COVID-19 Variants

Multiple variants of the virus that causes COVID-19 have been documented. The Omicron variant is a new strain detected first in South Africa in November 2021, and is now circulating across the globe.

Key things to know:

  • Omicron became the dominant variant in Arizona in December 2021.
  • The Omicron variant is highly transmissible and infection can occur even if you’ve had COVID-19 previously or have been vaccinated against COVID-19.
  • While Omicron shows signs of being less severe overall, it can still cause severe illness and is very infectious. Vaccination and boosters remain the best line of defense against severe illness from COVID-19, including variants. Find a vaccine site

The Delta variant is a strain of COVID-19 that is more contagious than previous strains of COVID-19. This means it spreads from person-to-person more easily, especially if a person is not vaccinated. The Delta variant was the dominant strain of COVID-19 circulating throughout the U.S. between July and December 2021.

While anyone can become infected with COVID-19, including variants, people who have not been fully vaccinated and boosted for COVID-19 are more at risk of serious illness and death if they become infected.

The Omicron variant is significantly more contagious than the original strain of COVID-19. Mutations like Delta and Omicron occur when not enough people are vaccinated, and spread is allowed to continue. While more than half of Maricopa County residents have gotten at least 1 dose of vaccine, it's a good start, but we're a long way off from stopping future variants. We need to continue increasing vaccinations to reduce spread and prevent more variants from taking hold.

If you have already been fully vaccinated with a primary series, get your booster shot(s) as soon as you are eligible to maximize your immune protection. Vaccine is widely available in Maricopa County. Use the COVID-19 vaccine locations map to find a vaccine near you at your local pharmacy, grocery store, clinic, or community event. You can also find information about what brand(s) of vaccine are offered at each location

The COVID-19 tests that are widely available, including antigen and PCR tests, tell you if you are infected with SARS-CoV-2, the virus that causes COVID-19, but they cannot tell you which variant of the virus you are infected with. There is no commercial test available for individuals to determine which variant they have. Knowing the variant would not change how you would treat symptoms at home or guidance you would follow for home isolation.

To figure out what variant someone with COVID-19 has, the nose/throat swab or spit sample has to be sent to a special laboratory where genetic sequencing is performed. The results from the genetic sequencing test that determines the strain of COVID-19 are not allowed to be shared with a patient or family because it is not approved by the FDA. Public Health is allowed to use these results to determine what strains of the virus are circulating in our community, and if an outbreak is caused by a variant, but we cannot share the individual results of a person.

Maricopa County is working very closely with our partners to track COVID-19 genetic sequencing data to determine how variants are affecting our community. We work to get nose/throat swabs and spit samples that are positive for COVID-19 sent to specialized laboratories where they can be genetically sequenced to determine what strains of virus are in our communities. We work closely with groups and facilities experiencing outbreaks to give additional infection control recommendations and support to stop the outbreak as quickly as possible.



  • If you have a primary care provider (PCP): Report your positive home-test result to your PCP, who should report it to public health.
  • If you do not have a primary care provider (PCP): Call 602-506-6767to report your positive test and get guidance on what to do next.
  • If you are a K-12 student or staff member: Report your positive result to your school.

Antibody, or serology, tests are used to detect a past infection with COVID-19 and require a blood sample to detect the presence of antibodies. Antibody tests are not designed to detect an active infection of the virus and should not be used for diagnostic purposes.

Molecular tests, such as PCR and antigen tests, can be used to diagnose infection at the time of testing. Find a diagnostic testing location near you.

COVID-19 diagnostic testing is now widely available. You can get tested whether you are currently experiencing symptoms or are concerned you were exposed to someone with the virus, even if you have no symptoms of illness. To locate a community testing event near you or find links to testing providers, visit our testing page.

To receive up to four free at-home tests from the federal government, you can submit a request at

New testing methods have been developed since the start of the pandemic for detecting SARS-CoV-2, the virus that causes COVID-19. Some involve inserting a swab into the nose, others require a spit sample. While most labs can turn results back in two to three days, new rapid testing kits can provide results in as little as 15 minutes. The U.S. Food and Drug Administration (FDA) has approved two types of tests for diagnosing an active COVID-19 infection:

  • PCR test: This COVID-19 test detects genetic material (RNA) of the virus using a lab technique called polymerase chain reaction (PCR). PCR tests are considered highly accurate, but running the tests and analyzing the results can take time. Results may be available in as little as 24 hours or a few days depending on the lab's proximity to the testing site and other factors.

