We may think that our beds and bedding are cozy and comfortable, but they may not be as clean as we think. More often than not, there are a lot of germs lurking in and around them. These microorganisms are often shed from our bodies and find their way into our bedrooms where they become entrapped into the porous sheets, duvet, pillow and even bedhead materials. And it’s not only a one-way transfer process. Once contaminated, the water vapour our bodies naturally give off can also transfer and provide the water source for these bacterial, fungal and yeast cells to multiply.
Germs are not only found in our bedrooms and bed linen but elsewhere in our homes. They’re everywhere - in the air and on surfaces - and in every building including hospitals. When these germs are transmitted from surfaces to the body this is called fomite transmission. This hand to mouth disease transmission from surfaces onto the fingertips is highly efficient showing 33% efficiency for both bacteria and viruses.
A well-known study showed that in a hospital, even clean linen is a problem with about 55% of bed linen becoming contaminated before contact with a patient using the bed for the first time. Microbiologists measure contamination by pressing Petri plates onto areas of interest or swabbing over a known area. This way they can assess the number of germs that are there (and can grow) on a centimetre by centimetre basis. The index used is germs (or colony forming units) per centimetre squared, CFU/cm2. Clean linen has approximately 0.1 colony-forming units per square centimetre, while dirty linen has lots of microbes, up to 1 colony per centimetre square. However, staff uniforms and clothing are known to contain an even higher number of microbes of up to 2 colony-forming units per centimetre square.
Nearly 60% of the identified Species of these disease-causing bacteria could be opportunistic pathogens and a risk for people with weakened immune systems.
This is really important and the latest research about immune status shows across nearly 27,000 people diagnosed with COVID-19, those persons most at risk for serious illness have specific quantities of a white blood cell called lymphocytes. We already know that lymphocytes help your body fight infections and that lymphocyte levels determine inflammation status. This paper, then shows that low to very low leucocyte levels predict COVID severe outcomes; while the reverse is also true, and those persons with high levels of leucocytes may develop the cytokine storm phenomenon which also has worse outcomes.
However, in the era of COVID-19, there’s the potential for people suffering from SARS-CoV-2, which is the specific coronavirus responsible for COVID-19, coming in contact with bed linen and other porous and semi-porous materials in the home and bedroom.
By looking at the mode of transmission of the novel coronavirus, a connection has now been established between material type and how long the SARS-CoV-2 virus can survive outside of a host.
A study by the Commonwealth Scientific and Industrial Research Organization (CSIRO), an Australian government agency responsible for scientific research, looked at how long the virus remained infectious on six common surfaces, namely cotton, glass, steel, vinyl and paper and polymer banknotes.
A droplet of liquid containing SARS-CoV-2 was placed on multiple small test surfaces and left for up to 28 days. The different materials were recovered and placed in tissue culture to observe if any infectious virus remained. Importantly, there was a clear correlation between temperature and virus recovery. For cloth, at 20°C, the virus was infectious up to day 14; at 30°C up to 3 days; while at 40°C, the virus was only infective for 16hrs. These results were obtained under laboratory conditions with no exposure to ultraviolet light and humidity controlled at 50%.
The point here is that the virus depends largely on temperature for survival. The cooler the temperature, the longer the virus remains infectious on different materials. This can be up to 28 days on non-porous surfaces like glass, steel or polymer banknotes.
Viral shedding from a SARS-CoV-2 patient can occur up to two months after symptom onset. Isolation at home means potentially infected people are in bed for longer with high chances of spreading the virus through bed sheets and pillowcases. Shedding occurs mainly through respiratory droplets emitted from the nose and the throat but between 1 and 20% of patients with coronavirus disease have skin lesions. The research showed that the virus was highest in the sweat glands and sweat ducts and hence there is a potential risk of viral transmission via perspiration and skin contact.
Therefore, the importance of washing machine temperature cannot be underestimated. Lower temperature washing cycles can only be compensated for by extending the wash cycle time for much longer periods. The importance of heat therefore cannot be denied and I recommend a temperature/cycle time optimum of 60°C for at least 45 minutes for the main wash cycle.
By comparison, the influenza virus remains viable depending on the type of material. According to research on the survival of a pandemic strain of Influenza A (H1N1) on a variety of common household surfaces where multiple samples were taken from four types of common household fomite at seven-time points. The results showed that Influenza A (H1N1) virus particles remain infectious for 2 days on a wooden surface, 1 day on stainless steel and plastic surfaces, and 8 hours on a cloth surface. Virus recovery from the cloth was suboptimal probably due to the differences in surface roughness of the different fibres.
These findings suggest that pandemic Influenza A (H1N1) can survive on common household fomites for extended periods of time, and that good hand hygiene and regular disinfection of common, high-touch surfaces should be practised during this pandemic (as well as cold and flu season) to help reduce transmission.
Here are a few tips for good bed hygiene:
If you follow the above tips, you’ll reduce the chances of spreading disease-causing organisms through bed linen in particular, and other fomites on towels, money, clothing, dishes, books or toys in general.
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