SARS-CoV-2, the virus causing COVID-19, can be shed onto household surfaces through respiratory droplets. Understanding how long it remains infectious on these surfaces is important for maintaining a healthy living environment and reducing potential exposure.
Factors Affecting Virus Survival
The viability of SARS-CoV-2 on surfaces is influenced by several environmental and material factors. Surface type plays a significant role, with non-porous materials like plastic and stainless steel allowing the virus to survive longer than porous surfaces such as fabrics or cardboard. Lower temperatures tend to prolong the virus’s infectiousness, while higher temperatures lead to more rapid inactivation. Humidity also affects viral stability; moderate levels might support longer survival, whereas very high or very low humidity can be less favorable. Exposure to sunlight’s ultraviolet (UV) radiation can quickly inactivate SARS-CoV-2.
Survival Times on Common Surfaces
SARS-CoV-2 can persist on various common household surfaces for different durations. On hard, non-porous surfaces like plastic and stainless steel, the virus can remain viable for 48 to 72 hours, with some studies suggesting up to 28 days under cooler, controlled conditions. Cardboard surfaces generally show a shorter survival time, typically remaining infectious for up to 24 hours.
Copper rapidly inactivates the virus, limiting its survival to approximately 4 hours. Glass surfaces can support virus viability for an extended period, potentially up to 28 days at room temperature. On porous materials such as fabrics, the virus tends to be less stable, though it can still last about two days on some textiles. These figures often come from laboratory settings, and real-world conditions may lead to different survival times.
Reducing Virus Presence in Your Home
Effective cleaning and disinfection practices minimize SARS-CoV-2 presence on surfaces. Cleaning with soap and water removes germs and dirt, while disinfection uses chemicals to kill germs. For disinfection, products containing at least 60-70% ethanol, such as alcohol-based disinfectants, are effective. Household bleach, properly diluted (e.g., 1:200 ratio), is also effective.
Simple dishwashing detergents can inactivate the virus when diluted appropriately (e.g., 1:100 ratio), but vinegar is largely ineffective. When cleaning, first wash dirty surfaces with soap, then apply a disinfectant, allowing it to remain wet as per product instructions. Good ventilation, by opening windows and using fans, also helps dilute airborne virus particles that can settle on surfaces.
Understanding Surface Transmission
While SARS-CoV-2 can survive on surfaces, the primary way people become infected is through respiratory droplets and aerosols in the air. Transmission through contaminated surfaces, known as fomite transmission, is generally considered a lower risk compared to airborne spread. The amount of infectious particles on a surface tends to decrease significantly over time.
This natural degradation, combined with routine cleaning, lowers the potential for transmission. Regular cleaning with soap or detergent is often sufficient to reduce this risk. Disinfection becomes more important when a person with confirmed COVID-19 has recently been present.