COVID-19: Prevention, Treatment and Vaccines

What is COVID-19?

COVID-19, the coronavirus disease is caused by a virus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronaviruses are a large group of different viruses that may also cause the common cold, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

COVID-19 is a contagious airborne virus that can spread quickly within a home or community in spaces that are crowded and not well-ventilated. It most often causes symptoms in the lungs and respiratory tract and may resemble a cold, the flu or pneumonia.

Coughing, runny or stuffy nose, sore throat and fatigue commonly occur in mild cases, but a wide range of symptoms may occur. Some people have mild or no symptoms, while others can develop a severe illness that can lead to death. More recent variants have resulted in more upper respiratory symptoms similar to a cold, but high risk people can still be at risk of severe symptoms or death. Some people have also developed long-term symptoms after initial illness often referred to as “Long COVID”. 

Vaccination, as recommended by health authorities, can help to protect people from severe illness, hospitalization and death due to COVID-19. Reformulated, annual fall vaccines have been approved or authorized by the FDA to target more recent variants of the Omicron family strain.

When did COVID-19 start?

The COVID-19 outbreak began in Wuhan, China in late 2019 and rapidly spread around the world. The virus caused a global pandemic in March 2020, as declared by the World Health Organization (WHO).

Most people in the U.S. or world had never gone through a pandemic of the magnitude of COVID-19. Initially, no vaccine or treatment was available. Safety measures were instituted in many countries, including: wearing a mask in public, lockdowns to help prevent viral spread, work and school from home, and gathering outside became the norm. Today, some of these social distancing practices still exist, even though the magnitude of the virus has subsided.

Over 7.1 million people have died from COVID-19 globally, with close to 1.2 million in the US, as of June 2025, according to WHO. Note: These numbers are subject to change based on official reporting to WHO.

What caused the spread of COVID-19?

A virus called SARS-CoV-2 causes COVID-19 disease. COVID-19 is a respiratory disease and is spread from person to person.

You can catch the virus from breathing in particles from other people that contain the virus. These people may be coughing, sneezing, talking, singing and even just breathing in your area. Enclosed, unventilated spaces can increase your risk of breathing in the virus.

COVID-19 is very contagious, including the most recent variants. People can spread the virus even if they do not know they are infected or have any symptoms. The virus can begin spreading 2 to 3 days before any symptoms start.

In some circumstances, droplets that contain the virus can contaminate a surface that you may touch, but it is not common to get ill in this manner.

COVID-19 may spread from animals to people in some situations, but the risk is low. Pet cats and dogs can sometimes become infected by close contact with people who have COVID-19. If you have tested positive for COVID-19, you should avoid contact with your pet. This includes petting, snuggling, kissing, licking, sharing food, and sleeping in the same bed.

What is the most recent variant of COVID-19?

As of May 2025, the top 5 variants (with estimated percentages), circulating in the U.S. are all lineages of the Omicron variant and include:

• LP.8.1 (73%)
• XFC (10%)
• XEC (4%)
• LF.7.7.2 (3%)
• LF.7 (2%)

The most dominant variant, LP.8.1, originates from the the JN.1 variant line (of Omicron lineage). These estimates are reported by the CDC on the COVID Data Tracker.

The virus changed into several different forms (call variants), like Delta and Omicron, since the original virus was found.  The variants may lead to a more or less severe form of the disease. New variants can form in one part of the world and spread rapidly to other areas. The immunity of the population and the specific changes in the virus can help to predict how severe a new variant may be.

The latest Omicron family variants have developed changes to the spike protein that may allow the virus to bypass effect from former vaccines. Upper respiratory tract symptoms (runny nose, sore throat, headache) are common but older or immunocompromised patients may be at risk for more severe lung infections, hospitalization or death.

New or reformulated COVID-19 vaccines will be developed and offered each year in the U.S, based on circulating variants, similar to how the influenza vaccine is made annually.

What symptoms do you have with COVID-19?

People with COVID-19 may have a wide range of symptoms. The first symptoms of COVID-19 may not appear for several days up to 2 weeks after you are infected. Some people have very severe symptoms, while others have more mild symptoms or no symptoms at all.

