Give information about covid 19
in 1000 words
Answers
1. What is SARS-CoV-2? What is COVID-19?
Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the name given to the 2019 novel coronavirus. COVID-19 is the name given to the disease associated with the virus. SARS-CoV-2 is a new strain of coronavirus that has not been previously identified in humans.
2 Where do coronaviruses come from?
Coronaviruses are viruses that circulate among animals, with some infecting humans.
Bats are considered natural hosts of these viruses, and several other species of animals are also known to act as sources. For instance, Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is transmitted to humans from camels, while Severe Acute Respiratory Syndrome Coronavirus-1 (SARS-CoV-1) is transmitted to humans from civet cats.
3 Is this virus comparable with SARS or with the seasonal flu?
The novel coronavirus detected in China in 2019 is closely related genetically to the SARS-CoV-1 virus. SARS emerged in late 2002 in China, and caused more than 8 000 cases in 33 countries over the course of eight months. Around one in 10 of people who developed SARS died.
In the first eight months of the COVID-19 pandemic (from 31 December 2019 to 31 August 2020), there were over 25 million cases worldwide and more than 840 000 deaths.
While the viruses that cause both COVID-19 and seasonal influenza are transmitted from person to person and may cause similar symptoms, the two viruses are different.
ECDC estimates that between 15 000 and 75 000 people die prematurely every year in the European Union (EU), the United Kingdom (UK), Norway, Iceland and Liechtenstein due to causes associated with seasonal influenza infection. This represents approximately one in every 1 000 people who are infected. Despite the relatively low mortality rate for seasonal influenza, many people die from the disease due to the large number of people who contract it each year. Unlike influenza, there is not yet a vaccine for COVID-19, and only limited treatment options are currently available for the disease. It also appears to be more transmissible than seasonal influenza, although it has a milder clinical course in young children. As it is a new virus, nobody has prior immunity to it, which means that the entire human population is potentially susceptible to SARS-CoV-2 infection.
4 How does the virus spread?
SARS-CoV2 spreads from person to person (human-to-human transmission) through direct contact. It is currently estimated that, in the absence of physical distancing and other preventive measures, one infected person will on average infect between two and three other people.
The virus is transmitted mainly via respiratory droplets and aerosols when sneezing, coughing, or interacting with others in close proximity (usually less than two metres. These droplets can be inhaled or can land on surfaces that others come into contact with and are then infected when they touch their nose, mouth or eyes. The virus can survive on surfaces from between several hours (copper, cardboard) up to a few days (plastic and stainless steel). However, the amount of viable virus declines over time and may not always be present in a sufficient amount to cause infection.
The incubation period for COVID-19 (i.e. the time between exposure to the virus and the onset of symptoms) is currently estimated to be between one and 14 days.
We know that the virus can be transmitted when people who are infected show symptoms such as coughing. A person who is infected can also transmit the virus up to two days before they show symptoms; the extent to which such asymptomatic infections contribute to the overall transmission is not currently clear.
6 When is a person infectious?
The infectious period may begin up to two days before symptoms appear, but people are most infectious during the symptomatic period, even if symptoms are mild and non-specific. The infectious period is estimated to last for eight to 10 days in moderate cases, and up to two weeks on average in severe cases.
7 How severe is COVID-19 infection?
Data from the EU/European Economic Area (from the countries with available data) show that around 20–30% of diagnosed COVID-19 cases are hospitalised, and 2% of those have severe illness. It is important to note, however, that people with more severe symptoms are more likely to be tested than those with less severe symptoms. The real proportion of people requiring hospital admission from the overall number of infected individuals is therefore lower than these figures suggest. Hospitalisation rates are higher for those aged 60 years and above, and for those with underlying health conditions.