Annie Hsia asked for evidence behind using steam to sterilize clothes contaminated with coronavirus. What a fantastic question! Steam might sound safer than harsh disinfecting products, but is it effective at disinfecting? Let’s examine the evidence behind this myth.
Steam to disinfect surfaces from coronavirus to reduce COVID-19 infection
Killing coronavirus with steam has been a popular home remedy myth for months, and perhaps not without reason. SARS-CoV-2 is a member of the coronavirus family, and other coronaviruses are known to be easily destroyed at higher temperatures (called thermolabile). This is good news for us, because 60 degrees Celsius is the range at which the virus begins to die, and this is commonly reached when cooking food. This is the rationale behind why cooked food is highly unlikely to transmit virus to us (also because swallowed food is unlikely to introduce virus into our respiratory tract).
People around the world have taken this limited knowledge, however, and tried to extrapolate it to unproven treatments. It makes sense that boiling water would release steam above 60C and should destroy the virus. However, there is absolutely no evidence that inhaling steam (such as from boiling water) will actually destroy viruses already in our bodies, such as in our lungs. For all we know, the virus may be safely protected inside our cells at the time of inhaling steam, and remain shielded from the elevated temperatures that would ordinarily kill a naked virus in the air or on an inanimate surface. Furthermore, steam from a humidifier that is not heated would not even carry this theoretical benefit.
So, it is safe to say that inhaling steam from boiling water increases your chance of hurting yourself but does not provide an evidence-based strategy for reducing your chance of infection or decreasing symptom duration.
More importantly, disinfecting or cleaning chemicals should never be heated or inhaled, as this may cause serious injury to our lungs.
Let’s leave this home remedy myth behind.
Steam therapy to “clean” lungs and prevent COVID-19 or reduce symptoms?
The next question is whether we can use steam to kill a virus outside of our bodies. This is a more reasonable question, as we know that high temperatures can destroy virus on inanimate objects. In fact, one of the methods of sterilizing surgical equipment in hospitals involves using high temperatures. However, there is a significant difference: when using steam to disinfect hospital equipment, there are very specific parameters for the disinfection process, including temperature, pressure, duration, object type, etc. These parameters have been extensively studied to ensure that the particular object being sterilized will truly be clean and free of any viruses or bacteria.
Unfortunately, while convenient, using steamers at home, even if at high temperatures, likely will not provide consistent conditions that can be repeated with precision. Furthermore, the specific temperature, duration, etc. may vary based on the item to be sterilized with steam. Therefore, I would not recommend anyone to use a steamer to sterilize objects at home, particularly if we have effective alternatives for home disinfecting and cleaning against SARS-CoV-2.
We know that the detergents in soap easily destroy coronavirus’s envelope, meaning that laundering close can destroy the virus effectively. We also have several disinfectants that can be used to sterilize hard surfaces. Please see my previous post for a strategy to find the safest disinfecting for your home.
Take home: please do not use steam therapy to disinfect surfaces around your house, clothes, or to prevent or treat infection in yourself. This home remedy myth in fact poses harm to you if objects are not cleaned properly. Warm temperatures will kill the virus in your food, making it generally unlikely that you will transmit virus to yourself through swallowed food (but utensils are a dangerous transmission vector, so be sure to wash your utensils and not share them with anyone who is sick!).
Please keep asking your questions! I’d love to hear from you so we can answer more popular questions and spread accurate information!