COVID19viruksen

COVID19viruksen refers to the virus that causes the disease COVID-19, officially named SARS-CoV-2. It is a coronavirus in the family Coronaviridae and the genus Betacoronavirus. The virus is enveloped and has a positive-sense single-stranded RNA genome. Its surface is studded with spike proteins that mediate entry into host cells by binding the ACE2 receptor.

Transmission occurs mainly through respiratory droplets and aerosols produced when an infected person talks, breathes, coughs, or sneezes. It can spread from people with mild symptoms or from those who are asymptomatic. The incubation period is typically 2 to 14 days. The clinical spectrum ranges from asymptomatic or mild upper respiratory tract infection to severe pneumonia, acute respiratory distress syndrome, and multi-organ failure. Age and underlying health conditions increase the risk of severe outcomes.

Since its emergence in late 2019, several variants of concern have been identified, including Alpha, Beta, Gamma, Delta and Omicron, with mutations that can affect transmissibility and immune escape. Public health responses include vaccination, testing, masking, ventilation, and physical distancing. Vaccines against SARS-CoV-2 include mRNA vaccines (such as those by Pfizer-BioNTech and Moderna), viral vector vaccines (such as AstraZeneca and Johnson & Johnson), and inactivated vaccines (such as Sinovac and Sinopharm). Vaccination reduces the risk of severe disease and death, with booster doses commonly recommended.

Treatment options include antiviral medicines (for example, nirmatrelvir-ritonavir and remdesivir) and supportive care. Access to therapies varies by region. Some people experience long-term effects after infection, known as long COVID. Ongoing surveillance and research monitor new variants, evaluate vaccines for breadth of protection, and refine public health guidance.