[BenIndy editor: Note that aerosol-generating particles CAN be generated in normal coughing. See this 2015 NIH study. – R.S.]
As the world shifts toward a concept of social distancing as part of an attempt to protect against the novel coronavirus, new research is showing the virus that causes COVID-19 is quite stable on hard surfaces, and even in the air.
A study conducted by researchers from the National Institute of Allergy & Infectious Diseases (NIAID) reveals that the virus is stable for “hours to days in aerosols and on surfaces.” The results of the study were published in The New England Journal of Medicine. According to the study, in aerosol form, the droplets from a cough, SARS-CoV-2, the virus that causes COVID-19 disease, is stable for up to three hours. Depending on environmental factors, the droplets can remain suspended in air, during some or all of this time. On hard surfaces such as copper, the virus is stable for about four hours. On cardboard, the virus is stable for a full day and on plastic and stainless steel, the virus is stable for three days, the researchers discovered. These results suggest that people “acquire the virus through the air and after touching contaminated objects.”
Because of the concerns of the virus surviving in air for some time, the World Health Organization is considering adding “airborne precautions” for medical staff addressing the virus, CNBC reported. Dr. Maria Van Kerkhove, head of WHO’s emerging diseases and zoonosis unit, told reporters that the virus is transmitted through droplets from sneezing or coughing.
“When you do an aerosol-generating procedure like in a medical care facility, you have the possibility to what we call aerosolize these particles, which means they can stay in the air a little bit longer,” Van Kerkhove said, according to CNBC. “It’s very important that health-care workers take additional precautions when they’re working on patients and doing those procedures.”
The study wanted to mimic the ways that the virus can be transmitted from an infected person by coughing or touching objects. The scientists then investigated how long the virus remained infectious on these surfaces.
Much of the data from this study was made public prior to publication in the journal due to the severity of the COVID-19 pandemic.
The National Institute of Allergy and Infection Disease, a division of the National Institutes of Health, sought to compare SARS-CoV-2 to SARS-CoV-1, the virus that causes SARS. SARS-CoV-1 is the human coronavirus most closely related to SARS-CoV-2. The scientists wanted to understand how the environment impacted both strains. SARS-CoV-1 was eradicated by intensive contact tracing and case isolation measures and no cases have been detected since 2004, the NIH noted. However, the scientists quickly pointed out that “in the stability study the two viruses behaved similarly, which unfortunately fails to explain why COVID-19 has become a much larger outbreak.” When SARS-CoV-1 emerged, it infected more than 8,000 people in 2002 and 2003, NIH said. COVID-19 has now infected more than 200,000 people, according to the Johns Hopkins virus tracking map. Of the 201,634 people infected, the majority are in China, Italy and Iran. There are 6,496 cases in the United States. The number of deaths from the disease has now topped 8,000.
Some of the observations from the study have potentially shed light on why COVID-19 is spreading faster than SARS did. The first observation is that infected individuals are likely to spread COVID-19 while being asymptomatic. This makes disease control measures that were effective against SARS-CoV-1 less effective against its successor, the NIH said. That reinforces the idea of social distancing and self-isolation.
While many cases in the United States and abroad have been associated with long-term care facilities and healthcare settings, the researchers said most secondary cases of virus transmission of SARS-CoV-2 appear to be occurring in community settings, as opposed to healthcare facilities.
The findings affirm the guidance from public health professionals to use precautions similar to those for influenza and other respiratory viruses to prevent the spread of SARS-CoV-2, NIH said.