Coronavirus in the context of "Severe acute respiratory syndrome coronavirus 2"

Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a coronavirus that causes COVID-19, the respiratory illness responsible for the COVID-19 pandemic that began in late 2019. The virus previously had the provisional name 2019 novel coronavirus (2019-nCoV), and has also been called human coronavirus 2019 (HCoV-19 or hCoV-19). First identified in the city of Wuhan, Hubei, China, the World Health Organization designated the outbreak a public health emergency of international concern from January 30, 2020, to May 5, 2023. SARS‑CoV‑2 is a positive-sense single-stranded RNA virus that is contagious in humans.

SARS‑CoV‑2 is a virus of the species Betacoronavirus pandemicum (SARSr-CoV), as is SARS-CoV-1, the virus that caused the 2002–2004 SARS outbreak. Some animal-borne coronaviruses are more closely related to SARS-CoV-2 than SARS-CoV-1 is. The closest known relative is the BANAL-52 bat coronavirus. SARS-CoV-2 is of zoonotic origin; its close genetic similarity to bat coronaviruses suggests it emerged from such a bat-borne virus. Research is ongoing as to whether SARS‑CoV‑2 came directly from bats or indirectly through any intermediate hosts. The virus shows little genetic diversity, indicating that the spillover event introducing SARS‑CoV‑2 to humans is likely to have occurred in late 2019.

A COVID‑19 vaccine is a vaccine intended to provide acquired immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID‑19).

Knowledge about the structure and function of previous coronaviruses causing diseases like severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) accelerated the development of various vaccine platforms in early 2020. In 2020, the first COVID‑19 vaccines were developed and made available to the public through emergency authorizations and conditional approvals. However, immunity from the vaccines wanes over time, requiring people to get booster doses of the vaccine to maintain protection against COVID‑19.

The COVID-19 pandemic in China is part of the worldwide pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). China was the first country to experience an outbreak of the disease, the first to impose drastic measures in response (including lockdowns and face mask mandates), and one of the first countries to bring the outbreak under control.

The first wave of the disease manifested as the 2019–2020 COVID-19 outbreak in mainland China, beginning with a cluster of mysterious pneumonia cases, mostly related to the Huanan Seafood Market, in Wuhan, the capital of Hubei province. It was first reported to the local government on 27 December 2019, and published on 31 December. On 8 January 2020, a new coronavirus (SARS-CoV-2) was identified as the cause of the pneumonia by Chinese scientists. By 29 January, the virus was found to have spread to all provinces of mainland China. The virus was first confirmed to have spread to Hong Kong on 23 January 2020, thus originating the COVID-19 pandemic in Hong Kong. Confirmed cases were generally transferred to Princess Margaret Hospital's Infectious Disease Centre for isolation and centralized treatment. On 5 February, after a five-day strike by front-line medical workers, the Hong Kong government closed all but three border control points – Hong Kong International Airport, Shenzhen Bay Control Point, and Hong Kong–Zhuhai–Macau Bridge Control Point remaining open. The first case of the disease in Macau was confirmed on 22 January 2020, originating the COVID-19 pandemic in Macau. The city saw nine more cases by 4 February, but no more cases until 15 March, when imported cases began to appear. Until 26 April 2021, the city had 49 cumulative confirmed cases of COVID-19, all of those having recovered, and no deaths from the disease. Stringent government measures have included the 15-day closure of all 81 casinos in the territory in February; in addition, effective 25 March, the territory disallowed connecting flights at its airport as well as entry by all non-residents (with the exception of residents of mainland China, Hong Kong, and Taiwan), and from 6 April, the Hong Kong–Zhuhai–Macau Bridge was closed to public transport and most other traffic.

The common cold, or the cold, is a viral infectious disease of the upper respiratory tract that primarily affects the respiratory mucosa of the nose, throat, sinuses, and larynx. Signs and symptoms may appear in as little as two days after exposure to the virus. These may include coughing, sore throat, runny nose, sneezing, headache, fatigue, and fever. People usually recover in seven to ten days, but some symptoms may last up to three weeks. Occasionally, those with other health problems may develop pneumonia.

