At a Glance
- Research indicates that SARS-CoV-2, the virus responsible for COVID-19, can remain detectable in the air for up to three hours and on plastic and stainless steel surfaces for as long as two to three days.
- These findings underscore the critical role of regular hand washing and disinfection of frequently touched surfaces as key protective measures against infection.
Novel Coronavirus SARS-CoV-2
It’s a common concern: how long do viruses, particularly the novel coronavirus, linger on everyday surfaces outside the human body? According to the Centers for Disease Control and Prevention (CDC), contracting SARS-CoV-2, the virus causing the current global pandemic, is possible by touching a contaminated surface or object and then touching your face. While person-to-person transmission via respiratory droplets from coughs or sneezes is considered the primary route of spread, understanding surface persistence remains crucial for public health.
To shed light on this, scientists at the National Institutes of Health (NIH), led by Dr. Vincent Munster from the National Institute of Allergy and Infectious Diseases (NIAID), conducted a detailed study. Their research mimicked the ways in which viruses spread from an infected individual to surfaces in homes or healthcare facilities – through coughing or direct contact. The team then meticulously examined how long the virus remained infectious on these various materials.
The study, published in the esteemed New England Journal of Medicine on March 17, 2020, drew comparisons with SARS-CoV-1, the virus responsible for the Severe Acute Respiratory Syndrome (SARS) outbreak in 2002-2004. This comparative approach aimed to provide context and understand the unique characteristics of SARS-CoV-2.
Researchers tested the virus’s stability on a range of common materials: plastic, stainless steel, copper, and cardboard. They also employed a specialized rotating drum to aerosolize the virus, creating a mist of tiny droplets to simulate airborne suspension and assess its longevity in the air.
The results revealed that SARS-CoV-2 could remain viable on plastic and stainless steel for a notable duration – two to three days under the experimental conditions. On cardboard, the infectious period was shorter, up to 24 hours, and on copper, it was the shortest at around four hours. Importantly, the virus was found to be detectable in aerosols for up to three hours. It’s essential to note that these durations can fluctuate in real-world settings, influenced by factors such as temperature, humidity, ventilation, and the initial viral load deposited.
These findings suggest that surface transmission of SARS-CoV-2 is indeed plausible, alongside airborne transmission. While the study demonstrated the virus’s ability to infect cells in a lab environment, the precise amount of virus needed to cause infection in humans requires further investigation.
Interestingly, the stability of SARS-CoV-2 appears to be similar to that of SARS-CoV-1. This raises a critical question: why has COVID-19 resulted in a far larger global outbreak compared to the SARS epidemic, which infected approximately 8,000 people across 26 countries and was successfully contained through isolation and contact tracing?
Dr. James Lloyd-Smith, a co-author from the University of California, Los Angeles, points out, “These findings show that SARS-CoV-2 is actually quite similar to SARS-CoV-1 in terms of stability in the environment. This means we can learn from our experiences with SARS in 2002-2004 to gain insights into infection control, especially in healthcare settings. On the other hand, it indicates that the major differences in the epidemiology of these viruses probably arise from other factors—especially the ability of SARS-CoV-2 to be transmitted by people not exhibiting clear symptoms.” This highlights the role of asymptomatic transmission as a key differentiator in the spread of COVID-19.
Dr. Susan Gerber, another co-author from the Centers for Disease Control and Prevention, emphasizes the broader implications: “These results will inform future epidemiologic investigations that will be necessary to understand spread of this virus person to person.”
Ultimately, this research reinforces the critical importance of simple yet effective hygiene practices. Frequent hand washing and disinfecting frequently touched surfaces and objects using household cleaning sprays or wipes are vital steps in minimizing the risk of transmission. Avoiding touching your eyes, nose, and mouth, practicing social distancing by avoiding close contact with sick individuals, and staying home when you are unwell remain crucial recommendations for preventing the spread of coronavirus and protecting public health, not just in specific months like May, but throughout the year.
