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What is the difference between the common cold, influenza (flu) and COVID-19?

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Updated 3rd September 2020 - We recommend the coronavirus page on the NHS website for more up to date information. 

The flu

Influenza or ‘flu is an infection of the respiratory system caused by strains of the influenza virus and is especially common in winter.

Symptoms generally include:

  • High fever
  • Headache
  • Aches and pains
  • Sore throat
  • Tiredness

After exposure to the flu, symptoms tend to come on very quickly and are more intense than the common cold, but are unlikely to cause hospitalisation unless you’re in a high-risk category.

The COVID-19 pandemic

COVID-19 is a respiratory illness caused by a novel (new) coronavirus first identified in Wuhan, Hubei Province, China. The virus has never been in circulation before, meaning no-one had previously built up immunity to it. Due to the fast rate it spread across the globe, coronavirus is considered a pandemic.

Main symptoms of COVID-19 include:

  • A high temperature
  • A loss or change to your sense of taste and smell
  • A new, continuous cough

If you have symptoms and tested positive, had an unclear result or did not have test you should self-isolate for at least 10 days. You should also self-isolate if you tested positive but haven’t had symptoms. You should self-isolate for 14 days if you live with (or are in a support bubble with) someone who has symptoms and tested positive, had an unclear result or did not have test or have tested positive but not had symptoms.

The common cold

The common cold is another respiratory illness caused by a different virus to the influenza virus and coronavirus. Symptoms of the common cold are similar to the flu but are usually much milder and more likely to accompany a runny or stuffy nose.

Similarities and differences in symptoms

Signs and symptoms Common cold Flu  COVID-19
Onset of symptoms Gradual Sudden Gradual or sudden
Fever Unlikely Common Common
Chills Unlikely Sometimes Sometimes
Body aches Unlikely Sometimes Sometimes
Fatigue (tiredness) Sometimes Common Common
Sneezing Common Sometimes Unlikely
Cough Sometimes Common Common
Sore throat Common Sometimes Sometimes
Headache Sometimes Common Sometimes
Runny or stuffy nose Common Sometimes Unlikely

 

Watch our video to find out more about the differences between flu, the common cold and COVID-19. 

Is the coronavirus disease more severe than the flu?

COVID-19 can, for some people cause more serious illness than seasonal influenza. That’s why it’s important to follow government advice and take appropriate precautions to keep you and those around you safe and well.

Both can result in severe complications, such as:

  • Respiratory failure – a condition where not enough oxygen passes from your lungs into your blood
  • Pneumonia – an infection in one or both lungs that causes swelling and fluid to build up, causing difficulty in breathing
  • Sepsis – when the immune system goes into overdrive in reaction to an infection, and begins to damage the body’s own tissues and organs
  • Multiple organ failure – where two or more organ systems begin to shut down
  • Worsening of pre-existing conditions – for example asthma or heart disease
  • Secondary bacterial infections – a second infection that occurs as a result of the damage caused by the initial influenza or COVID-19 infection

Whilst the flu and COVID-19 share similar symptoms and potential complications, COVID-19 has, in some cases, shown to have additional complications associated with it, such as:

  • Blood clots – clots in the veins or arteries of the heart, lungs, legs or brain have presented themselves in more severely ill patients, leading to strokes or amputations
  • Paediatric multisystem inflammatory syndrome associated with COVID-19 – a condition where different parts of the body become inflamed.

Currently, more people are susceptible to COVID-19 because no-one has immunity yet, and there isn’t a vaccine currently available, unlike flu, therefore the disease is considered more severe.

Flu deaths vs coronavirus deaths

According to the WHO (World Health Organisation), seasonal flu generally kills fewer than 1% of those infected. In contrast to this, 3.4% of reported COVID-19 cases have resulted in death. 

Common cold death rate

Symptoms of the common cold are mild and are unlikely to lead to serious complications.

Transmission differences

COVID-19, the common cold and flu can all spread from person to person through tiny droplets in the air caused by coughing, sneezing or talking. A virus can also exist on surfaces and spread when a person touches a contaminated surface and then touches their face. In all cases, transmission can occur in people who are asymptomatic (do not show any symptoms) or even before symptoms begin to show.

A unique element of COVID-19’s transmission is that certain populations and age groups are at a higher risk of being seriously ill than they are with the flu or common cold.

Who is more at risk from coronavirus?

On top of being in a high risk category, Public Health England have identified the following factors that may place you more at risk of catching COVID-19:

  • Being a man (men appear more susceptible to COVID-19)
  • Where in the country you live, as the risk is higher in poorer more crowded areas
  • Being from a Black, Asian or Minority Ethnic (BAME) background
  • Living in a care home
  • Having certain high-exposure jobs such as nurse or bus driver

How is the transmission of COVID-19 in children different from flu?

Whilst data gathering is still in the early phases, it does appear that children are less affected by the COVID-19 virus than adults. This is in contrast to the flu, where children are equally affected and significantly drive influenza transmission rates within a community. 

How to stay safe?

Here are some examples of ways to keep yourself safe from viruses:

  • Frequently wash hands with soap and warm water for at least 20 seconds. If soap and water is not available, use a hand sanitising gel.
  • Avoid touching your nose, eyes and mouth when out and about, as viruses can linger on surfaces and enter the body in this way.
  • Stay away from infected people and keep your distance from those not in your household. 
  • Keep healthy – ensure you maintain a healthy diet and proper exercise.
  • Use face coverings, such as face masks – this limits the spread of virus-spreading droplets in the air, and is especially important during the COVID-19 pandemic.

References

www.nhs.uk/conditions/flu/
www.nhs.uk/conditions/coronavirus-covid-19/symptoms/
www.cdc.gov/flu/symptoms/coldflu.htm
www.cdc.gov/flu/symptoms/flu-vs-covid19.htm
www.who.int/dg/speeches/detail/who-director-general-s-opening-remarks-at-the-media-briefing-on-covid-19---3-march-2020
www.cdc.gov/flu/prevent/actions-prevent-flu.htm
www.nhs.uk/conditions/coronavirus-covid-19/people-at-higher-risk/whos-at-higher-risk