-19 (aka novel coronavirus), but this does leave us wondering about utilizing this common tool for virus protection backup.

Using a steamer seems like a great cleaning solution if you don’t have disinfectants handy or even if you prefer to clean your place without chemicals, but can steam really kill viruses?

Actually, under certain circumstances, yes. “We use steam under pressure to kill viruses in autoclaves,” says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. (An autoclave is a medical device that uses steam to sterilize equipment and other objects.) “Steam is how we sterilize medical equipment that we use in the laboratory,” says Dr. Schaffner.

However, that steam is used in a controlled setting under pressure (which allows the steam to reach higher temperatures), and it’s unclear if steam would be as effective against SARS-CoV-2 or any other virus on a surface like your vehicle dashboard. “I’m not sure whether the time-temperature relationships that you would use when you’re steaming a car interior would kill the virus,” says Dr. Schaffner. There’s no research on steam being used this way but, in theory, it might work, he adds.

As far as what the Centers for Disease Control and Prevention (CDC) has to say, the organization recommends that soft surfaces like carpets, rugs, and drapes be cleaned with basic soap and hot water. And for other frequently touched surfaces, it’s suggested that you disinfect these using a diluted bleach solution, an alcohol solution with at least 70 percent alcohol, and products that are on the Singapore Government’s disinfectant list.

If you’re interested in using a steamer to clean surfaces, Ruth Collins, Ph.D., an assistant professor of molecular medicine at Cornell University, recommends this hack to up your coronavirus protection: Lather up your surfaces with soap and hot water, and follow that with a good blast of steam to kill germs. While this coronavirus disinfecting method hasn’t been backed up by research, Collins points out that soap is known to dissolve the outer layer of SARS-CoV-2 and kill the virus. High temperatures can do the same. Together, she says, it should kill SARS-CoV-2, but again this isn’t foolproof and shouldn’t take the place of CDC-approved cleaning solutions.

Coronaviruses are enveloped viruses, meaning they have a protective membrane of fat, explains Collins. But that fat is “sensitive to detergent,” which is why the soap is a good partner, she says.

Steam may be effective on its own, but adding the soap is like extra insurance, says Collins. “If you put a thin film of soapy water down first and then come in with steam, you’ll have maximum penetration,” she says.

So, should you use steam to kill viruses? Experts are split: Some believe it works as an addition to other cleaners such as soap and water, while others don’t think steam can be as effective at killing viruses in real life as it is in a controlled lab setting. It’s important to reiterate that using steam as a way to kill viruses is not currently a disinfectant method approved.

That said, if you want to give steaming a try, there’s no harm in trying this. Just know that it may not be 100 percent effective.