COVID-19

COVID-19 is a respiratory illness caused by the SARS-CoV-2 coronavirus. It can range from very mild to life-threatening, and continues to circulate worldwide.

Table of Contents

Quick Facts

  • Cause: SARS-CoV-2 virus
  • ICD-10: U07.1
  • Spread: Respiratory droplets, aerosols
  • Vaccine: Available

Overview

COVID-19 first emerged in 2019 and rapidly became a global pandemic. Most cases today are mild, but the virus can still cause severe pneumonia, blood clots, and other complications, especially in older adults and people with underlying health conditions.

Symptoms

  • Fever or chills
  • Cough
  • Sore throat
  • Runny nose or congestion
  • Fatigue
  • Muscle or body aches
  • Headache
  • Loss of taste or smell (less common with newer variants)
  • Shortness of breath
  • Nausea, vomiting, or diarrhea

Emergency warning signs

  • Trouble breathing
  • Persistent chest pain or pressure
  • New confusion or inability to stay awake
  • Bluish lips or face

Diagnosis

  • Rapid antigen tests (home or in clinic)
  • PCR tests (more sensitive, performed in labs)
  • Imaging (chest X-ray, CT) in moderate or severe cases

Treatment

Mild illness

  • Rest and fluids
  • Acetaminophen or ibuprofen for fever and aches
  • Monitor symptoms for worsening

Higher-risk patients

Antiviral medications such as nirmatrelvir/ritonavir or remdesivir may be prescribed for people at higher risk of severe disease, ideally started within a few days of symptom onset.

Severe illness

Hospital care may include oxygen support, intravenous steroids (dexamethasone), immune-modulating therapies, and treatment of complications such as blood clots.

Prevention

  • Stay up to date on COVID-19 vaccinations
  • Wash hands; cover coughs and sneezes
  • Improve ventilation indoors
  • Wear a mask in higher-risk situations
  • Stay home and test when sick

When to See a Doctor

Contact your healthcare provider early if you are at high risk of severe disease (older age, immunocompromised, pregnant, or with chronic conditions) so antiviral treatment can be started promptly. Seek emergency care for the warning signs above.

Related Conditions

Flu (Influenza)

Another viral respiratory illness

 Pneumonia

Lung infection that can follow COVID-19

 Cough

A common symptom

 Fever

Frequent with COVID-19

Frequently Asked Questions

How long does COVID-19 last?

Most uncomplicated cases improve within 7–10 days, though cough and fatigue can linger for weeks. Some people develop long COVID with symptoms lasting months.

Can I still get COVID-19 if I'm vaccinated?

Yes — vaccination doesn't fully prevent infection but substantially reduces the risk of severe illness, hospitalization, and death.

What is long COVID?

Long COVID refers to symptoms — fatigue, brain fog, shortness of breath, palpitations, and more — that persist or develop for weeks to months after the initial infection. It can affect people who had mild as well as severe acute illness.

When should I take antiviral medication?

Antivirals work best when started within 5 days of symptoms in people at high risk for severe disease. Contact your doctor early if you test positive and have risk factors.

Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you are experiencing a medical emergency, call your local emergency number immediately.

References

  • Centers for Disease Control and Prevention. COVID-19 Information.
  • World Health Organization. Coronavirus disease (COVID-19).