COVID-19: Prevention and risks

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How COVID-19 spreads

COVID-19 spreads from an infected person to others through respiratory droplets and aerosols that can vary in size, such as:

These respiratory droplets and aerosols are created when an infected person:

COVID-19 can also spread by touching something that has the virus on it, then touching your mouth, nose or eyes with unwashed hands.

You can transmit COVID-19 before you start showing symptoms or without ever developing symptoms.

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Animals

We’re still learning about the COVID-19 virus in animals. Based on available information to date, animal-to-human transmission is likely very uncommon.

People with COVID-19 can spread the virus to animals during close contact. To prevent possible infection, anyone with suspected or confirmed COVID-19 should avoid contact with:

  • household pets
  • other animals, including feeding wildlife

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Food

There's currently no evidence to suggest that food is a likely source of COVID-19, as there are no reported instances.

We're continually working to examine new scientific evidence between food safety and COVID-19. Scientists and food safety authorities around the world are also working closely to share information on COVID-19 and its relation to food safety. We'll continue to update Canadian food safety practices based on the most relevant and recent scientific findings.

Individual measures such as hand hygiene can help to reduce the risk of foodborne illnesses.

If we become aware of a potential food safety risk, we'll take appropriate actions to ensure the safety of Canada's food supply.

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Vaccination

Evidence shows that the vaccines used in Canada are very effective at preventing severe illness, hospitalization and death from COVID-19.

It's important to receive a primary series and a booster dose (or doses) when eligible for the best protection against COVID-19.

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Individual public health measures

Individual public health measures are effective actions you can use every day to help reduce the spread of COVID-19. These measures are also sometimes called personal preventive practices. It’s most effective to use several measures at once, which is called layering.

Governments and public health authorities across Canada continue to adjust their public health advice based on their local situations. This includes easing of public health requirements. For this reason, you’ll need to make your own decisions about which personal measures to take to reduce your risks. It’s important to:

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Why these actions are still important

Following these actions remains important for many reasons. COVID-19 will continue to spread at different levels in our communities, and outbreaks will still occur. New variants of concern may also emerge.

There’s also uncertainty around how long immunity from vaccination and previous infection lasts.

Some settings will continue to be higher risk, including crowded and poorly ventilated public spaces. The risk is higher if activities like singing or shouting, or ones that make people breathe heavily, are occurring.

The consequences of COVID-19 transmission may be greater in some populations and settings. These include people in group living settings and those at risk of more severe disease or outcomes. Following individual public health measures helps to protect these populations.

Post COVID-19 condition

Following individual public health measures can help reduce the risk of infection from COVID-19.

Some people who become infected with COVID-19 may experience long-term symptoms, even after they recover from their initial infection. This is sometimes called post COVID-19 condition or long COVID.

Studies are underway to further understand what causes post COVID-19 condition and how to diagnose and treat it.

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People who are at risk of more severe disease or outcomes

You may be at risk of more severe disease or outcomes from COVID-19 if you:

If so, it’s even more important that you reduce your risk of exposure to the virus. This means you should use all individual public health measures and continue to:

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Stay at home when you're sick

Stay home and limit your contact with others when you’re sick or experiencing any COVID-like symptoms, even if mild. This will help prevent others in your community from getting sick.

If you have to share spaces with others, even while at home, use individual public health measures, such as:

  • wearing the best quality and best fitting respirator or mask available to you
    • those you’re sharing a space with should also wear the best quality and best fitting respirator or mask available to them
  • keeping the space well ventilated

Rapid tests may be used to quickly identify if you have COVID-19, and isolate if the result is positive. Follow your local public health authority’s testing directions.

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Wear a well-fitting respirator or mask

Properly wearing a well-constructed, well-fitting respirator or mask can help:

  • contain your respiratory particles
  • prevent or reduce respiratory particles you inhale

We recommend that you wear a mask in public indoor settings. You should feel free to wear a mask even if it’s not required in your community or setting.

It’s especially important to wear a mask if you’re:

  • at risk of more severe disease or outcomes
  • around others who are at risk of more severe disease or outcomes
  • visiting a group living setting
  • in a crowded or poorly ventilated setting

Choose the best quality and best fitting respirator or mask available to you.

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Improve indoor ventilation

Good ventilation exchanges indoor air for outdoor air. This helps reduce the buildup of potentially infectious respiratory particles in the air indoors. Opening windows or doors if possible, even for a few minutes at a time, can improve ventilation.

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Practise respiratory etiquette and hand hygiene

Respiratory etiquette means, when coughing or sneezing, you should:

  1. cough or sneeze into a tissue or the bend of your arm, not your hand, if you're not wearing a mask
  2. throw any tissues you've used into a plastic-lined waste container as soon as possible
  3. clean your hands immediately afterwards

Hand hygiene means washing your hands regularly with soap and water for at least 20 seconds. If soap and water aren't available, use a hand sanitizer containing at least 60% alcohol. For example, clean your hands:

  • before and after touching a mask
  • before touching your eyes, nose or mouth
  • after using the washroom
  • after touching frequently touched surfaces and objects
  • after coughing or sneezing
  • before and after eating or handling food

Avoid touching your eyes, nose or mouth with unwashed hands.

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Clean and disinfect surfaces and objects

Surfaces and objects are more likely to become contaminated with COVID-19 the more often they’re touched. Cleaning and disinfecting them can inactivate the virus, making it no longer infectious.

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Community-based public health measures

Recommendations and practices may vary for some settings as governments and public health authorities adjust community-based public health measures. If you operate a non-health care community setting that the public can access, you should:

These settings may include:

Always follow and respect the measures a specific setting has put in place.

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Group living settings

Businesses and workplaces

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