Impact on the Body

Patients with COVID-19 have had a wide range of symptoms reported from mild symptoms to severe illness. These may appear 2-14 days after exposure to the virus:

  • Fever

  • Fatigue

  • Cough

  • Shortness of breath or difficulty breathing

  • Chills

  • Repeated shaking with chills

  • Muscle pain

  • Headache

  • Sore throat

  • New loss of taste or smell


Most people will only display mild symptoms, but, individuals who are either older or have other illnesses will be more at risk from the disease progressing to the more serious form of COVID-19. These complications affect about 1 in 6 is mainly due to the immune system overreacting to the virus a condition called cytokine release syndrome or cytokine storm.

Chemical signals to the rest of the body cause inflammation, but these need to be delicately balanced as too much can cause collateral damage through the body.  The immune system floods the blood stream with inflammatory proteins called cytokines. They can kill tissue and damage organs including lungs, heart and kidneys.


Complications can be:


Silent Hypoxemia (Happy Hypoxia)

Here patients have extremely low levels of oxygen but do not show any signs of having difficulty breathing. The patient seems very comfortable but has oxygen level which would usually make them extremely short of breath.  One thought is that maybe the coronavirus is affecting how the body senses low levels of oxygen which could be linked to the lack of smell. More research is needed but this information may help to avoid mechanical ventilation.


If inflammation spreads to the lungs making it harder to breathe this is called pneumonia.

Acute Respiratory Failure

Here the lungs cannot pump enough oxygen into the blood or take enough carbon dioxide out, or both. In China this was the leading form of death from COVID-19.

Septic Shock 

The immune system is spiralling out of control and is causing damage throughout the body. This can lead to septic shock which is when blood pressure drops to very low levels and organs stop working properly or even fail completely.

Acute Respiratory Distress Syndrome (ARDS)

Caused by widespread inflation in the lungs, stops the body getting enough oxygen and can stop the kidneys from cleaning the blood and damage the lining of the intestines. If the immune system cannot get on the top of the virus, then it will eventually spread to every corner of the body where it can cause even more damage. At this stage, treatment can include extra corporeal membrane oxygenation which is an artificial lung that take blood out of the body through thick tubes, oxygenates it and pumps it back in.

Acute Liver Injury or Cardiac Injury

Hospitalised patients have a risk of liver damage or heart failure. It is not know if either of these are caused by the virus or the from the illness itself causing other forms of damage to the body.

Acute Kidney Infection

Not a common complication, but some patients do need dialysis for filter the blood if this happens.

Blood Clots

A condition called Disseminated Intravascular Coagulation can develop where the body's blood clotting response is not working leading to abnormal clots. This could lead to internal bleeding or organ failure.

Paediatric Inflammatory Multisystem Syndrome (PIMS-TS)

This Kawasaki-like illness is rare but has been seen in some children and teenagers who have tested positive for COVID-19. Symptoms can vary but main symptom is a persistent fever (for more than 3 days) and some may have a rash, stomach ace or diarrhoea. In April in the UK around 20 children had serious inflammation throughout their body.  


In severe cases the inflammation can spread to blood vessels and if untreated can cause issue damage, organ failure or even in very rare cases, death. The symptoms can overlap with other rare conditions such as Kawasaki disease and Toxic Shock Syndrome.

Long Covid

This appears to be a debilitating syndrome that follows a coronavirus infection. Studies have focused on people who were hospitalised but there are also reports of lasting illnesses after much milder cases.


There isn't an official definition but there are many reporting symptoms that can last for months. Prolonged chest pains, shortness of breath and fatigue are often mentioned. Some have lasting damage to their heart and lungs and blood clots that cause swelling or strokes. Researchers are looking at whether or not the symptoms are a result of a number of different syndromes.