Coronavirus disease 2019
COVID-19 is a contagious disease caused by severe acute respiratory syndrome coronavirus 2. The first case was identified in Wuhan, China, in December 2019. It has since spread worldwide, leading to an ongoing pandemic. Symptoms include fever, cough, fatigue, breathing difficulties, and loss of smell and taste. Around one in five infected individuals do not develop any symptoms.
About Coronavirus disease 2019 in brief
COVID-19 is a contagious disease caused by severe acute respiratory syndrome coronavirus 2. The first case was identified in Wuhan, China, in December 2019. It has since spread worldwide, leading to an ongoing pandemic. Symptoms include fever, cough, fatigue, breathing difficulties, and loss of smell and taste. Around one in five infected individuals do not develop any symptoms. People remain infectious for up to ten days in moderate cases, and two weeks in severe cases. Preventive measures include physical or social distancing, quarantining, ventilation of indoor spaces, covering coughs and sneezes, hand washing, and keeping unwashed hands away from the face. The use of face masks or coverings has been recommended in public settings to minimise the risk of transmissions. Several vaccines have been developed and various countries have initiated mass vaccination campaigns. Although work is underway to develop drugs that inhibit the virus, the primary treatment is currently symptomatic. During human-to-human transmission, an average of 1000 SARS-CoV-2 virions are thought to initiate a new infection. The closer people interact, the more likely they are to transmit the virus. The relative importance of the larger droplets and aerosols is not clear as November 2020, when the pandemic is expected to begin, will be the first year it has been seen in the UK and the U.S. It is not known to transmit between rooms over long distances such as air ducts. Airborne transmission is able to occur indoors, in high risk locations, such as in restaurants, choirs, nightclubs, gyms, offices, and religious venues, often when they are less crowded or ventilated.
It can also evaporate into the aerosols, which can then be inhaled by other people. People with the same infection may have different symptoms, and their symptoms may change over time. Some people develop acute respiratory distress syndrome (ARDS) ARDS can be precipitated by cytokine storms, multi-organ failure, septic shock, and blood clots. In people without prior ears, nose, and throat disorders, loss of taste combined with loss of sense of smell is associated with CO VID-19 with a specificity of 95%. Most people develop mild to moderate symptoms, while 14% develop severe symptoms and 5% of patients suffer critical symptoms. The virus spreads from person to person mainly through the respiratory route after an infected person coughs, sneezed, sings, talks or breathes. Other people are infected if the virus gets into their mouth, nose or eyes. The exact route of transmission is rarely proven conclusively, but infection mainly happens when people are near each other for long enough. The longer people interact with each other, the greater the chance they are likely to spread the virus to each other. The larger the transmission distance, the higher the chance of transmission of the disease. The more likely it is to involve aerosols and droplets.