COVID-19 is a viral infection caused by a virus called SARS Coronavirus 2 (or SARS-CoV-2). SARS-CoV-2 is a new strain of coronavirus that had not been identified in humans before. It first emerged in Wuhan, China, in 2019.
We will now outline 10 key facts about COVID-19.
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What are coronaviruses, and where do they come from?
Coronaviruses are a group of viruses that can infect various animal species, such as bats, pigs, cats, or dogs. Some types of coronaviruses also affect humans and cause seasonal epidemics, typically in the winter months. The exact way in which SARS-CoV-2 was transmitted from animals to humans is still unknown.
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How does COVID-19 spread?
COVID-19 mainly spreads through respiratory droplets when an infected person sneezes, coughs, speaks, sings, or breathes near someone else.
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Can COVID-19 be caught by touching surfaces?
Rarely. Infection may occasionally occur through contact with surfaces contaminated with droplets.
The virus can survive on some surfaces for a few hours (e.g. copper, cardboard), and on others for up to several days (e.g. plastic and stainless steel). However, the amount of viable virus decreases over time, and it is rarely present on surfaces in sufficient quantities to cause infection.
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What are the symptoms of COVID-19?
The symptoms are very similar to those of other upper respiratory viral illnesses, such as colds and flu. These include:
- A high temperature or shivering (chills) – feeling hot to the touch on your chest or back
- A new, continuous cough
- A loss or change to your sense of smell or taste
- Shortness of breath
- Feeling tired or exhausted
- An aching body
- A headache, sore throat, or a blocked or runny nose
- Diarrhoea, or feeling sick, or being sick.
If you have any of these symptoms and a high temperature, or you do not feel well enough to go to work, college, or school, it is advised to stay at home and avoid contact with others.
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What types of COVID-19 infections are there?
At least a third of people who are infected are asymptomatic and do not develop noticeable symptoms.
Most infections are mild and last 5-6 days, with full recovery within two weeks. However, 5-10% of patients may develop ‘long COVID’, where symptoms persist 12 weeks after the initial infection (though there is no universally agreed definition of long COVID based on 12 weeks).
This is likely a form of ‘post-viral fatigue syndrome’, which is known to occur after other viral infections, such as Epstein-Barr Virus (EBV), which causes glandular fever.
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How long is a person infectious with COVID-19?
An infected person can transmit the virus up to two days before experiencing symptoms, as well as while symptomatic.
People with mild-to-moderate COVID-19 can remain infectious for up to 10 days after symptoms start.
Adults with severe-or-critical illness, or those with weakened immune systems (e.g. transplant patients on immunosuppressive drugs), may remain infectious for up to four weeks after symptoms begin.
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What is the incubation period for COVID-19?
The incubation period for COVID-19, which is the time between exposure to the virus and the onset of symptoms, is typically 5-6 days.
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Is there a cure for COVID-19, and what is the treatment?
No. Most people with COVID-19 do not require treatment.
Treatments for COVID-19 include antibody and antiviral medications, as well as steroids. However, these are only given to patients in hospital or those at risk of becoming seriously ill.
If you are at home with COVID-19, you can relieve mild symptoms by resting, drinking plenty of fluids, and taking paracetamol or NSAIDs (such as aspirin or ibuprofen).
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Do COVID-19 vaccines work?
Yes. The vaccines are effective, though not perfect. Fully vaccinated individuals can still contract COVID-19 (these are called ‘breakthrough infections’).
They may carry similar amounts of the virus as unvaccinated individuals, but vaccinated people tend to be less unwell and less infectious.
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How severe is COVID-19 infection?
Among those who develop noticeable symptoms, most (about 80%) experience mild symptoms, while 15% develop more severe symptoms, and 5% experience serious illness.
Patients with very severe disease may require ventilation (a breathing machine) in intensive care, and in some cases, this can lead to death.
The mortality rate for COVID-19 is about 1%, but this varies greatly depending on vaccination status, age, variant, and underlying health conditions (e.g. heart disease, diabetes, chronic respiratory disease, and cancer). Older age is the most significant risk factor.
Other information
Are pandemics new?
Pandemics are not new. They are mentioned in historical texts, such as the Bible and the Quran. In 1918-20, the Spanish flu, an influenza virus, likely caused over 50 million deaths.
In an average flu season, about 1 in 1,000 people who catch the flu will die. COVID-19 has a mortality rate of around 1%, but this increases to 5% for those aged 75 and 15% for those aged 85.
Vaccines for COVID-19 are available, whereas influenza vaccines were first developed in the 1930s.
Is COVID-19 similar to seasonal flu?
Yes and no. Both cause respiratory infections (affecting the upper airways and lungs), and the viruses that cause COVID-19 and seasonal flu spread between people in close contact.
Both are transmitted when infected individuals cough, sneeze, or talk. However, the virus that causes COVID-19 appears to spread more easily than influenza.
COVID-19 first appeared in late 2019 and spread rapidly across the globe. As SARS-CoV-2 was a new virus, most people had no immunity to it, meaning the entire human population was vulnerable to infection at the start of the pandemic.
It is difficult to know when an influenza virus first infected humans, but reports of flu pandemics go back hundreds of years.