The most common symptoms of COVID-19 include:

• fever, chills or shivering
• cough
• shortness of breath or difficulty breathing
• fatigue (physically and mentally tired)
• muscle pain or body aches
• headache
• confusion
• changes or loss of taste or smell
• sore throat
• stuffy or runny nose, nasal congestion
• nausea or vomiting
• diarrhea
• chest pain / chest pressure.

This list does not include all possible symptoms of COVID-19.

Who is at risk for severe COVID-19 disease?

Older adults and the elderly (65 years of age and older) are at very high risk from severe illness due to COVID-19. Others at high risk include people with:

• chronic or long-term health conditions like serious heart disease
• kidney disease
• type 1 or type 2 diabetes
• lung conditions like chronic obstructive pulmonary disease (COPD) and possibly asthma
• sickle cell disease
• cystic fibrosis
• obesity
• weak immune systems (immunosuppressed)
• nursing home residents
• obesity
• pregnancy

Additional conditions may put people at high risk. Check with your heath care provider if you have a chronic illness.

Which symptoms need emergency treatment for COVID-19?

Call 911 right away if you or someone with COVID-19 shows these symptoms, and tell the operator the symptoms are from someone with, or suspected of having, COVID:

• trouble breathing
• persistent pain or pressure in the chest
• new confusion
• inability to wake or stay awake
• pale, gray, or blue-colored skin, lips, or nail beds, depending on skin tone

You can also contact your closest emergency treatment facility and tell them that you need emergency care for someone who may have COVID-19.

How is COVID-19 diagnosed?

There are 2 main tests used to determine if you have COVID-19: molecular tests and antigen tests. To test, a swab is needed from the inside of your nose or mouth. If you think you have been exposed to COVID, get tested at either your doctor’s office, the pharmacy, or using an at-home testing kit.

• Polymerase chain reaction (PCR) tests (molecular tests): These are the “gold standard” and most accurate tests for COVID. These tests identify genetic parts of the virus that cause COVID. They can be performed at your doctor’s office or the pharmacy and sent to a lab. Some home tests exist that can be mailed to a lab. Your results usually take 1 to 3 days, but this is variable. These tests are more reliable than at home testing kits.
• Antigen tests: These tests give results rapidly, usually in 15 minutes, and can be used at home. Antigen tests look for virus proteins but are not as accurate as PCR tests. You may get a false positive, especially early in infection or if no symptoms are present. The FDA recommends 2 negative antigen tests for people with symptoms, or 3 negative antigen tests for people without symptoms, taken 48 hours apart. Instead, a single PCR test can be used to confirm an antigen test result. Common antigens tests include the Abbott BiNaxNOW, iHealth, and On/Go COVID-19. 

Antibody tests are primarily used to determine if you had a recent or past infection with COVID-19. It is not used as a diagnostic test or to show if you are immune to the disease. A blood sample is used for this test. Antibody tests are infrequently used today.

Imaging tests, such as CT, MRI, ultrasound or x-ray may be used to help identify complications like a blood clot, pneumonia, or a lung infection.

What if I test positive for COVID-19?

Contact your healthcare provider right away if you test positive for COVID-19. They can help determine which treatments are best for you based on your age, symptoms, risk factors and health history.

Some COVID treatments need to be started as soon as possible and within 5 or 7 days of symptoms onset, and other treatments are only used in the hospital and if you need breathing support, such as oxygen or mechanical ventilation. Do not delay contacting your doctor.

In more severe cases, other treatments, such as blood thinners, additional oxygen or a ventilator may be needed.

COVID-19 treatments are still under research in clinical trials. Treatments continue to evolve, especially as new variants emerge.

The FDA has not approved or authorized the use of ivermectin to prevent or treat COVID-19 and caution the public about the potential risks. Ivermectin should only be used in patients for COVID-19 treatment in a research setting, as part of a clinical trial.