    PCR tests require that a health care worker collects fluid from the nose or throat. Many coronavirus testing sites use shorter, less invasive swabs to swab inside the nostrils and don’t go as far into the nose as the long, uncomfortable nasopharyngeal swab. Saliva-based PCR testing is now also available, where you spit into a small collection tube.

  • Antigen test (also known as rapid tests): This COVID-19 test detects certain proteins in the virus. Using a nose or throat swab to get a fluid sample, rapid antigen tests can produce results in minutes. A positive antigen test result is considered very accurate, but antigen tests have a higher chance of a false negative than PCR tests — meaning it's possible to be infected with the virus but still get a negative result. Depending on the situation, your health care provider may recommend a PCR test to confirm a negative antigen test result.

NOTE: While they sound similar, antigen tests are not the same as antibody tests. Antibody, or serology, tests are used to detect a past infection with COVID-19 and require a blood sample to detect the presence of antibodies. Antibody tests are not designed to detect an active infection of the virus and should not be used for diagnostic purposes.

Free community COVID-19 diagnostic testing is widely available and test types vary by testing site. There also may be minimum ages for certain types of tests. For more information and locations near you visit our testing page or call 2-1-1.

While they sound similar, antigen tests are not the same as antibody tests. Antibody, or serology (blood) tests are used to detect a past infection with COVID-19 and require a blood sample to detect the presence of antibodies. Antibody tests are not designed to detect an active infection of the virus and should not be used for diagnostic purposes.

COVID-19 PCR tests are very “specific,” which is a scientific term that means the likelihood of receiving false positive COVID-19 PCR result is very low. Most COVID-19 PCR tests have a false positive rate of <1%, which is extremely accurate for a laboratory test.

If you test positive for COVID-19 by a PCR test, you should assume you have COVID – even if you don’t have any symptoms! Because the test has such a low rate of false positive results, it is very unlikely that you do not have COVID.

Infected Individuals and Isolation

If you have tested positive, please visit the COVID Positive page to find out what you should do next.

Not sure how long you should isolate once you’ve tested positive? Use our Home Isolation Decision-Maker to find out.

Close Contacts and Quarantine

The Arizona Department of Health Services (ADHS) and Maricopa County Department of Public Health (MCDPH) follow CDC guidelines and define a close contact of a COVID-19 case as being:

  • You were within 6 feet of a person with COVID-19, regardless of whether masks were worn, for a cumulative total of 15 minutes or more over a 24-hour period* starting from 2 days before symptoms began (or, for asymptomatic patients, 2 days prior to test specimen collection) until the time the patient is isolated, OR;
  • You had physical contact with a person with COVID-19 while they were infectious.
    • Exception: In the K-12 school setting, a student who was within 3-6 feet of an infected student is not considered a close contact if both students were engaged in consistent and correct use of well-fitting masks at all times.
    • This exception does not apply to teachers, staff or other adults in the classroom setting.

      *Individual exposures added together over a 24-hour period (e.g., three 5-minute exposures for a total of 15 minutes).

Masks and Other Prevention Tools

Here are some things to know generally about wearing a face mask:

  • The best mask you can wear is the one that fits properly and you can tolerate for the time you need to wear a mask.
  • While wearing a mask, make sure it fits properly and that it is secure around your mouth and nose, but still allows you to breathe normally.
  • Do not re-use a disposable mask and always change it as soon as it gets damp.
  • Face masks should not be worn by children under age 2 or those who have trouble breathing, any inability to tolerate wearing it, or if they are unable to remove it without assistance.

People who are vaccinated are more protected than those who are unvaccinated; however, people who are vaccinated can still become infected and possibly infect others.

Recommended mitigation measures for COVID-19 are now outlined in CDC Community Levels. View our current community level on our dashboard at

Yes, masks help contain respiratory droplets that carry the virus, which makes us less likely to infect others. They can also protect the wearer from droplets spread by others if the masks are effective and fit well.

COVID-19 is transmitted through respiratory droplets when an infected person talks, coughs, or sneezes. These droplets can fly through the air and land in another’s person’s mouth or nose up to 6 feet away. When used with social distancing, masks can provide an extra layer to help prevent the respiratory droplets from traveling in the air and onto other people.

