COVID – 19 Infection Specialist Doctor In Mumbai Coronaviruses are important human and animal pathogens. At the end of 2019, a novel coronavirus was identified as the cause of a cluster of pneumonia cases in Wuhan, a city in the Hubei Province of China. It rapidly spread, leading to a global pandemic. In February 2020, the World Health Organization designated the disease COVID – 19, which stands for coronavirus disease 2019.. The virus that causes COVID – 19 is designated as severe acute respiratory syndrome coronavirus 2 ( SARS–CoV–2 ). Like other viruses, SARS-CoV-2 evolves over time. Certain variants have garnered widespread attention because of their rapid emergence within populations and evidence for transmission or clinical implications; these are considered variants of concern. The Omicron variant ( B.1.1.529 ) was first reported from Botswana and very soon thereafter from South Africa in November 2021. It was promptly identified in multiple other countries, where it was associated with sharp increases in reported infections. The Omicron has a replication advantage and evades infection and vaccine induced immunity to a greater extent than prior variants. It appears to be associated with less severe disease than other variants. The Delta ( B.1.617.2 ) lineage was first identified in India in December 2020 and had since been the most prevalent variant worldwide until emergence of the Omicron variant. It was more transmissible, and was associated with a higher risk of severe disease and hospitalization. Direct person - to – person respiratory transmission is the primary means of transmission of SARS-CoV-2. It is thought to occur mainly through close range contact ( ie, within approximately six feet or two meters ) via respiratory particles; virus released in the respiratory secretions when a person with infection coughs, sneezes, or talks can infect another person if it is inhaled or makes direct contact with the mucous membranes. Infection might also occur if a person’s hands are contaminated by these secretions or by touching contaminated surfaces and then they touch their eyes, nose, or mouth, although contaminated surfaces are not thought to be a major route of transmission. The long - range airborne transmission is not a primary mode. The potential to transmit SARS-CoV-2 begins prior to the development of symptoms and is highest early in the course of illness. The risk of transmission after contact with an individual with COVID – 19 increases with the closeness and duration of contact and appears highest with prolonged contact in indoor settings. Transmission of SARS- CoV-2 from individuals with infection but no symptoms has been well documented. Prior to emergence of the Omicron variant, the short term risk of reinfection was low. However, the risk of reinfection with Omicron variant in individuals previously infected with other variants is higher; the risk of reinfection with Omicron variant after a prior Omicron infection is uncertain but likely low. The clinical spectrum of SARS-CoV-2 infection ranges from asymptomatic infection to critical and fatal illness. Most symptomatic infections are mild. Severe disease has been reported in 15 to 20 percent of symptomatic infections in unvaccinated individuals; it can occur in otherwise healthy individuals of any age, but predominantly occurs in adults with advanced age or certain underlying medical comorbidities. The incubation period from the time of exposure until the onset of symptoms is three to five days on average, partly depending on the variant, but it may be as long as 14 days. The most commonly reported symptoms are cough, body ache, and headache. Other features, including diarrhea, sore throat, and smell or taste abnormalities are also well described. Mild upper respiratory symptoms ( eg, nasal congestion, sneezing ) appear to be more common with the Delta and Omicron variants. Pneumonia, with fever, cough, breathlessness is the most frequent serious manifestation of infection. Acute respiratory distress syndrome ( ARDS ) is the major complications in patients with severe disease. The other complications of severe illness include clotting abnormalities, acute cardiac injury, kidney injury. RT – PCR assay to detect SARS-CoV-2 from the upper respiratory tract is the preferred initial diagnostic test for COVID – 19. Antigen tests can be performed rapidly but they are less sensitive than RT – PCR. Outpatient management is appropriate for most patients with COVID – 19. The patient should be evaluated by a specialist at the earliest to look for risk factors for severe disease. The patient should be under the guidance of a specialist throughout the course of the treatment. The patient complaining of breathlessness, having low oxygen saturation, low blood pressure, confusion or change in behavior should be admitted. The personal measures to reduce the risk of transmission include wearing of mask, diligent hand washing, respiratory hygiene, physical distancing, and avoiding crowds, poorly ventilated areas, and close contact with ill individuals. Vaccines to prevent SARS-CoV-2 infection are considered the most promising approach for curbing the pandemic. All eligible persons should get themselves vaccinated under the guidance of a specialist. The booster doses must be given to the appropriate persons.