COVID-19: Global disease overview and prevention measures

COVID-19 is a contagious illness caused by the SARS‑CoV‑2 virus, first spreading worldwide in January 2020. Common symptoms include fever, fatigue, cough, breathing difficulty, loss of smell and taste, with an incubation period of one to fourteen days. About 81 % of patients experience mild to moderate disease, 14 % develop severe respiratory issues, and roughly 5 % become critically ill, with higher risk for older individuals.

A substantial proportion of infected people remain asymptomatic, and many experience long‑COVID symptoms for months or longer, affecting various organs. The virus transmits through airborne particles, close contact, and contaminated surfaces, and individuals can stay contagious for up to twenty days, even without symptoms. Diagnostic methods include RT‑PCR, transcription‑mediated amplification, and RT‑LAMP tests from nasopharyngeal swabs. Vaccines have been approved and deployed in many nations, complemented by public‑health measures such as physical distancing, ventilation, mask‑wearing, hand hygiene, quarantine, and isolation.

These preventive strategies and ongoing research continue to shape the global response to the pandemic.