The SARS-CoV-2 virus, which causes COVID-19, can be inactivated on surfaces using heat. Understanding how heat impacts this virus is important for effective disinfection strategies. Viral inactivation refers to the process of rendering a virus non-infectious.
How Heat Affects the Virus
SARS-CoV-2 consists of genetic material encased within a protein shell and a lipid envelope. Heat primarily inactivates viruses by denaturing, or breaking down, these essential proteins and damaging their genetic material. When proteins lose their proper structure, they can no longer perform their functions, rendering the virus unable to attach to host cells or replicate.
This process renders the virus non-infectious, rather than “killing” it, as viruses are not considered living organisms. Heat effectively compromises the viral structure, making it incapable of causing infection. The lipid envelope and spike proteins, crucial for the virus to enter host cells, are particularly susceptible to heat.
Temperature and Time for Inactivation
The effectiveness of heat in inactivating SARS-CoV-2 depends on both the temperature applied and the duration of exposure. Higher temperatures require shorter exposure times for significant viral inactivation. For instance, studies indicate that SARS-CoV-2 can be largely inactivated at 56°C within 30 minutes. Increasing to 60°C can achieve a substantial reduction in 30 minutes, while 65°C may require 15 minutes.
At higher temperatures, the inactivation time decreases further. Research suggests that 70°C can inactivate the virus in as little as 5 minutes. For rapid inactivation, temperatures of 80°C for 1 minute or even 92°C for 15 minutes have been shown to be effective in laboratory settings. These figures are based on laboratory studies, and real-world conditions can vary.
Using Heat for Disinfection
Heat is a practical tool for disinfecting surfaces and items. For laundry, washing clothes or linens at high temperatures (60°C to 90°C) with laundry soap or detergent helps inactivate the virus. This method is commonly recommended for contaminated items.
Steam cleaning is another effective application of heat for disinfection, particularly for surfaces like floors and upholstery. Steam cleaners generate high temperatures, which can break down viral structures. Ensuring adequate contact time with the surface is important for optimal effectiveness.
The principle of heat inactivation is also applied in industrial processes like pasteurization, which uses controlled heat to eliminate pathogens from food products. This established method demonstrates the scientific validity of heat as a disinfectant. While not for household use, it illustrates how heat reliably inactivates viruses by denaturing their structures.
Key Safety Considerations
Despite the effectiveness of heat in inactivating SARS-CoV-2 on surfaces, important safety precautions are crucial. Heat is not a treatment for COVID-19 infection within the human body. Consuming hot liquids or attempting to raise body temperature internally to “kill” the virus is ineffective and potentially dangerous, carrying risks such as burns to internal tissues.
Using excessively high temperatures for disinfection can also damage certain materials, fabrics, or electronics. Always check manufacturer guidelines for items before applying heat. Hot water and steam pose a significant risk of burns and scalds to individuals. Water temperatures as low as 48°C can cause scalding, and higher temperatures can result in severe burns in seconds.
When using steam cleaners or hot water, proper ventilation is necessary to prevent steam buildup in enclosed spaces. Wearing appropriate personal protective equipment, such as heat-resistant gloves and safety goggles, is advised to prevent injuries. Heat disinfection should complement other recommended public health practices, including regular handwashing, mask-wearing, and vaccination, rather than replacing them.