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Overview

What Is SARS-CoV-2?

SARS-CoV-2 is a coronavirus that can infect people. COVID-19 is the illness that infection with this virus can cause. Like other viruses, SARS-CoV-2 has continued to evolve, leading to different variants over time.

How It Spreads (Transmission)

How SARS-CoV-2 Spreads

People infected with SARS-CoV-2 can release infectious respiratory particles when they breathe, talk, cough, or sneeze. Transmission is more likely during close contact and in crowded or poorly ventilated indoor spaces, where people may share the same air.

  • People may spread the virus before symptoms appear, while they have symptoms, or even when they have no symptoms.
  • Close contact and shared indoor air can increase exposure risk, although contagiousness varies between people and over time.
  • Older adults and people with certain medical conditions or weakened immunity have a higher risk of severe COVID-19, not necessarily a higher chance of acquiring the virus.

Conditions It Can Cause

Conditions SARS-CoV-2 Can Cause

  • COVID-19 – the acute illness caused by SARS-CoV-2 infection.
  • Long COVID or post-COVID condition – persistent, recurrent, or new symptoms after the acute infection.
  • Multisystem inflammatory syndrome in children (MIS-C) – a rare inflammatory complication that can occur after infection in children and adolescents.
  • Multisystem inflammatory syndrome in adults (MIS-A) – a rare inflammatory complication that can occur after infection in adults.

Symptoms

SARS-CoV-2 Symptoms

SARS-CoV-2 infection may cause no symptoms. When symptoms occur, common examples include fever or chills, cough, sore throat, a runny or blocked nose, fatigue, headache, muscle aches, and changes in taste or smell.

Diagnosis

How SARS-CoV-2 Is Diagnosed

Current SARS-CoV-2 infection is detected mainly with a molecular nucleic acid amplification test (NAAT), such as PCR, or with an antigen test using a respiratory sample. Test choice, the type of sample, and when testing is performed can affect how results are interpreted.

Test typeWhat it detectsTypical role
Molecular NAAT/PCRSARS-CoV-2 genetic materialDetects current infection with high sensitivity, depending on timing and specimen.
Antigen testViral proteinsRapidly assesses current infection but may miss some infections, especially early or when viral levels are low.
Serology or antibody testAntibodies made in response to infection or vaccinationMay show prior immune exposure; it is not generally used alone to diagnose an active infection.

Prevention

SARS-CoV-2 Prevention

Vaccination

Vaccine guidance

Staying up to date with the currently recommended COVID-19 vaccine reduces the risk of severe illness and may reduce infection or transmission for a period. Protection and recommendations can change as the virus evolves, so follow local public-health guidance for eligibility and timing.

  • Improve indoor ventilation and avoid crowded, poorly ventilated spaces when community transmission is high.
  • Wear a well-fitting, high-quality mask in higher-risk settings, especially when protecting someone vulnerable.
  • Stay home and follow current local guidance when sick or when testing indicates infection.
  • Use testing when symptoms, a known exposure, or a healthcare recommendation makes it appropriate.
  • People at higher risk of severe illness should ask a healthcare professional about prevention and early-treatment planning.

Affected Body System/Organ

Body Systems SARS-CoV-2 Can Affect

  • Respiratory system – lungs and airways are the primary systems involved.
  • Cardiovascular system – the heart and blood vessels can be affected during or after infection.
  • Nervous system – the brain, nerves, and senses can be affected in some people.
  • Immune system – inflammatory and immune responses can affect multiple organs.
  • Gastrointestinal system – the digestive tract can be involved.
  • Musculoskeletal system – muscles and joints may be affected during or after illness.

Diseases & Conditions

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