COVID-19

Coronavirus disease 2019 (COVID-19, also known as SARS-2) is a <a href="/facts/Contagious_disease/x63nX34T">contagious disease</a> caused by the <a href="/facts/Coronavirus/LvV5mvl9">coronavirus</a> <a href="/facts/SARS-CoV-2/DxF8rDc1">SARS-CoV-2</a>. In January 2020, the disease spread worldwide, resulting in the <a href="/facts/COVID-19_pandemic/0xTsh7Ut">COVID-19 pandemic</a>.
The <a href="/facts/Symptoms_of_COVID%E2%80%9119/qEoGEt3A">symptoms of COVID‑19</a> can vary but often include fever, fatigue, cough, <a href="/facts/Breathing_difficulties/1jBfFzxU">breathing difficulties</a>, <a href="/facts/Anosmia/1XxX2R0h">loss of smell</a>, and <a href="/facts/Ageusia/cjrQ0Eax">loss of taste</a>. Symptoms may begin one to fourteen days <a href="/facts/Incubation_period/cqSwpKPk">after exposure</a> to the virus. At least a third of people who are infected <a href="/facts/Asymptomatic/6ewHqlEU">do not develop noticeable symptoms</a>. Of those who develop symptoms noticeable enough to be classified as patients, most (81%) develop mild to moderate symptoms (up to mild <a href="/facts/Pneumonia/Jw0KquTA">pneumonia</a>), while 14% develop severe symptoms (<a href="/facts/Dyspnea/1jBfFzxU">dyspnea</a>, <a href="/facts/Hypoxia_(medical)/JWV04G89">hypoxia</a>, or more than 50% lung involvement on imaging), and 5% develop critical symptoms (<a href="/facts/Respiratory_failure/R3GcdkJ1">respiratory failure</a>, <a href="/facts/Shock_(circulatory)/aIKGDS0e">shock</a>, or <a href="/facts/Organ_dysfunction/h5YCohyQ">multiorgan dysfunction</a>). Older people have a higher risk of developing severe symptoms. Some complications result in death. Some people continue to experience a range of effects (<a href="/facts/Long_COVID/9YQdUEE2">long COVID</a>) for months or years after infection, and damage to organs has been observed. Multi-year studies on the long-term effects are ongoing.
<a href="/facts/Transmission_of_COVID-19/vIYgt3qG">COVID‑19 transmission</a> occurs when infectious particles are breathed in or come into contact with the eyes, nose, or mouth. The risk is highest when people are in close proximity, but small <a href="/facts/Airborne_transmission/hpm1oR83">airborne</a> particles containing the virus can remain suspended in the air and travel over longer distances, particularly indoors. Transmission can also occur when people touch their eyes, nose, or mouth after touching surfaces or objects that have been contaminated by the virus. People remain contagious for up to 20 days and can spread the virus even if they do not develop symptoms.
<a href="/facts/COVID-19_testing/kN3j6bC2">Testing methods for COVID-19</a> to detect the virus's <a href="/facts/Nucleic_acid/2tTgcI0v">nucleic acid</a> include real-time <a href="/facts/Reverse_transcription_polymerase_chain_reaction/fQGqXPyW">reverse transcription polymerase chain reaction</a> (RT‑PCR), <a href="/facts/Transcription-mediated_amplification/Kd3cVYUT">transcription-mediated amplification</a>, and <a href="/facts/Reverse_transcription_loop-mediated_isothermal_amplification/eN6DqWxq">reverse transcription loop-mediated isothermal amplification</a> (RT‑LAMP) from a <a href="/facts/Nasopharyngeal_swab/PfWV1ShL">nasopharyngeal swab</a>.
Several <a href="/facts/COVID-19_vaccine/obToxWTT">COVID-19 vaccines</a> have been approved and distributed in various countries, many of which have initiated <a href="/facts/Deployment_of_COVID-19_vaccines/e3sLl9wB">mass vaccination campaigns</a>. Other <a href="/facts/Pandemic_prevention/wvRq6uGK">preventive measures</a> include physical or <a href="/facts/Social_distancing/DFFUCCaU">social distancing</a>, <a href="/facts/Quarantine/LyQM2k6K">quarantining</a>, ventilation of indoor spaces, <a href="/facts/Face_masks_during_the_COVID-19_pandemic/u7qwlDwJ">use of face masks or coverings</a> in public, covering coughs and sneezes, <a href="/facts/Hand_washing/BTgUfoRo">hand washing</a>, and keeping unwashed hands away from the face. While <a href="/facts/COVID-19_drug_development/GjWwxptG">drugs have been developed</a> to inhibit the virus, the primary <a href="/facts/Treatment_and_management_of_COVID-19/al0Ddhl2">treatment</a> is still <a href="/facts/Symptomatic_treatment/zQlnUC9x">symptomatic</a>, managing the disease through <a href="/facts/Symptomatic_treatment/zQlnUC9x">supportive care</a>, <a href="/facts/Isolation_(health_care)/qDFIYSsW">isolation</a>, and <a href="/facts/Medical_research/lSVBFxDJ">experimental measures</a>.
The first known case was <a href="/facts/COVID-19_pandemic_in_Hubei/rTXaB87u">identified in Wuhan</a>, China, in December 2019. Most scientists believe that the SARS-CoV-2 virus entered into human populations through natural <a href="/facts/Zoonosis/uvEPgxJ4">zoonosis</a>, similar to the <a href="/facts/SARS-CoV-1/jXYCe6w5">SARS-CoV-1</a> and <a href="/facts/MERS-CoV/a5LDpoW8">MERS-CoV</a> outbreaks, and consistent with other pandemics in human history. Social and environmental factors including <a href="/facts/Climate_change/rEN4BDE7">climate change</a>, <a href="/facts/Environmental_degradation/MTI24T7B">natural ecosystem destruction</a> and <a href="/facts/Wildlife_trade_and_zoonoses/l837qj1r">wildlife trade</a> increased the likelihood of such <a href="/facts/Zoonosis/uvEPgxJ4">zoonotic spillover</a>.

COVID-19 open-in-new

COVID-19