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. 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 vaccines were approved or authorized by the FDA in the fall of 2023 to target more recent Omicron variants.

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 1.1 million people have died from COVID-19 in the U.S., and close to 7 million worldwide, as of November 2023, according 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. 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?

The virus has changed into several different forms (call variants), like Delta and Omicron, since the original virus was found. The latest variants in the U.S. as of October 2023 are the HV.1 and EG.5 variants, both Omicron subvariants. Research shows HV.1 was responsible for about 25% of cases and EG.5 for 22% of cases as of October 2023, more than any other SARS-CoV-2 variant at that time. Another variant called FL 1.5.1 was rapidly spreading (13% of cases) as well as other XBB and Omicron subvariants.

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 offshoots like EG.5 do not appear to lead to more severe disease but do appear to be more contagious than earlier variants. However, EG.5 does appear to have a change to its spike protein that may allow it to bypass acquired immunity from former vaccinations or infection. Upper respiratory tract symptoms (runny nose, sore throat) are common but older or immunocompromised patients may be at risk for more severe lung infections.

Pfizer, Moderna, and Novavax have all developed updated COVID-19 vaccines for the fall of 2023. While not an exact match, the new fall 2023 mRNA vaccines, originally designed to cover the Omicron variant XBB 1.5, should help cover other variants, like the EG.5 and FL 1.5.1 subvariants, as well. The oral antiviral Paxlovid and the at-home COVID tests are also expected to work for the latest Omicron variants.

Experts anticipate new vaccines will be developed and offered each year based on circulating variants, similar to how the flu 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

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.

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. 

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

What treatments are available for COVID-19?

There are several FDA approved treatments for COVID-19, as well as medicines authorized for emergency use.

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.

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 intravenously / subcutaneously injected 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).
• Olumiant (baricitinib) - an oral immune modulator for the treatment of COVID-19 in hospitalized adults requiring supplemental oxygen, mechanical ventilation, or extracorporeal membrane oxygenation (ECMO).
• Paxlovid (nirmatrelvir / ritonavir; co-packaged) - NDA approved on May 25, 2023 as an oral antiviral treatment for certain adults. It is used for the treatment of mild to moderate 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. Pfizer will assume responsibility for distribution of this treatment after December 15, 2023, when the U.S. government fully transitions out of distribution. As of March 9, 2024, the presentation of Paxlovid in EUA packaging may not be dispensed.
• Veklury (remdesiver) - an intravenous (IV) therapy approved for patients in the hospital or in an outpatient setting. Approved for adults and children (28 days of age and older and weighing at least 3 kilograms) with mild to moderate COVID-19, at high risk for severe COVID-19, including hospitalization or death.

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

• 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 initiated within 48 hours of receiving invasive mechanical ventilation (IMV) or extracorporeal membrane oxygenation (ECMO).
• Kineret (anakinra) - is an immune modulator authorized for the treatment of COVID-19 in hospitalized adults with pneumonia requiring supplemental oxygen who are at risk of progressing to severe respiratory failure and likely to have an elevated plasma soluble urokinase plasminogen activator receptor (suPAR).
• Lagevrio (molnupiravir) - an oral antiviral authorized emergency use of molnupiravir 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 are not available or applicable. Some clinicians do not recommend this treatment, especially if Paxlovid is available.
• Olumiant (baricitinib) - an oral immune modulator authorized for use in 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 certain adults and 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. On November 1, 2023, the FDA revised the EUA for Paxlovid in children 12 to under 18 years to authorize use of NDA labeled Paxlovid for the treatment of mild-to-moderate COVID-19. As of March 9, 2024, the presentation of Paxlovid in EUA packaging may not be dispensed.
• Pemgarda (pemivibart) is a SARS-CoV-2 spike protein-directed attachment inhibitor 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 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.

Due to the high frequency of variants circulating within the U.S. that are not susceptible monoclonal antibodies (mAbs), the products below are NOT currently authorized until further notice by FDA. They may not be administered for the pre-exposure prophylaxis for prevention or the treatment of COVID-19 under the EUA.

