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Japan health official advises best ways to wash hands, clothes to limit virus spread

Michihiro Nishida, the head of the Saitama public health center, is seen in the city of Saitama on Feb. 25, 2020. (Mainichi/Shoko Washizu)

SAITAMA -- With infections from the new coronavirus continuing to spread across Japan, the importance of hand-washing as an effective preventative measure against the disease is being emphasized.

To find out why hand-washing is so important in the fight with this virus and to also clear up a few common questions readers may have about limiting the coronavirus' spread, I spoke to Michihiro Nishida, the head of the Saitama public health center.

Question: Why is hand-washing so effective against the virus?

Michihiro Nishida: There isn't any data specific to the new coronavirus yet, but if it has similar characteristics and behavior to other strains of coronavirus, then it can be killed by surface-activating agents, such as soap. Alcoholic hand sanitizers are also effective. This is why both the World Health Organization (WHO) and the Ministry of Health, Labor and Welfare are encouraging people to first wash their hands and then use alcoholic hand sanitizers.

Q: Is it OK to just run your hands under running water?

MN: It's better than not doing it. But, take care to thoroughly rub your hands together. You can expect some effect even if you just rub your hands under running water. Think of it like when you want to get ink off your hands, it's more effective to scrub your hands together than to just put them in water.

So, it's good to wash and rub your hands for about 30 seconds or more. The best way to clean your hands is to use soap and running water to remove any grime, and then apply alcoholic hand sanitizer after having thoroughly dried your hands. This way, you kill off remaining viral agents.

Q: Is it OK to just use alcoholic hand sanitizers?

MN: When alcohol evaporates, it kills the virus. When applying alcoholic cleaning products to your hands, rub them in. It is effective when it dries, so apply it to dry hands rather than wet ones.

Q: If the virus is on clothes, desks or other objects, how long can it live for?

MN: In the case, for example, of the norovirus that causes gastroenteritis, alcohol is ineffective against it, and it stubbornly refuses to die to the extent that it can remain in an infectious state on desks and clothes for around one to two weeks.

We don't yet know the new coronavirus' survival period out in the environment, but it's not thought to be as long as that of the norovirus. But, like the norovirus, it's weak against chlorine bleaches, and it's thought that a single wipe from a cloth with diluted bleach on doorknobs or elevator buttons can kill the virus.

Q: If someone thought the virus was on their clothes, what would you suggest they do?

MN: It's fine to put your clothes in the washing machine as you would ordinarily. Additionally, it's advisable to dry your clothes outdoors in the sun. It's thought that viral particles can only live out in the air for a few minutes at most because they have no source of sustenance in the atmosphere.

For this reason, rather than shutting up your home, it's thought that ventilation which gets the air out is more effective. People may think that the virus can enter their own homes from the rooms of their neighbors, but its potency is weakened in the air, so it's alright.

Q: If you're concerned that you might have been infected, what should you do?

MN: Even if you are infected you may not exhibit symptoms, and even among people who do show symptoms many of them will have only mild ones. In the same way as with a typical cold or bout of influenza, symptoms tend to subside around four days after developing.

If after that time frame however your fever has not started to ease, then it's possible your illness has become more serious, and it's then that you should seek an examination from a medical facility.

Unlike influenza, there is no established course of action that says you should return to school or work after a specified number of days from your fever breaking. I think there will be a decision on how long that should be in the near future.

I also suspect that people who are well and healthy should as much as possible avoid going to places where there are many people with weakened or compromised immune systems, such as to hospitals or care facilities for elderly people. Even if you feel fine, there is a chance you are infected with the virus, so it's essential that people bear in mind that they shouldn't bring the virus with them to places.


Michihiro Nishida began working at the Ministry of Health, Labor and Welfare in 1990. He served as the deputy director of the health and welfare department at the Tottori Prefectural Government and Saitama public health center's regional health section director, and has from 2010 served in his current role at the city of Saitama public health center.

(Interviewed by Shoko Washizu, Saitama Bureau)

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