COVID-19 is the shortened name of coronavirus disease 2019. It is a pandemic illness caused by a coronavirus. The virus that causes COVID-19 is severe acute respiratory syndrome coronavirus 2, shortened to SARS-CoV-2 and it began spreading in 2019. The COVID-19 virus spreads most commonly through the air between people in close contact.

The most effective way to protect yourself and others from getting COVID-19 is to follow the recommendations for getting a CDC vaccine.

How does the coronavirus spread?

Coronaviruses are a group of viruses that cause respiratory illnesses. For example, they can cause the common cold and severe acute respiratory syndrome, shortened to SARS, as well as COVID-19.

The virus that causes COVID-19 spreads mainly from person to person. It can spread from someone who is infected but has no symptoms. When people with COVID-19 cough, sneeze, breathe, sing or talk, they send out virus-infected particles from the respiratory system. People who breathe in the particles or have them land on their hands, nose or mouth can catch the COVID-19 virus.

In areas with low air flow, these particles may collect in the air for minutes to hours.

What are the symptoms of COVID-19?

Typical COVID-19 symptoms often show up 2 to 14 days after contact with the virus. They include the loss of taste and smell and a hard time breathing or catching your breath. People also generally have cold-like symptoms and may have upset stomach, vomiting or loose stools, called diarrhea.

People may only have a few symptoms or none. Other people may have serious symptoms that must be treated in the hospital.

Get emergency help right away for any of the following symptoms:

• Can't catch your breath or have problems breathing.
• Skin, lips or nail beds that are pale, gray or blue, depending on skin color.
• New confusion.
• Trouble staying awake or waking up.
• Chest pain or pressure that is constant.

This list doesn't include every emergency symptom. If you or a person you're caring for has symptoms that worry you, get help.

Can COVID-19 be prevented?

Getting a COVID-19 vaccine protects against serious illness, the need for hospital care due to COVID-19 and death from COVID-19. Staying up to date with the latest vaccine is most important for people at higher risk. That includes adults over age 65, those with weakened immune systems, people who are pregnant, and people with chronic conditions, such as heart disease, lung disease or obesity.

Serious side effects from the COVID-19 vaccine are extremely rare. Because of that, even healthy adults benefit from the COVID-19 vaccine, which lowers the risk of serious illness at a rate similar to that of the flu vaccine.

What can I do to avoid becoming ill?

The most effective way to avoid getting COVID-19 is to get the COVID-19 vaccine.

Other ways to avoid COVID-19 are to:

• Avoid close contact with anyone who is sick or has symptoms.
• Wash your hands often using soap and water for at least 20 seconds. Or use an alcohol-based hand sanitizer with at least 60% alcohol.
• Clean and disinfect surfaces that are often touched, such as doorknobs.
• Try to spread out in crowded public areas, especially in places with poor airflow.

Should I wear a mask?

In general, masks can slow the spread of viruses that cause respiratory diseases, including COVID-19. Masks help the most in places with low air flow and where you are in close contact with other people.

Wear a mask when you're inside a crowded place with poor airflow. This is most important when many people in the area are sick with COVID-19 or the flu. Also, during travel, masks can help if the places you are traveling to or through have a high level of illness.

What can I do if I have or may have COVID-19?

Contact a healthcare professional if you test positive for COVID-19. If you have symptoms and need a test, or you've been exposed to someone with COVID-19, a healthcare professional can help. People who are at high risk of serious illness may get medicine to block the COVID-19 virus from spreading in the body. Or your healthcare team may plan regular checks to monitor your health.

In the United States, COVID-19 tests are available at stores and pharmacies or can be ordered online. COVID-19 tests also are available from healthcare professionals, some pharmacies and clinics, or at community testing sites.

The U.S. Food and Drug Administration, also known as the FDA, approves or authorizes the tests. On the FDA website, you can find a list of the tests that are validated and their expiration dates. You also can check with your healthcare professional before buying a test if you have any concerns.

Oct. 24, 2025

Original article: https://www.mayoclinic.org/diseases-conditions/coronavirus/expert-answers/novel-coronavirus/faq-20478727