Health

What Is Coronavirus (COVID-19)?

Evidence Based Article 📄
This article has been based on relevant and up-to-date scientific studies. Our writers are unbiased and objective and present the facts as they are known. Numbers in brackets within the article refer to sources included in the reference list at the end of the article.

What are Coronaviruses?

Coronaviruses are a group of viruses that usually infect animals.  Rarely, they can be passed to humans and then spread between people.

The symptoms caused in humans are usually respiratory or gastrointestinal and can range from a common cold to severe infections like pneumonia.  Many coronaviruses are found in bats but can be spread to humans via other animals.

Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) were both caused by coronaviruses which originated in animals then spread to people; MERS via camels and SARS via civet cats.

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Covid-19 is a previously unknown coronavirus, and the animal source and/or intermediary has yet to be discovered.

The formal name of the virus, given by the International Committee on Taxonomy of Viruses, is the ‘severe acute respiratory syndrome coronavirus 2’ (SARS-CoV-2) because it is related to the virus which caused the 2003 SARS outbreak. However, to avoid confusion, the World Health Organisation assigned the name Covid-19, as a shortened version of coronavirus 2019 (1).

How did the COVID-19 outbreak start?

The first known incidence of Covid-19 was in December 2019 in the city of Wuhan in China.

The new virus was detected in three patients with pneumonia, among a cluster of cases of acute respiratory illness.

On the 31st December 2019, the Wuhan Municipal Health Commission reported a cluster of 27 pneumonia cases with a common link to the Huanan Seafood Wholesale Market, a live animal and seafood market.

Samples from the market tested positive for the new coronavirus, suggesting that the virus was passed to humans from an animal source within the market.

Because Covid-19 is a new virus, there is no existing human immunity which would reduce the numbers affected.

Instead, it spread rapidly within China and, by the 20th January 2020, it had also been carried by air travellers to three other countries in Asia, and the first European case was confirmed in France on the 24th January 2020 in someone who had recently travelled from China.

By the end of February, Covid-19 was spreading locally within several countries including Europe.

How is COVID-19 Transmitted?

Covid-19 is transmitted in much the same way as other viruses are transmitted.

  • Through small liquid droplets in the air from an infected person’s coughs or sneezes

These can be breathed in by other people in close proximity.

  • Through virus microbes on surfaces which have been touched by an infected person whose hands are not clean, or a surface on which liquid droplets have landed

Microbes can be transferred to a non-infected person’s eyes, nose or mouth if they touch their faces after their hands have been in contact with an infected surface.  The virus can then enter the body.

A recent analysis published by the New England Journal of Medicine (2) found that the Covid-19 virus can remain viable in the air for up to 3 hours, on copper for up to 4 hours, on cardboard for up to 24 hours and on plastic and stainless steel for up to 72 hours (albeit at a reduced level).

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This can, however, be affected by temperature.  A February 2020 study of coronaviruses (3), published in The Journal of Hospital Infection, found that some don’t remain active for as long a period at temperatures higher than 86ºF / 30ºC.

With a possible incubation period of 1-14 days, people can be infected long before they develop symptoms.  This does not prevent them passing on the infection to others.

Large numbers of confirmed cases of Covid-19 were not experiencing symptoms at the time of diagnosis, and cases have been reported of these non-symptomatic individuals transmitting the infection to others before their own symptoms appeared.

The virus has also been found to remain in the system for up to a month, although it is unclear whether the person remains infective.

What are The Symptoms?

Symptoms can vary between individuals, and also depending on the severity of the case, with the milder symptoms being similar to those of typical influenza, including:

  • fever
  • dry cough
  • fatigue
  • sputum production
  • difficulty breathing
  • sore throat
  • headache
  • muscle or joint pain

(Listed in order of most common to least common as reported in laboratory-confirmed cases in China and quoted on the European Centre for Disease Prevention and Control website)

There have also been less commonly reported symptoms of diarrhoea and vomiting.

Younger people with no underlying health conditions are more likely to experience milder symptoms.  In China, about 80% of reported cases were mild to moderate.

Older people, and those with underlying health conditions are more likely to develop serious symptoms, such as severe pneumonia, acute respiratory distress syndrome, multiple organ failure, sepsis and septic shock, which can lead to death.

Who is high risk for severe disease?

Based on data from China, certain groups of people have been identified as being at greater risk of developing severe symptoms.

Although most people will develop only mild symptoms and the risk of death is around 1%, the death rate among those who are infected in certain groups appears to be as high as 10%.

