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    Facts and myths disinfection and sterilization
    18-05-2020

    Facts and myths disinfection and sterilization

    In order to protect ourselves as effectively as possible, we should learn to filter information and use only those proven and reliable sources.

    However, it is not always easy to reach the source of the piece of news that appeared on the Internet. Let's try to check the most popular information related to safety during the pandemic and verify its accuracy. Which of them are facts and which are myths?


    1. The mask can be sterilized in boiling water or in the oven: MYTH

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    Even in January, Chinese websites received information published by an alleged doctor, recommending "home disinfection" of disposable masks. The recording, which was made available for the first time by a popular blogger in China, recorded over 60,000 views in January. The video instructs you on how to disinfect a mask with steam coming out of a pot of boiling water. The whole presented process takes 10 minutes. The English websites also raise the question of whether the disposable mask can be sterilized at home, e.g. in the oven, since the virus dies at 70 ° C.

    To answer the questions, several concepts need to be clarified. There are both disposable (surgical) and reusable masks with filters on the market, as well as barrier masks. We deal with each of them in a different way. The disposable mask - as the name implies - is intended for single use. Made of polypropylene nonwoven fabric, it is characterized by high air permeability and at the same time a high degree of protection. However, it retains its effectiveness for a short period. On the other hand, an improperly used or incorrectly disposed mask can be a source of infection in itself. Therefore, in hospitals, such masks are disposed of, after being sterilized in an autoclave.

    Reusable masks type FFP2 and FFP3 with a replaceable filter are products that can be reused after sterilization. However, remember to distinguish between disinfection and sterilization. Thanks to disinfection, we get rid of the majority of microorganisms from a given surface, but even carrying out this process at high temperature using home appliances can never be absolutely certain. Sterilization, i.e. the elimination of 100% of microorganisms, is performed in an autoclave. Such devices are no longer just within the domain of hospitals and medical practices. Fully professional, small, easy-to-use autoclaves are available on the market for about £1000. Such equipment can be purchased for home use. Professional autoclaves can also be found in beauty salons. Currently, some of them are used to help during a pandemic.

    2. The virus can survive on everyday objects for many hours: FACT

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    COVID-19 coronavirus can be infected through a droplet route. Remember, however, that not only direct contact with an infected person who is coughing or sneezing can lead to infection. Droplets (nasal discharge, saliva) containing the virus can settle on various objects and remain active for hours. Touching, for example, the door handle that an infected person opened the door with, and then your own cell phone, will "take" the virus with us. If we touch our face after using the phone - we can lead to infection.

    That is why the emphasis is on regular disinfection of everyday items after returning home. Let us remember that the virus can survive on various surfaces from several hours to even several days (indicating that its ability to infect decreases over time):

    • on paper and cardboard - up to 24 hours,

    • on plastic and stainless steel - 2-3 days,

    • on copper products - 4 hours.

    So let's remember about regular disinfection of items such as consumer electronics (especially the aforementioned mobile phone), payment cards, keys, glasses, etc., as well as door handles, light switches, and bell buttons.

    Some items are easily disinfected with disinfectant, while others, especially metal or plastic (of course those that do not contain electronic components) are a problem. This applies especially to metal objects whose rough surface does not allow thorough cleaning with an alcohol-based agent. The most effective method is autoclaving of items such as keys, jewellery, coins and even glasses.

    3. The virus can be active in the air: FACT

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    Although coronavirus cannot survive long outside of a human host, however, as already mentioned, it is able to survive a certain time on various surfaces. It may also be active in the air for some time. According to a study by a team of scientists from the University of California in Los Angeles, the National Institutes of Health and Princeton University, the virus can survive in the air for more than three hours (source https://www.nih.gov/news-events/news-releases/new-Coronavirus-stable-hours-surfaces). That is why it is so important to follow the safety rules - not leaving the house if not essential, keeping a distance from other people while outside, and meticulous disinfection of hands and sterilization of objects. It is also fully justified to use masks in places where the risk of infection is higher.

    We never know if the virus will end up in an outdoor item or even outerwear. Smartphones and electronic equipment should be disinfected with products designed for displays and screens, as these are elements that are particularly sensitive to both moisture and chemical agents. Wipes impregnated with such preparation or a spray can be best (e.g. 70% aqueous isopropyl alcohol solution). We wipe payment cards in a similar way, especially paying attention to the area around the microchip. For glasses, it is worth using soaked wipes with preparation for cleaning the optics. The keys can be washed in a bowl with warm water with the addition of detergent, although here the only reliable method is autoclaving.

    Remember that spraying the body with disinfectant liquids, vodka, and chlorine liquids do not protect against coronavirus. Disinfecting liquids do not work as a repellent. They do not "deter" the virus, so there is no point in prophylactically spraying the body with them. Such measures will also not kill a virus that has already entered the body. Furthermore, the use of surface disinfectants or chlorine-based agents can lead to allergic reactions, damage or irritation on the skin and mucous membranes and even the respiratory tract.

    4. Animals do not transmit coronavirus: FACT

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    WHO emphasizes that you cannot catch the COVID-19 coronavirus from pets. There is no evidence of possible transmission of COVID-19 coronavirus to humans by dogs or cats. There have been several cases of infection on an animal from a human (dog in Hong Kong, cat in Belgium). In both cases, the animals underwent infection very mildly, as did the tiger from the New York zoo, which had been infected with COVID-19 coronavirus in April (the tigress with a positive test result was infected by its guardian, who was an asymptomatic carrier).

    No possibility of transmission of the virus between animals or secondary infection of humans was found - calms the WHO (source: https://www.who.int/news-room/q-a-detail/q-a-coronaviruses#:~:text=symptoms). This would not be the first case of reverse zoonosis, that is, a disease that a person can infect an animal with. It was investigated that there is a low probability of infecting animals with the common influenza virus, angina-causing bacteria, mycobacterium tuberculosis, mumps virus or rotavirus. Such situations occur extremely rarely.


    5. The virus dies at elevated temperatures: MYTH

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    There was a lot of information in the media about the coronavirus pandemic coming to an end in April due to rising air temperatures. Unfortunately, the effect of higher temperatures on this type of virus is not yet thoroughly studied. At the same time, outbreaks in Spain, Italy, Florida or even Saudi Arabia do not seem to support this thesis.

    Due to the alleged sensitivity of the virus to warm air, there has also been informed that hand dryers producing hot air help fight the virus. This is not true - we eliminate the virus from the surface of the hands, washing them thoroughly with soap (the soap dissolves the lipid envelope of the virus) or disinfecting with an alcohol-based agent. The hand dryer does not kill the coronavirus. (source: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public/myth-busters).

    Killing the virus requires much higher temperatures. In the autoclave, thanks to the high pressure, a vapour temperature around 130 ° C can be obtained. Sterilization takes place in a hermetically sealed chamber.


    6. You can catch coronavirus through your eyes: FACT

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    As part of COVID-19 prophylaxis, the World Health Organization recommends frequent washing and disinfecting hands and refraining from touching the face in public places, especially around the nose, mouth and eyes. You can also get coronavirus through the tear ducts (source: https://www.specsavers.co.uk/coronavirus-staying-healthy). We should remember that both protective glasses and everyday optical glasses (which are not classic protection but do prevent us from touching the eye with our hands) should be sterilized from time to time so that they do not become the habitat of the virus. To ensure that no germs remain on the surface, it is best to sterilize the glasses in an autoclave.

    Research on the new coronavirus is ongoing - we learn something new every day. It is important to filter out information confirmed by research from rumours "circulating" the Internet network. Let's take care of hygiene and comply with WHO recommendations.

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