Well over 200 virus strains are implicated in causing the common cold, with rhinoviruses, coronaviruses, adenoviruses and enteroviruses being the most common. They spread through the air or indirectly through contact with objects in the environment, followed by transfer to the mouth or nose. Risk factors include going to child care facilities, not sleeping well, and psychological stress. The symptoms are mostly due to the body's immune response to the infection rather than to tissue destruction by the viruses themselves. The symptoms of influenza are similar to those of a cold, although usually more severe and less likely to include a runny nose.

Ultraviolet germicidal irradiation (UVGI) is a disinfection technique employing ultraviolet (UV) light, particularly UV-C (180–280 nm), to kill or inactivate microorganisms. UVGI primarily inactivates microbes by damaging their genetic material, thereby inhibiting their capacity to carry out vital functions.

The use of UVGI extends to an array of applications, encompassing food, surface, air, and water disinfection. UVGI devices can inactivate microorganisms including bacteria, viruses, fungi, molds, and other pathogens. Recent studies have substantiated the ability of UV-C light to inactivate SARS-CoV-2, the strain of coronavirus that causes COVID-19.

Coronavirus disease 2019 (COVID-19) is a contagious disease caused by the coronavirus SARS-CoV-2. In January 2020, the disease spread worldwide, resulting in the COVID-19 pandemic.

The symptoms of COVID‑19 can vary but often include fever, fatigue, cough, breathing difficulties, loss of smell, and loss of taste. Symptoms may begin one to 14 days after exposure to the virus. At least a third of people who are infected do not develop noticeable symptoms. Of those who develop symptoms noticeable enough to be classified as patients, most (81%) develop mild to moderate symptoms (up to mild pneumonia), while 14% develop severe symptoms (dyspnea, hypoxia, or more than 50% lung involvement on imaging), and 5% develop critical symptoms (respiratory failure, shock, or multiorgan dysfunction). Older people have a higher risk of developing severe symptoms. Some complications result in death. Some people continue to experience a range of effects (long COVID) for months or years after infection, and damage to organs has been observed. Multi-year studies on the long-term effects are ongoing.

Novel coronavirus (nCoV) is a provisional name given to coronaviruses of medical significance before a permanent name is decided upon. Although coronaviruses are endemic in humans and infections normally mild, such as the common cold (caused by human coronaviruses in ~15% of cases), cross-species transmission has produced some unusually virulent strains which can cause viral pneumonia and in serious cases even acute respiratory distress syndrome and death.

Severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1), previously known as severe acute respiratory syndrome coronavirus (SARS-CoV), is a coronavirus that causes severe acute respiratory syndrome (SARS), the respiratory illness responsible for the 2002–2004 SARS outbreak. It is an enveloped, positive-sense, single-stranded RNA virus that infects the epithelial cells within the lungs. The virus enters the host cell by binding toangiotensin-converting enzyme 2. It infects humans, bats, and palm civets. The SARS-CoV-1 outbreak was largely brought under control by simple public health measures. Testing people with symptoms (fever and respiratory problems), isolating and quarantining suspected cases, and restricting travel all had an effect. SARS-CoV-1 was most transmissible when patients were sick, so its spread could be effectively suppressed by isolating patients with symptoms.

On April 16, 2003, following the outbreak of SARS in Asia and secondary cases elsewhere in the world, the World Health Organization (WHO) issued a press release stating that the coronavirus identified by a number of laboratories was the official cause of SARS. The Centers for Disease Control and Prevention (CDC) in the United States and the National Microbiology Laboratory (NML) in Canada identified the SARS-CoV-1 genome in April 2003. Scientists at Erasmus University in Rotterdam, the Netherlands, demonstrated that the SARS coronavirus fulfilled Koch's postulates, thereby confirming it as the causative agent. In the experiments, macaques infected with the virus developed the same symptoms as human SARS patients.