COVID-19

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• COVID-19 Symptoms
• Vaccines
• Testing
• Treatment

COVID-19 is a respiratory illness caused by infection with SARS-CoV-2, a strain of coronavirus named severe acute respiratory syndrome coronavirus 2. SARS CoV-2 was first identified in 2019 and spread quickly causing COVID-19 illness throughout the world. COVID-19 was declared a public health emergency in the United States on January 31, 2020. Since then, it has affected hundreds of millions of people around the world. The U.S. COVID-19 public emergency ended on May 11, 2023, as hospitalizations and deaths decreased in the US and worldwide; however, COVID-19 continues to cause serious illness.

The Centers for Disease Control and Prevention (CDC) provides strategies to protect yourself and prevent transmission of COVID-19 on its webpage How to Protect Yourself and Others.

Healthcare workers have an increased risk of infection with COVID-19. Preventing workplace transmission requires additional precautions. See CDC's Infection Control Guidance: SARS-CoV-2.

Coronaviruses are zoonotic in origin in that they are initially transmitted from animals to humans. Although its exact origin remains unknown, it is believed that SARS-CoV-2 may have originated in bats since its genetic composition and structure is most closely related to coronavirus sequences found in the genus Rhinolophus bats that live in the limestone caves of Southeast Asia.

Although some coronaviruses circulate in a seasonal pattern and cause mild infection (i.e., the common cold), two additional strains have emerged within the last two decades with serious outcomes for human health. The first coronavirus strain, known as SARS (Severe Acute Respiratory Syndrome), caused an outbreak in 30 countries in 2003-2004, infecting thousands, 11% of whom died. MERS-CoV (Middle East Respiratory Syndrome coronavirus) was identified in 2012, and as of 2024 has resulted in nearly 1,000 deaths. Transmission continues at very low levels in the Arabian Peninsula due to frequent contact with camels which are carriers of the virus.

Over time, SARS-CoV-2 continues to mutate and change just like influenza viruses. These adaptations, called variants, have allowed SARS-CoV-2 to evade human immune systems as people become infected and subsequently become immune to earlier variants. The result is that the virus changes form over time and spreads through human populations recurrently, in waves or by seasons.

COVID-19 Symptoms

Symptoms

COVID-19 may be asymptomatic or develop into flu-like symptoms 2-14 days after exposure that may be mild or severe. These include:

• Cough
• Fever or chills
• Shortness of breath or difficulty breathing
• Fatigue
• Muscle or body aches
• Headache
• New loss of taste or smell
• Sore throat
• Congestion or runny nose
• Nausea or vomiting

Illness may last for a few days or as long as two weeks and may be complicated by infections of the upper (sinuses, throat, middle ears) and lower (bronchioles, lungs) respiratory systems. As described for all respiratory illnesses, adults who are aged 65 and older and people with certain health conditions are at higher risk of complications from COVID-19.

Adults most impacted by COVID-19 complications include those:

• who have a weakened immune systems (from diseases such as AIDS or cancer).
• with chronic lung disease (cystic fibrosis, asthma, and chronic obstructive pulmonary disease (COPD).
• with disabilities including cerebral palsy, Down's Syndrome, attention deficit hyperactivity disorder (ADHD).
• with other chronic medical conditions, including but not limited to:
  • heart disease (e.g., congenital, coronary artery disease, and congestive heart failure),
  • diabetes mellitus and other metabolic disorders,
  • chronic kidney disease,
  • liver diseases and disorders (e.g., cirrhosis, fatty liver disease, autoimmune hepatitis),
  • brain and nervous system diseases and disorders (former strokes, dementia),
  • mood disorders and schizophrenia,
  • blood disorders and anemias(e.g., sickle cell, aplastic, pernicious, etc.), and
  • high body mass index (≥40)

Complications of Infection with COVID-19

All respiratory infections can be complicated by pneumonia, but for adults at risk, COVID-19 is often complicated by other life-threatening conditions, particularly for hospitalized patients. When the immune system overreacts to fighting infection, this may cause life-threatening inflammation of:

• the respiratory system (asthma attacks, acute respiratory distress, or failure).
• organs including the heart (myocarditis), brain (encephalitis), and muscle tissues (myositis, rhabdomyolysis).
• multiple organs at once (respiratory, kidney, liver, heart, etc.) causing their failure.
• internal and external parts of the body in rapid fashion called Multisystem Inflammatory Syndrome.

