COVID-19 – stopping the spread

Like the flu, COVID-19 can be passed on from person to person. When an infected person coughs, sneezes or talks, they may create droplets containing the virus. These droplets are too large to stay in the air for long, so they quickly settle on surrounding surfaces.

You may get infected if you are close enough for the droplets to land on you, or if you touch those surfaces and then touch your mouth, nose or eyes. Public health measures to stop the spread include hand washing, cough and sneeze etiquette, not touching your face and physical (or social) distancing. 

On this page:

How does handwashing work to stop the spread?
How does soap work?
How does covering coughs and sneezes help stop the spread?
What should I do if I need to blow my nose?
How does not touching my face stop the spread?
How does cleaning surfaces work to stop the spread?
How should I clean surfaces?
How does physical distancing help stop the spread?
Should I wear a face mask to help stop the spread?

How does handwashing work to stop the spread?

You can catch germs (such as viruses and bacteria) when you touch contaminated objects or surfaces and then touch your face (mouth, eyes and nose). You can spread certain "germs" casually by touching another person. Washing your hands properly with soap and water can remove the germs from your hands and significantly reduce the spread of germs.

The key thing is to know how to do it so it works:

  • wash your hands often
  • use soap
  • take 20 seconds
  • dry your hands well.

If you don’t have access to soap and water, use hand sanitiser. Make sure it contains at least 60 percent alcohol and rub it into your hands for at least 20 seconds to ensure full coverage.

How does soap work?

When it comes to virus-busting, soap is great at getting rid of coronaviruses. Washing your hands with soap kills the virus by bursting its protective bubble. 

Chemical bonds allow bacteria, viruses and grime to stick to surfaces, including your hands. Soap molecules break these bonds and lift the bugs off your skin. That is because one end of a soap molecule bonds with water and the other with fat, and the virus has a lipid (type of fat) membrane.

When you rinse your hands, all the bugs that have been damaged, trapped and killed by soap molecules are washed away.


How does covering coughs and sneezes help stop the spread?

COVID-19 is spread by droplets. If you don't cover your cough or sneeze, the large droplets spray out and may reach other people and surfaces. They are too large to stay in the air for long, so they quickly settle on surrounding things.

If you cough or sneeze into your hand, you can then spread those droplets onto anything you touch. If you cough or sneeze into your elbow, it keeps the virus off your hands, so you won’t spread it onto things you touch.

What should I do if I need to blow my nose?

Use a tissue not a cloth handkerchief. Put any used tissues in a bin or a bag immediately. Then wash your hands thoroughly. Then dry them. This reduces your risk of the virus staying on your hands after you have blown your nose.

How does not touching my face stop the spread?

Trying to not touch your eyes, nose and mouth helps because your hands touch many surfaces and can pick up viruses, including COVID-19.

Once you have the infection on your hands, you can transfer the virus to your eyes, nose or mouth whenever you touch your face. From there, the virus can enter your body and make you sick.

How does cleaning surfaces work to stop the spread?

Coronaviruses can live for hours to days on surfaces like benches and door handles. How long it survives depends on the material the surface is made from. 

The new coronavirus, COVID-19, is still being studied, so we don’t yet know things like whether being exposed to heat, cold or sunlight affects how long it lives on surfaces. But for general guidance, we know that coronaviruses live on surfaces for different lengths of time.

Here are some examples:

  • Metal, such as door handles, jewellery, silverware: 5 days
  • Wood, such as furniture and decking: 4 days
  • Plastics, such as milk containers and detergent bottles, plastic chairs, backpacks and lift buttons: 2–3 days
  • Stainless steel, such as fridges, pots and pans, sinks and some water bottles: 2–3 days
  • Cardboard, such as courier boxes: 24 hours
  • Copper, such as coins, teakettles, cookware: 4 hours
  • Aluminium, such as soft drink cans, tinfoil and some water bottles: 2–8 hours
  • Glass, such as drinking glasses, measuring cups, mirrors and windows: up to 5 days
  • Ceramics, such as dishes, pottery, mugs: 5 days
  • Paper: The length of time varies. Some strains of coronavirus live for only a few minutes on paper, while others live for up to 5 days.
  • Food: Coronaviruses doesn't seem to spread through exposure to food. Still, it's a good idea anyhow to wash fruits and vegetables under running water before you eat them. Scrub them with a brush or your hands to remove any germs that might be on their surface.
  • Water: Coronavirus hasn't been found in drinking water. If it does get into the water supply, your local water treatment plant filters and disinfects the water, which should kill any germs.

How should I clean surfaces?

Regularly clean frequently used surfaces, such as phones, keyboards, door handles, remote controls, benches, tables, bathroom fixtures and toilets.

Use a disinfectant that is antiviral and follow instructions. Look for one that contains hypochlorite (which is the main active ingredient in bleach) or activated hydrogen peroxide (0.5%). Others may contain benzalkonium chloride, though some studies have shown this is less effective against coronaviruses.

You could also just use conventional bleach (at 0.1–0.2% available chlorine – check the back of your bottle) in water. You can also use ethanol alcohol or isopropyl alcohol. 

How does physical distancing help stop the spread?

Viruses do a really good job of spreading themselves quickly. People who have the COVID-19 virus have a period of time before they have symptoms. This means you can do a good job of helping the virus spread to a lot of other people in a short time unless you stay 2 metres from them. 

This is why the different alert levels all have some restrictions on how many people we can gather with, where we can travel and how we work. And why we are advised to stay at home in our bubbles as much as possible. 

See this animation of how to stop the spread: 

Source: The Spinoff, NZ, 2020

Should I wear a face mask to help stop the spread?

A face mask helps stop droplets spreading when someone speaks, laughs, coughs or sneezes. This includes someone who has COVID-19 but feels well or has no obvious symptoms. 

Face masks are particularly useful where there is known community transmission and people are in close proximity to each other, such as on public transport, in shops or in other confined or crowded environments.

To prevent community spread, you don’t need a medical-grade face mask. You just need a mask that will create a barrier between your mouth and nose and other people. Your mask can be either reusable and washable fabric mask or a single-use, disposable kind. 

Read more about face masks.

Learn more

The following links provide further information about stopping the spread of COVID-19. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Washing hands Unite Against COVID-19, NZ, 2020
How we're uniting Unite Against COVID-19, NZ, 2020
Basic protective measures against the new coronavirus World Health Organization, 2020
Learning modules to support your family and whānau during COVID-19  Ministry of Health, NZ, 2020

References

  1. Show me the science – now to wash your hands  Centres for Disease Control and Prevention, US, 2020
  2. How long does the coronavirus live on surfaces? WebMD, US, 2020
  3. COVID-19: face mask and hygiene advice Ministry of Health, NZ, 26 April 2020
  4. How to get rid of COVID-19 from surfaces the right way The Spinoff, NZ, 2020
  5. The Side Eye – viruses versus everyone The Spinoff, NZ, 2020
Credits: Health Navigator Editorial Team.