COVID-19 Pandemic: Symptoms, Transmission, Testing and Prevention

COVID-19 is a contagious disease caused by the SARS‑CoV‑2 virus, which began spreading globally in January 2020 and triggered a worldwide pandemic. Reported symptoms range from fever, fatigue, cough and loss of smell or taste to severe respiratory distress; about 81% of cases are mild, 14% develop severe illness and 5% become critical. A substantial proportion of infected individuals experience long‑COVID, with lingering health effects lasting months or years.

The virus spreads primarily through inhalation of airborne particles, especially indoors, and can also be transmitted via contact with contaminated surfaces. Infected persons may remain contagious for up to 20 days, even without symptoms. Diagnostic methods include real‑time RT‑PCR, transcription‑mediated amplification and RT‑LAMP tests on nasopharyngeal samples. Vaccines have been approved and are being administered worldwide, while public‑health measures such as physical distancing, mask usage, improved ventilation, quarantine and hand hygiene continue to curb transmission.