See the CDC comparison of mask types and the protection levels they offer.


Please see the general schools questions or questions about the school data dashboard.

COVID-19 Vaccine

Questions about vaccine locations, vaccine safety, and more? See the general vaccine FAQ.


  • Coronavirus disease 2019 or COVID-19 is a new respiratory virus first identified in Wuhan, Hubei Province, China.
  • Coronaviruses are a large family of viruses. There are several known coronaviruses that infect people and usually only cause mild respiratory disease, such as the common cold.
  • You can learn more about COVID-19 at the CDC website.

COVID-19 is thought to spread mainly through respiratory droplets produced when an infected person coughs, sneezes, or talks. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Spread is more likely when people are in close contact with one another (within about 6 feet). A person infected with COVID-19 may not show symptoms until 2-5 days after they are exposed to the virus, or may show no symptoms at all. That means a person can be spreading the virus to others without even knowing they are infected. You can help protect yourself and others by keeping 6 feet away from others, wearing a mask in public spaces, and practicing good handwashing.

Symptoms reported for patients with COVID-19 have included fever or chills, cough, shortness of breath or difficulty breathing, fatigue, muscle or body aches, headache, new loss of taste or smell, sore throat, congestion or runny nose, nausea or vomiting, and diarrhea.

Most people who contract COVID-19 will not need hospitalization. Among adults, the risk for severe illness from COVID-19 increases with age, with older adults at highest risk. There are also other factors that can increase your risk for severe illness, such as having underlying medical conditions, including heart, kidney or lung disease, diabetes, and obesity. Severe illness means that the person with COVID-19 may require hospitalization, intensive care, or a ventilator to help them breathe, or they may even die.

If you test positive for COVID-19 and have one or more health conditions that increase your risk of becoming very sick, treatment may be available. Contact a health professional right away after a positive test to determine if you may be eligible, even if your symptoms are mild right now. Don’t delay: Treatment must be started within the first few days to be effective. More information can be found here.

It’s likely that flu viruses and the virus that causes COVID-19 will both spread this fall and winter. Healthcare systems could be overwhelmed treating both patients with flu and patients with COVID-19. This means getting a flu vaccine is more important than ever.

While getting a flu vaccine will not protect against COVID-19, there are many important benefits, such as:

  • Flu vaccines have been shown to reduce the risk of flu illness, hospitalization, and death.
  • Getting a flu vaccine can also save healthcare resources for the care of patients with COVID-19.

Check with your healthcare provider or local pharmacy about flu shots in your area. Our three childhood immunization clinics around Maricopa County also have the flu shot free for anyone 6 months through 18 years of age! Please call ahead to ensure vaccine is available. It takes about two weeks to build immunity to the virus so be sure to plan ahead to make sure you and your family are protected.

At this time, there is no evidence that animals play a significant role in spreading the virus that causes COVID-19.

Based on the limited information available to-date, the risk of animals spreading COVID-19 to people is considered to be low. A small number of pets have been reported to be infected with the virus that causes COVID-19, mostly after they have had contact with people with COVID-19.

Pets have other types of coronaviruses that can make them sick, like canine (dog) and feline (cat) coronaviruses. These other coronaviruses cannot infect people and are not related to the current COVID-19 outbreak.

However, since animals can spread other diseases to people, it’s always a good idea to practice healthy habits around pets and other animals, such as washing your hands and maintaining good hygiene. For more information on the many benefits of pet ownership, as well as staying safe and healthy around animals including pets, livestock, and wildlife, visit CDC’s Healthy Pets, Healthy People website.

Children, including very young children, can develop COVID-19. Many of them have no symptoms. Those that do get sick tend to experience milder symptoms such as low-grade fever, fatigue, and cough. Some children have had severe complications, but this has been less common. Children with underlying health conditions may be at increased risk for severe illness.

A potentially severe and dangerous complication can occur in children. Called multisystem inflammatory syndrome in children (MIS-C), it can lead to life-threatening problems with the heart and other organs in the body. In this condition, different body parts, such as the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal organs, can become inflamed.

Learn more about how to recognize MIS-C.

More information: 

Still Have Questions?

If you have questions, please submit your question here or call us at 602-506-6767.