As described for influenza, these conditions may lead to a cascade of negative events including disseminated intravascular coagulation (DIC), followed by excessive bleeding and septic shock.

Long-term effects of COVID-19

The term "Long COVID" is described by CDC as "a chronic condition that occurs after SARS-CoV-2 infection and is present for at least 3 months." Long COVID symptoms may be the same or different than those of COVID-19 and can last weeks, months or years. Every time a person develops COVID-19, they are at risk for Long COVID. People who have Long COVID often experience extreme fatigue and may be more likely to develop new health conditions such as diabetes, heart conditions, blood clots, or neurological conditions compared with people who have not had COVID-19.

For more information, visit CDC's website: Long COVID Basics.

Vaccines

According to the CDC, COVID-19 vaccines may provide lasting protection against critical illness or death due to COVID-19, so staying up to date with COVID-19 vaccination may also protect against Long COVID.

Much like influenza, COVID-19 vaccines are formulated based on SARS-CoV-2 virus strain circulation. Since SARS-CoV-2 is a "new" virus, vaccination formulation and production changes as the virus evolves. The CDC provides vaccine recommendations and informs the public when a new COVID-19 formula or booster is released. Employers should promote COVID-19 vaccination for all workers, especially those with underlying and chronic health conditions and those over the age of 65. Workers who have recently had COVID-19 should consider delaying vaccination for 90 days.

For more information, see CDC's COVID-19 Vaccines.

Testing

COVID-19 testing is widely available in the United States. Workers who are experiencing symptoms of COVID-19 can take an over the counter COVID-19 test. This test detects specific proteins of the SARS-CoV-2 virus, called antigens. Your local or state public health agency may provide advice on the use of over the counter tests to correctly diagnose infection with SARS-CoV-2.

Most importantly, follow FDA advice and manufacturer's instructions on how to use and read the antigen test:

• If you have a positive result, you likely have COVID-19.
• If you have a negative result, and have symptoms, repeat the test after 48 hours.
• If you have a negative result with no symptoms and believe you have been exposed to COVID-19, repeat the test after 48 hours and if negative, repeat the test again after another 48 hours for a total of three tests.

The most accurate test for COVID-19 is a nucleic acid amplification test (NAAT). This type of test detects SARS-CoV-2 genetic material in upper or lower respiratory fluid. These can be performed at the point of care (doctor's offices, pharmacies, urgent care centers, etc.) or in commercial laboratories.

Another type of test is called an antibody test. Your health care provider may give you this test to determine whether you have had COVID-19 and whether you have developed an immune response from past illness or from COVID-19 vaccination. Note that antibody tests are not diagnostic, i.e., they cannot tell you if you are currently infected with COVID-19 and can only reveal whether you have had COVID-19 in the past.

If you test positive on any of these tests, you likely have COVID-19 and should follow CDC and your medical provider's recommendations.

Treatment

Some workers will have mild symptoms from COVID-19 that can be treated with over-the-counter medications. Workers over the age of 65 are more likely to be hospitalized with COVID-19, since most have underlying health conditions. Workers over 65 and others with underlying health conditions should contact their health care provider right away if they suspect they have COVID-19 or have tested positive for SARS-CoV-2 virus.

Antiviral treatments are available to persons with conditions that put them at risk for serious illness from COVID-19. To be most effective, these should be taken as soon as possible after symptoms of COVID-19 appear. Oral treatments that can be taken at home include Paxlovid™ and Lagevrio™ (molnupiravir). Patients who are hospitalized may receive an intravenous medication, Veklury® (remdesivir).