The Public Health England website (4) lists the following groups as being at higher risk of serious illness:

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(Although scientific evidence isn’t available about the risk to pregnant women, they are known to be at higher risk of complications from similar viruses such as SARS.) (5)

How is COVID-19 Diagnosed?

The only method of confirming a diagnosis is by testing samples of saliva/sputum, and via throat swab and nasal swab.  Due to the limited availability of testing kits, mass testing has not been possible everywhere and it is likely that there are many more people infected with coronavirus than the numbers of confirmed cases.

People with the symptoms described, especially those who might have been in contact with a confirmed case, should assume that they are infected by Covid-19 and follow their local guidelines for quarantine/isolation.

What is The Treatment?

There is no current direct treatment for Covid-19.

Those with less serious cases can relieve symptoms with painkillers, cough syrup, adequate fluid intake and plenty of rest, while their bodies fight the illness.

Those who develop severe symptoms and require hospitalisation may be given oxygen or placed on a ventilator if they are unable to breathe on their own.

Multiple small clinical trials have been ongoing internationally.

In response to this, on the 18th March, 2020, the World Health Organisation launched an international trial (6) which will enable many countries to try the same treatments and compare the results to generate the data necessary to demonstrate which treatments are most effective.

Named the SOLIDARITY trial, and providing simplified procedures to enable even overloaded hospitals to participate, the drugs treatments to be trialled are:

  • The antiviral drug remdesivir, used to treat Ebola
  • A combination of two HIV drugs – lopinavir and ritonavir
  • Lopinavir and ritonavir plus interferon beta
  • The antimalarial drug chloroquine

These have all shown some evidence of effectiveness against Covid-19 either in lab or animal studies.

In the meantime, a drug called favipiravir, used in Japan originally to treat new strains of influenza, has been reported in recent media (7) to have shown promising results in clinical trials in Wuhan and Shenzhen in China.

Although the Japanese health ministry believe the drug to be less effective in people with severe symptoms, Japanese doctors have been using it in people with mild to moderate symptoms to stop the virus multiplying.

As the drug was originally designed for use in treating flu, it now needs to be approved for widespread use on Covid-19, something that will hopefully have happened by May, depending on when results of the clinical research are available.

How can infection be prevented?

Although work is in progress in countries across the world to develop a vaccine, with some already at trial stage, it is likely to be several months before a safe and effective vaccine will be available for widespread use.

In the meantime, a number of measures have been advised by the World Health Organisation (9) and the governments of individual countries, which can help to prevent the virus spreading.

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Wash your hands frequently

Washing your hands with soap and water, or cleaning them with an alcohol-based hand rub kills any germs that might be on your hands.

Soap and water is the most effective method, as soap molecules destroy and dislodge the molecules, but it must be done properly.  Wash your hands frequently for at least 20 seconds, following these steps:

Particularly important times to wash your hands are before leaving the house, when you arrive at work or return home, after touching any surface that is potentially contaminated and after blowing your nose or catching a cough or sneeze.

If soap and water aren’t readily available, the (US-based) Centre for Disease Control (10) recommends using a hand sanitiser that contains at least 60% alcohol.  Cover all surfaces of your hands and rub them together until they feel dry.

Avoid touching your face

Touching your face transfers virus microbes from your hands to your mouth, nose and eyes.

Clean surfaces

According a study (3) published in February in The Journal of Hospital Infection, coronaviruses can be effectively removed with household disinfectants.

Wiping surfaces down with disinfectant wipes will reduce the risk of spreading Covid-19 by touch.

Maintain social distancing

Avoid unnecessary social contact and keep at least 1 metre (3 feet) away from other people, especially if they are coughing or sneezing.

Practise good respiratory hygiene

Cover your mouth and nose with a tissue or with your sleeve, when you cough or sneeze, then bin the tissue and wash your hands with soap and water, or use alcohol-based hand sanitiser.

Stay home if you have symptoms

If you develop any symptoms such as a fever or a cough, stay home.  Try to limit contact with other members of your household.

Comply with any local restrictions

Your local government might have introduced additional rules or restrictions such as:

  • Bans on groups of more than a certain number of people
  • Closure of restaurants, pubs, clubs, houses of worship, schools etc
  • Working from home
  • Quarantine for people who have been in contact with someone who is suspected to be infected

You might find these restrictions inconvenient but it is vital that you comply.  Extreme measures are needed to stop or slow the spread of the virus and protect vulnerable people.

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