COVID-19 stands for coronavirus disease 2019. Here’s what to know about transmission, treatment, and prevention in 2024.

In 2019, COVID-19 began generating headlines worldwide because of its unprecedented transmission speed.

Its origins can be traced back to a food market in Wuhan, China, in December 2019. From there, it reached countries as distant as the United States and the Philippines.

Five years since, the coronavirus (officially named SARS-CoV-2) infection has led to more than 7 million deaths, of which more than 1 million occurred in the United States.

Read on to learn more about COVID-19:

  • how coronavirus gets transmitted
  • how it’s similar to and different from other coronaviruses
  • how to prevent transmission of coronavirus if you suspect you’ve contracted it

COVID-19 may not cause any symptoms for some people. A December 2020 literature review estimated that 17% of people with COVID-19 are asymptomatic. This means they have no symptoms at all.

Among those who do have symptoms, symptoms may appear 2 to 14 days after exposure.

Some common symptoms linked to COVID-19 include:

Less common symptoms include:

However, individuals with COVID-19 may have some, all, or none of the above symptoms.

Mild vs. severe COVID-19

The most common symptom of COVID-19 is fever. However, a 2020 study involving 213 participants with mild disease found that only 11.6% of them had a fever.

Most people with COVID-19 will only have a mild case. According to the National Institutes of Health’s COVID-19 treatment guidelines, people are said to have a mild case if they:

  • have any of the typical symptoms of COVID-19 (such as cough, fatigue, or loss of taste or smell)
  • do not have shortness of breath or atypical chest imaging

That said, mild cases can still have long-lasting effects. People who experience symptoms months after first contracting the virus — and after it is no longer detectable — are referred to as long haulers.

According to a 2021 study, approximately one-third of people with COVID-19 had persistent symptoms for as long as 9 months after infection.

That said, call emergency medical services if you or someone you care for has severe or life threatening symptoms such as difficulty breathing, chest pain, or confusion.

COVID-19 vs. flu

At the pandemic’s beginning, coronavirus caused more deaths than the seasonal flu.

However, a 2023 study by the Centers for Disease Control and Prevention (CDC) found that the outcomes for adults hospitalized with COVID-19 are similar to those hospitalized with the flu.

The only exception is COVID-19 patients from ages 18 to 49 years, the rate of death continues to be higher than the rate for the flu. The flu and COVID-19 also share many of the same symptoms.

Coronaviruses are zoonotic. This means they first develop in animals before being transmitted to humans. For the virus to be transmitted from animals to humans, a person has to come into close contact with an animal that has the infection.

There are 45 known coronaviruses, of which 8 are known to infect humans, including COVID-19. This also includes the common cold, which has been in human populations for so long that nowadays, its transmission is more common from one human to another.

Once the disease develops in people, the transmission of coronaviruses can occur from one person to another through respiratory droplets. This is a technical name for the wet stuff that moves through the air when you exhale, cough, sneeze, or talk.

The viruses hang out in these droplets. When you breathe, they get into your respiratory tract (windpipe and lungs), where the virus can then cause an infection.

SARS-CoV-2 can also form aerosols or dissolve into a fine spray of particles and moisture and remain suspended in the air for minutes to hours.

Researchers can’t definitively link COVID-19 to a cause even after five years of its emergence. It’s widely believed the transmission likely occurred in the open food market in Wuhan, China, although there are still theories about the virus originating in the laboratory.

In a 2024 report by the Global Catastrophic Risk Institute, 77% of surveyed experts believed the virus came from an animal naturally.

However, one out of five experts also believed there was a 21% probability that COVID-19 resulted from a “research-related accident.”

You’re at high risk for contracting SARS-CoV-2 if you come in contact with someone carrying the virus, especially if you get exposed to their saliva or if you were near them when they coughed, sneezed, or talked.

Without taking proper preventive measures, you’re also at high risk if you:

  • live with someone who has contracted the virus
  • are providing home care for someone who has contracted the virus
  • have an intimate partner who has contracted the virus

Older adults (ages 65 years and older), and people with certain health conditions have a higher chance of developing severe complications if they contract the virus. These health conditions include:

The CDC also reports that pregnant people are more likely to experience severe COVID-19 illness than nonpregnant people.

Transmission of coronavirus to the fetus during pregnancy isn’t likely, but the newborn can contract the virus after birth.

However, according to a 2021 study, the antibodies in women who received vaccination were found in cord blood, meaning the antibodies are transferred to the baby, and they also can be found in breast milk.

The diagnosis of COVID-19 can be similar to other conditions that viruses cause using a blood, saliva, or tissue sample.

However, most tests use a cotton swab to retrieve a sample from the inside of your nostrils.

Locations that conduct tests include:

  • the CDC
  • some state health departments
  • commercial companies
  • certain pharmacies
  • clinics and hospitals
  • emergency rooms
  • community testing centers

Visit the website of your state’s health department or the U.S. Department of Health & Human Services to find testing centers near you.

At-home tests

At-home over-the-counter COVID-19 tests are available to test whether you currently have an active infection.

The Food and Drug Administration (FDA)has authorized these tests. You can buy them online and at most pharmacies and test them at home without a prescription. If you get a negative result, you may take a retest just in case of a false negative result.

