The SARS-CoV-2 virus
This article was last modified on

SARS-CoV-2, the novel coronavirus that causes the pneumonia-like illness COVID-19, emerged at the end of 2019. The virus spread at an alarming rate, prompting the World Health Organization to declare the outbreak a pandemic and the U.S. Department of Health and Human Services to declare a public health emergency. Use these resources to help understand COVID-19 and be proactive about prevention.

CDC COVID-19 County Check

Find out about the level of COVID-19 transmission in your area

How to Use a Rapid At-Home COVID-19 Test Kit

January 12, 2022

With the spike in demand for convenient, timely COVID-19 testing, many Americans will be using at-home self-testing kits in the coming days and weeks to determine whether they are infected with the SARS-CoV-2 virus.

While using an at-home self-testing kit provides the most rapid results, it is critical to perform the test properly for accurate results. Here are some tips for using at-home testing kits:

  • Be sure to check the expiration date on the test kit and don’t use it if it has expired.
  • Find and follow the directions for storing the test kit until you are ready to use it. Some kits may not be valid if they are exposed to high or low temperatures and humidity.
  • Fully read the instructions for performing the test before you begin so that you understand what you need to do for each step. Some testing kit instructions include links to online videos or tutorials that you can watch in advance of testing.
  • Make sure you have everything you need before starting the test. For example, have a timer ready because you will likely need to time some of the steps of the test.
  • Thoroughly wash your hands and the surface where you will be doing the test before you begin.
  • Carefully follow the instructions for collecting your sample. Some kits use nasal swabs, while few use saliva samples. Read more about the proper collection of nasal swabs.
  • Follow the test instructions and perform each step as directed. Be sure to time the steps accurately. Failing to do so may lead to false results.
  • Once you are done and have your result, dispose of the swab and other testing items in the trash. Clean the testing surface and wash your hands again.

If your result is positive, you should isolate yourself, staying away from others, even if you don’t have symptoms. Read the information on isolation in the next section below. You should also notify a health care provider that you have a positive test result. If symptoms worsen and your illness becomes severe, seek medical care. If you develop serious symptoms like difficulty breathing, get medical attention right away. has several resources that can answer frequently asked questions such as:

  • When should I get an at-home COVID-19 antigen test?
  • How accurate are at-home COVID-19 tests?
  • What is the difference between at-home COVID-19 antigen tests and PCR tests?
  • What are some of the best at-home COVID-19 tests?
  • How do I interpret my results?

For the answers to these and more, read the articles:

Centers for Disease Control and Prevention. Self-testing. Updated Dec. 29, 2021. Accessed January 12, 2021.

COVID-19 News and Spotlights

CDC Shortens Some COVID-19 Quarantine and Isolation Times

January 4, 2022

On December 27, 2021, the Centers for Disease Control and Prevention updated and shortened some of the recommended periods for COVID-19 isolation and quarantine. Scientists are continually studying and learning more about SARS-CoV-2, the virus that causes COVID-19. The following table summarizes the recommendations based on the current science for when a person is most contagious and what to do if you are exposed to or infected with the virus.

Quarantine Isolation
Definition Staying away from others who are from outside your home Staying away from others even those inside your own home
When to do it After close contact with someone who has COVID-19. Close contact means being within 6 feet for 15+ minutes over 24 hour period After contracting COVID-19 even if no symptoms (i.e. positive COVID-19 test), regardless of whether you have been vaccinated
What to do if  Fully vaccinated and boosted: You do not need to quarantine unless you have symptoms. Whether or not you have symptoms: 

  • Get tested 5 to 7 days after exposure if possible
  • Wear mask indoors in public for 10 days or until negative test, whichever is sooner
You have a positive test but no symptoms: Isolate 5 days followed by 5 days wearing a mask when around others. If you develop symptoms, follow directions below
What to do if  NOT fully vaccinated and boosted: 5 day quarantine followed by 5 days wearing a mask

  • If you can’t quarantine, wear a mask for 10 days
  • Watch for symptoms (fever, cough, shortness of breath)
  • Get tested 5 to 7 days after exposure if possible
You have symptoms and think or know you have COVID-19

  • Isolate at least 10 days after symptoms first appeared and
  • Isolate at least 24 hours with no fever and using no fever-reducing drugs and symptoms improve

*Fully vaccinated is defined as receiving a full series of one of the approved vaccines. 

Centers for Disease Control and Prevention, CDC Updates and Shortens Recommended Isolation and Quarantine Period for General Population, (December 27. 2021) Media Statement. Accessed January 4, 2021.

Centers for Disease Control and Prevention, COVID-19 Quarantine and Isolation. (Updated December 9, 2021). Accessed January 4, 2021.

CDC COVID-19 Self-Checker

Answer questions to help you decide whether to seek medical care and get tested. To get started, click the button below:

COVID-19 Vaccines

For the latest information on COVID-19 vaccines, see this CDC page.