SARS-CoV-2 virus lives from 4 hours to 3 days in the environment but will be killed in just 1 minute with

Covid-19 is a respiratory disease, meaning it is usually spread by droplets when an infected person coughs or sneezes into the environment. These droplets carry the virus that can fall into anyone's nose or mouth when they inhale them.

But a person can also become infected with Covid-19 if they touch the surface or objects covered with droplets containing the virus on them, then touch their eyes, nose, or mouth. That's a question that since the outbreak of Covid-19, scientists have been eager to answer:

How long can this SARS-CoV-2 last on surfaces?

There have previously been some estimates of the longevity of SARS-CoV-2 virus in the environment, however, they are based only on previous studies of its cousin, the SARS virus that caused the pandemic influenza. acute respiratory tract in 2003.

Until now, a team of scientists at the National Institutes of Health (NIH) announced the results of their first experiment to confirm that the virus that caused the Covid-19 epidemic could survive from 4 hours for up to 3 days in the environment, depending on a number of factors including humidity, temperature and surface adhesion.

How long can SARS-CoV-2 virus survive on surfaces?

In their study, NIH scientists compared the life expectancy of SARS-CoV-2 virus with its sibling strain SARS when present on surfaces outside the environment.

They used an aerosol injection system to simulate the scenario of droplets below 5 micrometers dispersed into the environment. Temperature and humidity are controlled at 21-23 degrees C and 65%, respectively.

Surfaces were allowed to adhere to the virus, including: polypropylene plastic, 304 stainless steel, copper metal and cardboard. These surfaces simulate the many types of surfaces in hospitals and the everyday life we ​​come in contact with.

Test results show that both strains of SARS-CoV-2 and SARS are able to live the longest on stainless steel (stainless steel) and polypropylene, the plastic used to make many items from children's toys for to car interiors. Both viruses last up to 3 days on plastic and SARS-CoV-2 survive 3 days on stainless steel.

In the cardboard-clad scenario, the SARS-CoV-2 virus lasted 3 times longer than SARS: 24 hours compared to 8 hours. But they die faster on copper surfaces. SARS-CoV-2 disappeared after 4 hours on the field, while SARS took 8 hours.

Inside the aerosol droplets, both SARS-CoV-2 and SARS viruses have a half-life of 2.74 hours, meaning that half of the viruses will die every time.

Previously, a study published in the Journal of Hospital Infection looked at the longevity of corona virus strains found on surfaces in temperatures of 20 degrees Celsius.

Accordingly, SARS can last 2 days on stainless steel, 4 days on wood, glass, and 5 days on metal, plastic and ceramic. (The researchers also discovered a strain of SARS virus that can survive for up to 9 days on plastic surfaces at room temperature.)

On aluminum surfaces, the SARS virus can survive for 2 to 8 hours. And on the surface of latex rubber, they will die after 8 hours.

Commenting on the new findings, immunologist Rachel Graham at the University of North Carolina said it was generally possible to see that the SARS-CoV-2 virus that caused Covid-19 could survive from a few hours to a few days. on surfaces.

Smooth surfaces such as door knobs and table tops are generally easier to transmit the virus. Surfaces like money, paper, and cloth may be a bit safer because a certain amount of virus will be trapped inside their porous structures.

Your smartphone, with its glass and aluminum surface, could also be a potential virus carrier. Graham recommends that people disinfect their phones, " especially if you take it to the bathroom with you".

Ambient temperature makes a big difference

Research published in the Journal of Hospital Infection also shows that temperature can be a major obstacle to the survival of SARS-CoV virus. Just increased by 10 degrees from 20 to 30 degrees C, the life time of SARS virus on steel has been reduced to half.

That's because the corona virus strains, including the new SARS-CoV-2, are causing the Covid-19 epidemic to carry a sheath: it's a lipid membrane that protects them as the virus moves from person to person. others in the air. Such covers can be dried in hot weather, and thereby kill the virus.

Graham said higher humidity, moderate temperatures and a good ventilation environment will help kill viruses attached to surfaces faster. This also explains why viruses that cause respiratory illnesses often break out seasonally: A cooler temperature helps harden their lipid membranes, better protecting the virus.

How to remove viruses from surfaces

The authors of the study published in the Journal of Hospital Infection noted that corona virus on surfaces and objects can be " inactivated " within 1 minute if we wipe them with 62% ethanol alcohol. up to 71%, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite.

" We expect a similar effect to help combat SARS-CoV-2, " they added.

Graham said these surface disinfectants could even work within 15 seconds. However, to kill all viruses on it, you will have to wait for about 5-6 minutes. However, that does not mean you have to wipe the door handle over and over for 6 minutes.

Mr. Graham said the important principle when disinfecting surfaces is to reduce the viral load attached to them below the spread threshold to cause disease. " Most commercial products labeled 'disinfectants' claim that they have a 99.9% kill rate of germs ," she said - and at this rate, they will definitely keep the The surface becomes safe.

But keep in mind, alcohol-based dry hand cleaners are not ideal for cleaning hard surfaces, as their alcohol content is not high enough. Dry handwash is designed to reduce the amount of germs on your hands and not " estimate all the oils and moisture in your skin ," Graham said. " Surface disinfectants - like Lysol, detergent - are better at disinfecting surfaces."

Limit your hand to face and wash your hands often

Graham emphasized the importance of washing your hands and not touching your face - these are the best ways you can do to minimize the chance of getting Covid-19 from surfaces.

Recent research has concluded that if a person spends 5 seconds touching the surface, where there are live influenza A viruses, 32% of the viruses living on them will likely get into their hands.

" If you're going to have a meal, make-up or play with your baby, etc., wash your hands," Graham said. She also suggested that people wash their hair if someone sneezes near them, even though the virus does not last too long in the hair.

Of course, coronavirus cannot spread through your skin, so as long as you don't touch your eyes, nose and mouth, you can prevent them. But easier said than done. " Most of us touch our face a few hundred times a day. So it's best to keep an eye on how clean your hands are ," Graham said.