Covid19

COVID-19, short for coronavirus disease 2019, is an infectious disease caused by the coronavirus SARS-CoV-2. It was first identified in December 2019 in Wuhan, China, and led to a global pandemic declared by the World Health Organization in March 2020. Transmission occurs primarily via respiratory droplets and aerosols when an infected person breathes, speaks, coughs, or sneezes. Transmission can also occur by touching contaminated surfaces and then touching the face, though this is less common. The clinical spectrum ranges from asymptomatic or mild upper respiratory illness to severe pneumonia and death. Common symptoms include fever, dry cough, fatigue, shortness of breath, and loss of taste or smell; severe illness is more likely in older adults and people with underlying conditions.

Diagnosis is based on molecular tests such as reverse transcription polymerase chain reaction (RT-PCR) and rapid antigen tests. Prevention relies on vaccination, wearing masks in appropriate settings, improving ventilation, hand hygiene, and avoiding crowded areas. Multiple vaccines have been developed and authorized for emergency use, and booster doses have been recommended to maintain protection, particularly against newer variants. Treatments for hospitalized patients include supportive care and, where appropriate, antivirals, corticosteroids, and monoclonal antibodies.

The disease has caused substantial morbidity and mortality and disrupted health systems, economies, and daily life. Variants of concern with increased transmissibility or immune evasion have emerged over time, prompting updates to vaccines and public health guidance. Global surveillance, vaccination campaigns, and public health measures continue to play complementary roles in managing COVID-19.