Select treatments approved by the FDA for COVID-19

• Actemra (tocilizumab) - an intravenous (IV) or subcutaneous (injected under the skin) immune modulator approved for hospitalized adults with COVID-19 who are receiving systemic corticosteroids (for example: dexamethasone) and require supplemental oxygen, mechanical ventilation, or extracorporeal membrane oxygenation (ECMO). Actrema was FDA approved to treat COVID-19 on December 21, 2022, for specific adult patients. Pediatric patients (aged 2 years to 18 years) with COVID-19 also have access to Actrema under emergency use authorization (EUA).
• Olumiant (baricitinib) - an oral immune modulator for the treatment of COVID-19 in hospitalized adults requiring supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO). When used to treat COVID-19, Olumiant is associated with an improvement in COVID-19 symptoms and a reduced need for ventilators. While generally well-tolerated, some patients developed elevated liver enzymes as a side effect. 
• Paxlovid (nirmatrelvir / ritonavir; co-packaged) - NDA approved on May 25, 2023 as an oral antiviral treatment for the treatment of mild-to-moderate coronavirus disease 2019 (COVID-19) in adults who are at high risk for progression to severe COVID-19, including hospitalization or death. Paxlovid is not approved for use as pre-exposure or post-exposure prophylaxis for prevention of COVID-19. A full drug interaction review should be completed prior to treatment. Pharmacists and other licensed health care providers can prescribe Paxlovid to eligible patients, with certain health records.
• Veklury (remdesivir) - an intravenous (IV) therapy approved for patients in the hospital or in an outpatient setting. Approved for adults and children (who are at least 28 days of age and older who weigh at least 7 pounds [3.1 kg]) who are in the hospital; or who are not in the hospital but have mild-to-moderate COVID-19 and are at high risk for progression to severe COVID-19, including hospitalization or death. It is not known if this medicine is safe and effective in children under 28 days of age or weighing less than 7 pounds (3 kg).

Select treatments authorized for COVID-19 under FDA’s Emergency Use Authorization (EUA)

Emergency use authorization (EUA) for COVID-19 is not the same as FDA approval. Emergency use authorization is when the FDA allows unapproved drugs or unapproved uses of approved drugs, under certain conditions. The following treatments have not been approved by the FDA to treat COVID-19.

• Actemra (tocilizumab) - an intravenously / subcutaneously injected immune modulator for hospitalized children aged 2 years to under 18 years with COVID-19 who are receiving systemic corticosteroids and require supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO).
• Gohibic (vilobelimab) - an intravenous infusion immune modulator authorized to treat COVID-19 in hospitalized adults when started within 48 hours of receiving invasive mechanical ventilation (IMV) or extracorporeal membrane oxygenation (ECMO - a heart-lung machine that helps increase oxygen in the blood).
• Kineret (anakinra) - an immune modulator authorized for the treatment of COVID-19 in hospitalized adults with pneumonia requiring supplemental oxygen (low- or high-flow oxygen) who are at risk of progressing to severe respiratory failure and likely to have an elevated plasma soluble urokinase plasminogen activator receptor (suPAR) that may be a sign of increased risk of worsening of the disease.
• Lagevrio (molnupiravir) - an oral antiviral authorized by the FDA for emergency use for the treatment of mild-to-moderate COVID-19 in people 18 years of age and older who are at high risk for progression to severe COVID-19, including hospitalization or death; and for whom other COVID-19 treatment options (authorized or approved) are not available or applicable. 
• Olumiant (baricitinib) - an oral immune modulator authorized for emergency use of COVID-19 in hospitalized children 2 to less than 18 years of age requiring supplemental oxygen, invasive mechanical ventilation, or extracorporeal membrane oxygen (ECMO). 
• Paxlovid (nirmatrelvir / ritonavir; co-packaged) - Paxlovid is authorized for the treatment of mild-to-moderate COVID-19 in pediatric patients (12 years of age and older weighing at least 40 kg) who are at high risk for progression to severe COVID-19, including hospitalization or death.
• Pemgarda (pemivibart) is a SARS-CoV-2 spike protein-directed attachment inhibitor (monoclonal antibody) authorized under EUA for the pre-exposure prophylaxis of COVID-19 in adults and adolescents (12 years of age and older weighing at least 40 kg) who are not currently infected with SARS-CoV-2 and had no known recent exposure to an individual infected with SARS-CoV-2; AND who have moderate-to-severe immune compromise due to a medical condition or receipt of immunosuppressive medications or treatments and are unlikely to mount an adequate immune response to COVID-19 vaccination.
• The FDA currently only authorizes the use of convalescent plasma to treat people (in either the outpatient or inpatient setting) with compromised immune systems (with immunosuppressive disease or receiving immunosuppressive treatment) who have COVID-19. The convalescent plasma must have high levels (titer) of antibodies. This treatment was also approved on Jan 13, 2025 for OneBlood, a not-for-profit blood center serving the southeastern United States.

