First, let's clear up the name.
We know it as COVID-19 (sometimes referred to as Novel Coronavirus) it is part of the coronavirus family, of which SARS and MERS are members more correctly the causative virus is called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Covid-19 is the resulting disease caused by becoming infected with SARS-CoV-2. It is a new strain of coronavirus that has not been previously identified in humans. Coronaviruses are so-called because their structure looks similar to a crown.
It is a moot point that a virus is even a living thing, many experts agree they show none of the normal functions associated with a living organism. A virus is little more than a packet of genetic material and protein surrounded by a fatty shell one-thousandth the width of an eyelash. Viruses are made up of RNA (sometimes DNA) encapsulated in a lipid shell and in the case of coronavirus protein spikes, hence the name, these lipids and proteins are known as a viral envelope. Destroying an enveloped virus takes less effort than their non-enveloped compatriots, such as the stomach-busting norovirus, which can last for months on a surface. Enveloped viruses require a host to survive so typically survive outside of a body for only a matter of days and are considered among the easiest to kill because once their fragile exterior is broken down they begin to degrade. SARS-CoV-2 is an enveloped virus so all effective sanitisation processes target the breakdown of this outer layer to achieve a kill.
Fragile Earth uses a natural organic biocide called PSLog6 which is tested, proven and certified to deliver a 99.9998% (Log6) pathogen reduction including on Coronavirus. Log6 is the highest level of efficacy for a sanitising product. The germicidal kill rate, Log, is measured as the number of pathogens, out of 1,000,000, expected to survive the sanitisation process when using the product. So as an example when using a Log 6 biocide only 1 out of every 1,000,000 pathogens may survive the sanitisation process. Read more about Log Kill and biocides here.
PSLog6, the biocide in Fragile Earth biocidal products, works by attacking (mechanically damaging) the virus’s proteins and lipids that form the external protection layer (the envelope) they do this on contact, the damage to the virus is permanent. At Fragile Earth we use PSLog6 in our complete range of biocidal personal and surface cleaners.
Hand sanitisers have a place in an overall hygiene plan especially when out and about, but for personal hygiene, there is no question that when there is access to soap and water it is a super-efficient and cheap way to remove any potential coronavirus from hands before it can lead to infection. The coronavirus does not penetrate through the skin because your outermost layer is slightly acidic, which prevents most pathogens from entering the body. Active virus present on the hand surface is most likely to be acquired through subsequent contact with eyes, mouth or nose.
Soap works so effectively because its chemistry pries open the coronavirus’s exterior envelope and cause it to degrade. The soap molecules then trap tiny fragments of the virus, which are washed away in the water. Hand sanitisers work similarly by busting apart the proteins and lipids contained in a virus.
A study recently published in the New England Journal of Medicine looked at how long it can be detected on various materials. Dylan Morris, an evolutionary biologist at Princeton University and a study co-author, says the mission was to investigate which surfaces found in medical settings might serve as a potential cesspool for infecting patients.
On surfaces, they found SARS-CoV-2 lasted for 24 hours on cardboard, 48 hours on stainless steel, and 72 hours on polypropylene a widely used plastic for packaging and consumer goods. The findings suggest the virus might last this long on door handles, plastic-coated or laminated worktops and other hard surfaces. The virus could only be detected for 4 hours on copper, a material that naturally breaks down bacteria and viruses. The study also revealed the SARS-CoV-2 and its cousin SARS, which caused a major outbreak in 2002 and 2003, last on surfaces for similar amounts of time.
Like many respiratory viruses, including flu, SARS-CoV-2 can be spread in tiny droplets released from the nose and mouth of an infected person as they cough. A single cough can produce up to 3,000 droplets. These particles can land on other people, clothing and surfaces around them, but some of the smaller particles can remain in the air. There is also some evidence that the virus is also shed for longer in faecal matter, so anyone not washing their hands thoroughly after visiting the toilet could contaminate anything they touch.
But, their study has limitations. The team examined the virus in a highly controlled lab setting. Spaces that are commonly touched, like a stair/handrail or bus pole, would contain a higher amount of the virus and present a greater risk for infection. Environmental conditions can also influence how long the virus lasts. Humidity, for example, is thought to make it harder for respiratory droplets to travel through the air, and ultraviolet light is known to degrade viruses.
The study also found that SARS-CoV-2 could persist as aerosols—tiny airborne particles—for up to three hours, though Morris clarifies larger respiratory droplets are more likely to be infectious. Viral aerosols are primarily a concern in clinical settings where certain treatments like ventilation can produce these particles. It is unlikely that these coronavirus aerosols come into play in open-air settings or public places like supermarkets.
Morris’s study didn’t include commonly touched items like clothing or produce, there is no evidence that SARS-CoV-2 can be transmitted via food, according to the U.S. Food and Drug Administration.
In studies of influenza viruses, porous items like clothes and wood didn’t contain the virus for longer than four hours. That’s because these items pull moisture away from the virus and cause it to degrade.
The CDC, the World Health Organization and other health authorities, have emphasised that both washing one's hands and cleaning and disinfecting frequently touched surfaces daily are key in preventing SARS-CoV-2's spread.. So although we still don't know exactly how many cases are being caused directly by contaminated surfaces, experts advise exercising caution.
As SARS-CoV-2 has spread, so has our fear of surfaces. There are now some familiar scenes in public places around the world – people trying to open doors with their elbows, commuters studiously surfing their way through train journeys to avoid grabbing a handle, office workers rubbing down their desks each morning.
In the areas worst hit by the new coronavirus, teams of workers in protective clothing have been dispatched to spray a fog of disinfectant in plazas, parks and public streets. Cleaning regimes in offices, hospitals, shops and restaurants have been increased. In some cities, well-meaning volunteers even venture out at night to scrub the keypads of cash machines.
Coronaviruses are well known to be particularly resilient in terms of where they can survive and researchers are now beginning to understand more about how this affects the spread of the SARS-CoV-2.
Although there is no data on how many virus particles will be in a single droplet coughed up by an infected person, research on the flu virus suggests smaller droplets can contain many tens of thousands of copies of the influenza virus. However, this can vary depending on the virus itself, where in the respiratory tract it is found and at what stage in the infection the person is.
On clothing and other surfaces harder to disinfect, it is not yet clear how long the virus can survive. The absorbent natural fibres in cardboard, however, may cause the virus to dry up more quickly than on plastic and metal, suggests Vincent Munster, head of the virus ecology section at Rocky Mountain Laboratories and one of those who led the NIH study.
“We speculate due to the porous material, it desiccates rapidly and might be stuck to the fibres,” he says. Changes in temperature and humidity may also affect how long it can survive, and so may explain why it was less stable in suspended droplets in the air, as they are more exposed. “[We’re] currently running follow-up experiments to investigate the effect of temperature and humidity in more detail.”