COVID-19 and the SARS-CoV-2 coronavirus pandemic

COVID-19 is a contagious disease caused by the SARS-CoV-2 coronavirus, which led to a global pandemic starting in January 2020. Symptoms vary and can include fever, fatigue, cough, breathing difficulties, and loss of taste or smell. While approximately one-third of infected individuals do not develop noticeable symptoms, others experience a range of severity.

Most patients (81%) develop mild to moderate symptoms, such as mild pneumonia. However, 14% develop severe symptoms like hypoxia, and 5% face critical complications including respiratory failure or multiorgan dysfunction. Older populations are at a higher risk for severe illness. Some individuals suffer from long-term effects known as long COVID, which can involve organ damage lasting months or years.

Transmission occurs through infectious particles inhaled via the air or through contact with the eyes, nose, or mouth after touching contaminated surfaces. The risk is elevated in close proximity or indoors where airborne particles can remain suspended. Individuals can remain contagious for up to 20 days, even without symptoms.