Anti-inflammatory corticosteroids like dexamethasone may also be used in severely ill, hospitalized patients with COVID-19 who are on supplemental oxygen or ventilatory support. This treatment has been shown to improve clinical outcomes and reduce death. There are no data to support the use of systemic corticosteroids in non-hospitalized patients with COVID-19.

For questions about symptomatic treatment, contact your doctor. Other treatments may be used to help relieve common symptoms of COVID-19, such as headache, muscle aches, fever, cough and congestion. This usually includes over-the-counter (OTC) medicines like decongestants, cough suppressants, sore throat lozenges or sprays, and pain and fever relievers like acetaminophen (Tylenol) or NSAIDs. Follow all OTC directions on the Drug Facts label found on the product. 

How do I prevent COVID-19?

Vaccination is the single best way to prevent infection, even if you’ve previously had COVID-19 disease. Vaccination is recommended by the CDC for everyone 6 months of age and older and can lower the risk of severe disease or death. Vaccination can also help protect other people around you, including those who are at high risk for severe illness.

Vaccines are available at most pharmacies in the U.S. or from your healthcare provider. Check with your insurance carrier or pharmacist to determine coverage. To find an updated COVID-19 vaccine near you, visit the CDC website at vaccines.gov.

Other ways to help prevent infection with the virus include:

• staying away from sick people when possible
• follow the local social distancing guidelines
• wear a face mask when needed (crowded indoor spaces, airplanes, other public transit)
• wash your hands (at least 2 minutes with soap and water) or use alcohol gel (at least 60% alcohol) to clean hands when needed
• cover your mouth if sneezing or coughing
• avoid touching your eyes, nose, and mouth

Available COVID Vaccines: 2025-2026

There are several COVID-19 vaccines available in the U.S (as of May 2025) made by either Pfizer and BioNTech, Moderna or Novavax. New vaccines for the 2025-2026 season include mNEXSPIKE and Nuvaxovid.

Pfizer and BioNTech - mRNA vaccines. Comirnaty is the brand name of the COVID-19 vaccine made by Pfizer and BioNTech which is approved for adults and adolescents 12 years and older. The Pfizer-BioNTech COVID-19 vaccine has Emergency Use Authorization (EUA) for children aged 6 months through 11 years.

Moderna - mRNA vaccines. Spikevax is the brand name of the COVID-19 vaccine made by Moderna which is approved for use in adults and adolescents aged 12 years and older. The Moderna COVID-19 vaccine has Emergency Use Authorization (EUA) for children aged 6 months through 11 years.

• On May 30, 2025, the FDA approved mNEXSPIKE vaccine to prevent COVID-19 in individuals who have been previously vaccinated with any COVID-19 vaccine and who are 65 years of age and older, OR 12 years through 64 years of age with at least one underlying condition that puts them at high risk for severe outcomes from COVID-19.
• Moderna expects to have mNEXSPIKE available for the 2025-2026 U.S. respiratory virus season.

Novavax - protein adjuvant (non-mRNA vaccine). The Novavax COVID-19 vaccine is a protein subunit vaccine that may be used to help the body form immunity to SARS-CoV-2, the virus that causes COVID-19. It can be used in adults and children 12 years of age and older. Novavax is available for use under the FDA's Emergency Use Authorization (EUA). It is not authorized for use in children younger than 12 years of age.

• On May 19, 2025, the FDA approved Nuvaxovid (COVID-19 Vaccine, Adjuvanted), a protein-based, non-MRNA vaccine for active immunization to prevent coronavirus disease 2019 (COVID-19) in adults 65 years and older, and for individuals 12 through 64 years who have at least one underlying condition that puts them at high risk for severe outcomes from COVID-19.
• Nuvaxovid is an updated version of the Novavax COVID-19 Vaccine formulated to target the JN.1 variant. Novavax expects to have Nuvaxovid available for the 2025-2026 U.S. respiratory virus season.

These vaccines do not contain SARS-CoV-2, the virus that causes COVID-19 and cannot give you COVID-19 and will not treat an active COVID-19 infection.

Like any vaccine, these vaccines may not protect every person but can help prevent severe illness, hospitalization and death.

How many COVID vaccine doses do I need?

The number of doses you need depends upon your age, vaccine history and health. Discuss with your healthcare provider how many vaccines you or your child may need. COVID-19 vaccines developed by Moderna, Pfizer BioNTech and Novavax are now approved or authorized by the FDA.