Since it’s common to store these tests at home nowadays, it’s important that you check the expiration date before testing.

There’s currently no cure for COVID-19. Over the years, the FDA approved and deauthorized various treatments, such as monoclonal antibody medications, for example.

On November 30, 2022, the Food and Drug Administration (FDA) deauthorized bebtelovimab for emergency use in the United States. This was the last monoclonal antibody drug authorized by the FDA to treat COVID-19. The FDA made this decision because they did not expect it to neutralize new Omicron subvariants. These days, monoclonal antibody drugs aren’t as likely to be effective against newer variants and subvariants of the virus.

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The most current, approved medications for COVID-19, according to the CDC, are antiviral medications. These are:

  • Nirmatrelvir with Ritonavir (Paxlovid), a pill approved for adults and children ages 12 years and older
  • Remdesivir (Veklury), an IV infusion injection approved for adults and children
  • Molnupiravir (Lagevrio), a pill approved only for adults

Depending on your symptoms and their severity, if you are hospitalized for COVID-19, you may also get treatment, which includes:

The rate of death from COVID-19 has decreased significantly in recent years. These days, more than 80% of all COVID-19 infections are mild, and many people have had the virus more than once.

That said, the most serious complication of COVID-19 is still a gradual or abrupt decline in health, resulting in acute respiratory failure and acute respiratory distress syndrome (ARDS), or multiple organ failure that ultimately leads to death.

One study reports that ARDS occurred in up to 32.2% of cases, while other studies mentioned ARDS only happening in 3.6% of patients. That said, according to another 2023 study involving 4,700 patients who experienced organ failure due to the virus, 5.8% or 272 patients died as a result.

The most common type of organ failure was respiratory system dysfunction, followed by problems with the heart, the central nervous system, the gastrointestinal system, and the kidneys.

Other possible complications include:

The best way to prevent the transmission of coronaviruses is to avoid or limit contact with people who are showing symptoms of COVID-19 or any respiratory infection.

The next best thing you can do is practice good hygiene and physical distancing to help prevent bacteria and viruses from being transmitted.

Prevention tips

  • Wash your hands frequently for at least 20 seconds at a time with warm water and soap. How long is 20 seconds? About as long as it takes to sing your “ABCs.”
  • Do not touch your face, eyes, nose, or mouth when your hands are dirty.
  • Do not go out if you feel sick or have any cold or flu symptoms.
  • Stay at least 6 feet (ft) or 2 meters (m) away from people. Avoid crowds and large gatherings.
  • Cover your mouth with a tissue or the inside of your elbow whenever you sneeze or cough. Throw away any tissues you use right away.
  • Wear a mask or face covering in public places.
  • Clean any objects you touch a lot. Use disinfectants on objects like phones, computers, and doorknobs. Use soap and water for objects that you cook or eat with, like utensils and dishware.

While keeping a distance and wearing a mask are no longer required, they are still recommended for optimal prevention.

If you choose to wear a mask, wash it after each use. Avoid touching the front of it with your hands. Also, try to avoid touching your mouth, nose, and eyes when you remove it. This helps prevent you from possibly transferring the virus from a mask to your hands and from your hands to your face.

Certain people should not wear face masks, including:

  • children under 2 years of age
  • people who have difficulty breathing
  • people who are unable to remove their own masks
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Vaccines

On December 11, 2020, the FDA granted its first EUA for a vaccine. Since then, newer versions and booster shots, have been developed.

The vaccines available currently are manufactured by Pfizer-BioNTech, Moderna, and Novavax. Healthcare professionals highly recommend them to protect you against severe illness from the virus.

The CDC advises that everyone above 5 years of age get at least one dose. Younger children, older adults (65 years and older), and people with compromised immune systems or certain underlying medical conditions may need more than one dose for optimal effectiveness. This also includes a booster shot when an updated version is released.

Learn more: Who’s eligible for a COVID-19 booster?

Can I go out if I have COVID-19?

CDC advises you to stay at home if you test positive for any respiratory virus, including COVID-19, and avoid contact with others for at least 24 hours after your symptoms have reduced and you no longer have a fever (without the use of medication).

How long can you transmit COVID-19, if you contract it?

If you have COVID-19, you can transmit the virus to other people before and after showing symptoms. This occurs within 1 to 2 days before symptoms appear and in the first 8 to 10 days after. Even if you don’t have symptoms but test positive, you can still transmit the virus to others.

How long does COVID last?

Typically, symptoms will appear within 5 to 6 days of exposure and can persist between 1 and 14 days. Those who develop long covid may experience long-term symptoms for weeks, months, and sometimes years.

COVID-19, caused by the virus SARS-CoV-2, is a highly transmissible respiratory illness. Though it can range from mild to severe, most people experience mild symptoms and recover without complications.

While there is no known cure for COVID-19, treatments are available to help reduce symptoms and support breathing. Vaccines have helped to reduce the severity of illness for many people.

However, some people, including but not limited to young children, older adults, and people with compromised immune systems, can still develop severe illness. For this reason, it’s important to keep your distance from people while you have coronavirus infection, even if you don’t have symptoms.