A new virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the cause of a disease outbreak that began in China in 2019. The disease is called coronavirus disease 2019 (COVID-19).

In March 2020, the World Health Organization (WHO) declared COVID-19 a pandemic. Public health groups, including the U.S. Centers for Disease Control and Prevention (CDC) and WHO, are monitoring the spread of the COVID-19 virus and posting updates on their websites.

How does the coronavirus spread?

Data has shown that the COVID-19 virus mainly spreads from person to person among those in close contact. The virus spreads by respiratory droplets released when someone infected with the virus coughs, sneezes, breathes, sings or talks. These droplets can be inhaled or land in the mouth, nose or eyes of a person nearby.

Sometimes the COVID-19 virus can spread when a person is exposed to small droplets or aerosols that stay in the air for several minutes or hours — called airborne transmission.

The virus can also spread if you touch a surface with the virus on it and then touch your mouth, nose or eyes. But the risk is low.

The COVID-19 virus can spread from someone who is infected but has no symptoms. This is called asymptomatic transmission. The COVID-19 virus can also spread from someone who is infected but hasn't developed symptoms yet. This is called presymptomatic transmission.

It's possible to get COVID-19 twice or more.

What are the symptoms of COVID-19?

COVID-19 symptoms can be very mild to severe. Some people have no symptoms. The most common signs and symptoms are fever, cough, tiredness, and loss of taste or smell.

Other signs and symptoms may include shortness of breath, muscle aches, chills, sore throat, headache, chest pain, diarrhea, vomiting and nausea. This list is not complete. Other less common symptoms have also been reported. Symptoms may appear 2 to 14 days after exposure.

Can COVID-19 be prevented?

The CDC recommends a COVID-19 vaccine for everyone age 6 months and older. The COVID-19 vaccine can lower the risk of death or serious illness caused by COVID-19. It lowers your risk and lowers the risk that you may spread it to people around you.

The COVID-19 vaccines available in the United States are:

• 2023-2024 Pfizer-BioNTech COVID-19 vaccine, available for people age 6 months and older.
• 2023-2024 Moderna COVID-19 vaccine, available for people age 6 months and older.
• 2023-2024 Novavax COVID-19 vaccine, available for people age 12 years and older.

What can I do to avoid becoming ill?

There are many steps you can take to reduce your risk of infection from the COVID-19 virus and reduce the risk of spreading it to others. WHO and CDC recommend following these precautions:

• Get vaccinated.
• Avoid close contact with anyone who is sick or has symptoms.
• Keep distance between yourself and others when you're in indoor public spaces.
• Avoid crowds and indoor places that have poor airflow (ventilation).
• Wash your hands often with soap and water for at least 20 seconds. If you're not able to wash your hands, use an alcohol-based hand sanitizer that contains at least 60% alcohol.
• Wear a face mask in indoor public spaces if you're in an area with a high number of people with COVID-19 in the hospital. The CDC recommends wearing the most protective mask possible that you'll wear regularly, fits well and is comfortable.
• Cover your mouth and nose with your elbow or a tissue when you cough or sneeze. Throw away the used tissue. Wash your hands right away.
• Avoid touching your eyes, nose and mouth.
• Clean and disinfect often-touched surfaces regularly.

If you have a chronic medical condition, you may have a higher risk of serious illness. Check with your health care professional about other ways to protect yourself.

Should I wear a mask?

If you're in an area with a high number of people with COVID-19 in the hospital, the CDC recommends wearing a well-fitted mask indoors in public.

Using masks in public may help reduce the spread from people who don't have symptoms. The CDC says that you should wear the most protective mask possible that you'll wear regularly, fits well and is comfortable. Respirators such as nonsurgical N95s give the most protection. KN95s and medical masks provide the next highest level of protection. Cloth masks provide less protection. The CDC says that surgical N95 masks should be reserved for health care professionals.

You are considered up to date with your vaccines if you have gotten all recommended COVID-19 vaccines when you become eligible.

The CDC recommends that you wear a mask while on planes, buses, trains and other forms of public transportation.

Can I travel?

If you're planning to travel, check for travel advisories and use appropriate precautions when in public. You may want to talk with your health care team if you have health conditions that make you more susceptible to respiratory infections and complications.

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

If you develop symptoms or you've been exposed to the virus that causes COVID-19, contact your health care professional for medical advice. Your health care team will likely recommend that you get tested for COVID-19. If you have emergency COVID-19 symptoms, such as trouble breathing, seek care immediately. If you need to go to a hospital, call ahead so that health care professionals can take steps to ensure that others aren't exposed.

Take the following precautions to avoid spreading the virus that causes COVID-19:

• Stay home from work, school and public areas and stay in isolation, except to get medical care.
• Avoid public transportation, taxis and ride-hailing services.
• Wear a cloth face mask around other people or pets.
• Wash your hands frequently with soap and water for at least 20 seconds.
• Isolate yourself as much as possible from other people or pets in your home.
• Use a separate bedroom and bathroom if possible.
• Avoid sharing dishes, glasses, bedding and other household items.
• Clean and disinfect often-touched surfaces daily.

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Nov. 04, 2023 See more Expert Answers