Although vaccine protection declines over time, repeat vaccination as recommended by your healthcare provider can help to rebuild immunity towards the latest variants. 

Side effects of COVID-19 vaccines

Side effects can occur with COVID-19 vaccines but are typically mild to moderate and short-lived over a day or two. Some people do not have any side effects. You cannot get COVID-19 infection from the vaccine. 

• Side effects may include: local pain at the injection site, fever, chills, feeling tired or fatigued, muscle aches and pains, and headache. Severe side effects, like allergies or  inflammation of the heart muscle (myocarditis) are rare.
• Over-the-counter (OTC) pain relievers and fever reducers like acetaminophen (Tylenol) or NSAIDs (ibuprofen, naproxen) can usually be used to treat side effects after receiving the vaccine.
• It is not recommended to use acetaminophen NSAIDs before vaccination to try to prevent any side effects as it’s not known if this would interfere with your immune response. 

Serious side effects, like severe allergies (anaphylaxis) may occur.

Inflammation of the heart muscle (myocarditis) and inflammation of the lining outside the heart (pericarditis) have occurred but are rare. Symptoms usually have started within a few days to 2 weeks following vaccination. These heart side effects are rare and most often occur in teens or younger adult males (ages 12 to 24 years). It is usually a mild side effect that is treatable. Seek medical attention right away if you or your child develops chest pain, shortness of breath or difficulty breathing, or feelings of having a fast-beating, fluttering, or pounding heart after receiving a COVID-19 vaccine.

Tell your healthcare provider if you’ve had a previous severe reaction to any vaccine or have a history of myocarditis or pericarditis.

What should I know about long COVID?

Some people who have been infected with COVID-19 can experience long-term effects from their infection, known as Long COVID, Post-COVID Conditions (PCC), or post-acute sequelae of SARS-CoV-2 (PASC).

Symptoms are considered Long COVID if they begin or continue at least 4 weeks after the initial infection. Often, people who develop long COVID have been critically ill initially with acute COVID-19.

Experts think long COVID-19 may occur because the immune system may overreact to the virus, attacking healthy parts of the body instead of just the virus (like organs, nerves and blood vessels nerves). It’s not known how long it may last in any one patient. In general, it may continue for weeks, months or even years.

There is no test or lab work that determines if you have Long COVID-19. Your doctor will assess your health history and examination. In addition, there is no specific treatment that will cure Long COVID, but your doctor will treat the symptoms and offer advice on managing your illness.

Risk factors for Long COVID

You may be at greater risk for Long COVID if you:

• are 65 years of age or older
• are a current or former smoker
• have a weak immune system
• have obesity
• have diabetes
• have kidney, heart, or lung disease
• are not vaccinated against COVID-19
• have had multiple COVID-19 infections

What are the symptoms of long COVID-19?

Symptoms can be different for different people, but may include:

• fatigue, extreme tiredness
• trouble with breathing
• trouble sleeping
• chest pain
• coughing
• headache
• trouble thinking or focusing (“brain fog”)
• memory problems
• joint, nerve or muscle pain
• stomach problems like diarrhea
• loss of appetite
• loss of, or reduced sense of smell or taste

Note: This is not a complete list of symptoms of Long COVID.

Symptoms may eventually go away completely with Long COVID, or some symptoms, like feeling tired or trouble thinking (brain fog), may continue.

More serious side effects can include blood clots, severe shortness of breath, and lung infections. Severe inflammation may occur in the organs (heart, digestive tract, skin, brain) in both adults and children and is called multi-symptom inflammatory syndrome.

Some people may also develop mental health disorders such as depression, anxiety or PTSD (post-traumatic stress disorder) and suicidal thoughts or actions.

In July 2021, Long COVID was added as a recognized condition that could result in a disability under the Americans with Disabilities Act (ADA).

Note: Information about COVID-19 disease, treatments and vaccines changes rapidly. You are encouraged to review the latest recommendations available online at the Centers for Disease Control & Prevention (CDC), the U.S. Food and Drug Administration (FDA), the World Health Organization (WHO), and with your local and state health authorities.

This is not all the information you need to know about COVID-19 or COVID-treatment for safe and effective use and does not take the place of your healthcare provider's directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.