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Learning About Preventing COVID-19 When You Have a Weakened Immune System

What is coronavirus (COVID-19)?

COVID-19 is a disease caused by a type of coronavirus. This illness was first found in December 2019. It has since spread worldwide.

Coronaviruses are a large group of viruses. They cause the common cold. They also cause more serious illnesses like Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS). COVID-19 is caused by a novel coronavirus. That means it's a new type that has not been seen in people before.

What causes a weakened immune system?

Your immune system may not work well because of certain medicines used to treat cancer or autoimmune disease. Taking steroid medicines for a long time can also weaken your immune system. Other causes include certain health problems, as well as immune problems that run in your family.

Why is it important to take extra precautions?

A weakened immune system makes it more likely that you'll get very sick from COVID-19. And the COVID vaccine may not work as well for you.

How can you protect yourself?

Follow these guidelines until your doctor tells you it's safe to stop.

  • Get vaccinated, if you haven't already.
  • Talk to your doctor about whether you need an extra vaccine dose.
  • Avoid sick people.
  • Wear a mask if you go into public areas, especially indoor spaces.
  • Avoid crowds, and try to stay 2 metres (6 feet) apart from other people. If you have to be in a crowded area, wear a mask, even if you're outside.
  • Wash your hands often.
  • Avoid touching your mouth, nose, and eyes.
  • Ask the people you live with or who are in close contact with you to get vaccinated.
  • Ask the people you live with to wear a mask in public areas, even if they're fully vaccinated.

If you think you've been exposed, call your doctor. You may need a COVID-19 test. Your doctor may want to give you medicine to help prevent severe COVID-19.

Where can you learn more?

Go to

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