• REGEN-COV (casirivimab and imdevimab)
• Sotrovimab
• Bamlanivimab and Etesevimab
• Bebtelovimab
• Evusheld (tixagevimab / cilgavimab; copackaged) - the NIH recommends against the use of tixagevimab + cilgavimab for preexposure prevention of COVID-19.

Convalescent plasma with high antibody levels is authorized by the FDA, and may also be used for outpatient treatment in immunocompromised adults who cannot receive vaccines. It is not widely available in the U.S.

Antiinflammatory 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 nonhospitalized patients with COVID-19.

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 NSAIDs or acetaminophen. Follow all OTC directions on the Drug Facts label found on the product.

How do I prevent COVID-19?

Getting the current and recommended vaccines is the best way to prevent 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.

As of October 2023, over 13 billion vaccine doses have been administered worldwide.

In the U.S. there are three new vaccines to choose from in fall 2023, all approved or authorized by the FDA. 

Newer monovalent vaccines targeting the SARS-CoV-2 omicron variant lineage XBB.1.5 (2023-2024 formula) include: 

• mRNA vaccines: All individuals aged six years and older may receive a monovalent mRNA COVID-19 vaccine (from either Pfizer or Moderna), if they have not already received one. These vaccines, approved and authorized on Sept. 11, 2023, have been found to be safe and protect against the Omicron variants. These vaccines are available for people 6 months of age and older.
• Novavax COVID-19 vaccine: The Novavax COVID-19 Vaccine, Adjuvanted vaccine was authorized by the FDA on Oct. 3, 2023. Individuals 12 years of age and older previously vaccinated with a COVID-19 vaccine (and who have not already been vaccinated with a recently updated mRNA COVID-19 vaccine) are eligible to receive one dose and unvaccinated individuals should receive two doses. An adjuvant is an ingredient used in some vaccines to help create a stronger immune response in people receiving the vaccine.

The initial monovalent and bivalent vaccines from Pfizer and Moderna, as well as the Novavax COVID-19 Vaccine, Adjuvanted (original monovalent) are no longer authorized for use by the FDA. In addition, the J&J / Janssen COVID-19 vaccine, a viral vector vaccine, is no longer available for use.

Vaccination is the single best way to prevent infection, even if you’ve previously had COVID-19 disease. 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

How many COVID vaccine doses do I need?

The number of doses you need depends upon your age, vaccine history and health. Ask your healthcare provider how many vaccines you or your child need.

For the fall 2023 vaccines, individuals 5 years of age and older regardless of previous vaccination are eligible to receive a single dose of an updated mRNA COVID-19 vaccine at least 2 months since the last dose of any COVID-19 vaccine.

Children aged 6 months to 5 years may need multiple doses of COVID-19 vaccine to be up to date depending on the number of doses they’ve previously received, their age and if they have a weakened immune system.

Although vaccine protection declines over time, repeat vaccination as recommended by health authorities can help to rebuild immunity towards the variants. New COVID-19 vaccines developed by Moderna and Pfizer BioNTech are now approved or authorized by the FDA. They became available in Sept of 2023 and target the more recent Omicron variant XBB 1.5 and other circulating subvariants, as well.

Novavax COVID-19, adjuvanted vaccines are now available for the 2023-2024 season. People 12 years of age and older previously vaccinated with a COVID-19 vaccine (and who have not already been vaccinated with a recently updated mRNA COVID-19 vaccine from Pfizer or Moderna) are eligible to receive one dose and unvaccinated individuals will receive two doses.

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) or inflammation of the heart muscle (myocarditis) are rare. All three available vaccines may cause myocarditis, an extremely rare side effect which most often occurs in teen or younger adult males (ages 12 to 39 years). It is usually a mild side effect that is treatable. Tell your healthcare provider if you’ve had a previous severe reaction to any vaccine or have a history of myocarditis.

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 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 online at the Centers for Disease Control & Prevention (CDC), the U.S. Food and Drug Administration (FDA), the World Health Organization (WHO), and 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 doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.