MHLW guidelines – How to sterilize your home against Norovirus


You may have noticed on the news that Norovirus has been spreading rapidly around Tokyo. Many of my friends and their babies have had it over the last 10 days, and my baby also came down with vomiting and diarrhea on the weekend.

Here is an important leaflet from the Japanese Ministry of Health, Labour and Welfare (MHLW):

MHLW Leaflet about Norovirus

MHLW leaflet about Norovirus P1

MHLW leaflet about Norovirus P2

The MHLW leaflet is all in Japanese, but is an excellent fact sheet, so we decided to translate some of the key points:

  • Symptoms appear 24 to 48 hours after exposure.
  • Special care needs to be given in the case of babies and elderly people, who might inhale their vomit and suffocate or contract pneumonia.
  • Wash your hands thoroughly with soap after going to the toilet, before cooking food, before eating
  • When you wash your hands, be careful to wash the places that easily collect dirt – between fingers, under finger nails, around wrist

How to kill the virus? 

There are 2 methods:

1). Disinfection by chlorine

– Wipe with a cloth moistened with hypochlorous acid with chlorine level 200ppm

How to make hypochlorous acid with chlorine level 200ppm?

– Fill a 3L pet bottle with tap water, and then pour in 10m chlorine bleach (6% concentration kitchen bleach). You can find kitchen bleach (called “kitchen haita” in Japanese) in supermarkets, drug stores or convenience stores in Japan. Here is the link to kitchen bleach on Amazon Japan.

Cleaning products – Kitchen bleach, disposable mask, gloves & cloth

2). Heat

– For the prevention of food poisoning caused by norovirus, MHLW recommends that foods be subjected to heat treatment at higher than 85°C for 1 min or more.

How to avoid spreading Norovirus?

1. Sterilization

Wash/sterilize the following items of the infected person separately:

  • Used towel
  • Cloth, towel, or anything that has been contaminated
  • All dishes which the infected person used needs to be sterilized with hypochlorous acid with chlorine level 200ppm.
  • Curtains, clothes, and door knobs must be sterilized with hypochlorous acid with chlorine level 200ppm.
  • For clothes washing, soak the clothes in water with detergent and wash slowly with your hand (using glove) before using washing machine. If you use a chlorine based detergent, or wash the clothes for 1min in hot water (more than 85 degrees celcius), it is much more effective. Placing washed clothes in a dryer with high temperature will also help to kill the virus.

2. Vomit clean-up

When you clean-up vomit, follow these guidelines:

  • Wear disposable mask and gloves
  • Clean-up with paper towel, wipe with a cloth soaked with hypochlorous acid with chlorine level 200ppm, and then wipe with clean damp cloth
  • Put vomit and disposable mask and gloves into plastic bag, and tie strongly in a knot. If you can put hypochlorous acid with chlorine level 1000ppm, it will be much better for killing the virus.
  • Be careful not to get splashed when infected person vomits
  • When you finish clean up, wash your hands carefully

How to make hypochlorous acid with chlorine

Here is a demonstration by Tomoko on how to make kitchen bleach solution, following MHLW guidelines, for sterilizing your home of Norovirus:

For Industry Use – using bleach with concentration 12%:

  • 5 ml + 3L water -> sterilization for dishes, curtain, door nob, floor, etc
  • 25ml + 3L water -> dispose vomit

For Household use – using kitchen bleach with concentration 6%:

  • 10 ml + 3L water -> sterilization for dishes, curtain, door nob, floor, etc
  • 50ml + 3L water -> dispose vomit

*Make sure you check the “how to use” label on the product before using.

*Vomit is acidic, so it may cause poisonous fumes if you use full concentration bleach.

More information:

Thank you Shaney for forwarding the MHLW and CDC links to us!

And thank you Tomoko for translating and for the excellent video showing how to clean up following the MHLW guidelines!!

Take extra care everyone!!!

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2 thoughts on “MHLW guidelines – How to sterilize your home against Norovirus

  1. Elisabeth says:

    I am a little bit confused and disturbed by the sterilising methods though…please correct me if I am wrong, but from what I know hypochlorous acid can be quite hazardous, particularly on the respiratory system and those with asthma, and can be corrosive to the eyes and skin (as chlorine generally is – think red eyes in a chlorinated swimming pool). And using bleach with young babies in the house, no matter how weak, isn’t recommended. I think some far safer alternatives, that are just as effective, would be to use Eucalyptus oil or tea tree oil.

  2. Erin says:

    Hi Kate, great idea to pass on information about norovirus. When my little girl has the vomits I also try and rinse her mouth with fresh water straight away, as the acid in the vomit can cause ulcers inside the mouth.
    Sorry to hear your baby is sick too, hope he feels better soon. Thanks Erin

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