Coronaviruses are types of viruses that typically affect the respiratory tracts of birds and mammals, including humans. Doctors associate them with the common cold, bronchitis, pneumonia, severe acute respiratory syndrome (SARS), and COVID-19. They can also affect the gut.
Coronaviruses are a family of viruses that cause disease in animals. Seven, including the new virus, have made the jump to humans, but most just cause cold-like symptoms.
Two other coronaviruses – Middle East respiratory syndrome (Mers) and severe acute respiratory syndrome (Sars) – are much more severe, having killed more than 1,500 people between them since 2002.
The new virus, officially called Covid-19, is also dangerous – so far, around 20 per cent of confirmed cases have been classed as severe or critical. So far, around 15 to 20 per cent of hospital cases have been classed as “severe” and the current death rate varies between 0.7 per cent and 3.4 per cent depending on the location and, crucially, access to good hospital care.
This is much lower than fatality rates for Mers (30 per cent) and Sars (10 per cent), but still a significant threat.
Scientists in China believe that Covid-19 has mutated into two strains, one more aggressive than the other, which could make developing a vaccine more complicated.
Coronavirus vs COVID-19
Scientists first found evidence of human coronaviruses (HCoV) in the 1960s in the noses of people with the common cold. Two human coronaviruses are responsible for a large proportion of common colds: OC43 and 229E.
The name “coronavirus” comes from the crown-like projections on their surfaces. “Corona” in Latin means “halo” or “crown.”
Among humans, coronavirus infections most often occur during the winter months and early spring. People regularly become ill with a cold due to a coronavirus and may catch the same one about 4 months later.
This is because coronavirus antibodies do not last for a long time. Also, the antibodies for one strain of coronavirus may be ineffective against another one.
In 2019, the Centers for Disease Control and Prevention (CDC) started monitoring the outbreak of a new coronavirus, SARS-CoV-2, which causes the respiratory illness now known as COVID-19. Authorities first identified the virus in Wuhan, China.
More than 78,191 people have contracted the virus in China. Health authorities have identified many other people with COVID-19 around the world, including in the United States. On January 31, 2020, the virus passed from one person to another in the U.S.
The World Health Organization (WHO) have declared a public health emergency relating to COVID-19.
Since then, this strain has been diagnosed in several U.S. residents. The CDC have advised that it is likely to spread to more people. COVID-19 has started causing disruption in at least 25 other countries.
The first people with COVID-19 had links to an animal and seafood market. This fact suggested that animals initially transmitted the virus to humans. However, people with a more recent diagnosis had no connections with or exposure to the market, confirming that humans can pass the virus to each other.
Information on the virus is scarce at present. In the past, respiratory conditions that develop from coronaviruses, such as SARS and MERS, have spread through close contacts.
On February 17, 2020, the Director-General of the WHO presented at a media briefing the following updates on how often the symptoms of COVID-19 are severe or fatal, using data from 44,000 people with a confirmed diagnosis:
|Stage of severity||Rough percentage of people with COVID-19|
|Mild disease from which a person can recover||More than 80%|
|Severe disease, causing breathlessness and pneumonia||Around 14%|
|Critical disease, including septic shock, respiratory failure, and the failure of more than one organ||About 5%|
The Director-General also noted that the risk of serious complications increases with age. According to the WHO, few children get COVID-19, although they are still investigating the reasons for this.
However, while some viruses are highly contagious, it is less clear how rapidly coronaviruses will spread.
Symptoms of COVID-19
Symptoms vary from person-to-person with COVID-19. It may produce few or no symptoms. However, it can also lead to severe illness and may be fatal. Common symptoms include:
It may take 2–14 days for a person to notice symptoms after infection.
No vaccine is currently available for COVID-19. However, scientists have now replicated the virus. This could allow for early detection and treatment in people who have the virus but are not yet showing symptoms.
The National Institutes of Health (NIH) suggest that several groups of people have the highest risk of developing complications due to COVID-19. These groups include:
- young children
- people aged 65 years or older
- women who are pregnant
The CDC advise that although there have been reports of complications in young children, these are rare. COVID-19 most commonly produces mild symptoms in children.
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