Symptoms and diagnosis of coronavirus disease (COVID-19)

The disease caused by the new coronavirus is called COVID-19. This information is a summary of its symptoms and how COVID-19 is diagnosed. Older people and those with dementia often have different symptoms from working-age adults.

Most of us are now familiar with the common symptoms of coronavirus such as fever, cough and loss of taste/smell. However, an older person or someone with dementia may not have any of these, but other symptoms instead. Being aware of these can be helpful.

We have advice on what to do if a person living with dementia becomes ill at home. This tells you who to contact and what to do if the person gets worse. We also have advice on supporting someone in hospital.

Symptoms of COVID-19

Infection with coronavirus can cause a wide range of symptoms – and in some cases none at all. People may have mild or severe illness. Symptoms can also differ between children, adults under 65 and those who are older, including people with dementia. 

Overall, about 80 people in 100 with coronavirus infection get either no symptoms or mild COVID-19 (which is treatable at home). About 20 in 100 get severe COVID-19 that needs hospital care.

Mild illness

Coronavirus infects the airways and lungs first. Symptoms appear about five to seven days after infection. The ‘typical’ first symptoms seen in many adults under the age of 65 are one or more of:

  • high temperature (fever)
  • new continuous cough
  • loss of, or change in, sense of smell or taste. 

Some people also get shortness of breath, often about a week or so after the first symptoms. These symptoms mean that even ‘mild’ COVID-19 that doesn’t require medical treatment can still make it difficult to get on with day-to-day activities such as cleaning or cooking.

A lot of other symptoms of COVID-19 are seen in adults under the age of 65, but less often – for some symptoms only in 1 in 10 people. These ‘atypical’ symptoms include:

  • delirium 
  • loss of appetite
  • diarrhoea or vomiting
  • weakness and fatigue
  • muscle or joint pain 
  • dizziness or falls.

Unlike fever, cough and loss of taste/smell, these less common symptoms are not widely mentioned in NHS information.

Severe illness

The most common symptoms of severe COVID-19 in adults under the age of 65 are severe difficulties with breathing (respiratory failure) that have come on over hours or a few days. These may develop once the fever has gone and the person seems to be getting better. They include one or more of:

  • struggling to breathe
  • coughing up blood
  • blue lips or a blue tinged face
  • skin that is cold and clammy, pale or blotchy.

Coronavirus in the most severely ill patients can also affect other organs and body systems, not just the airways and lungs. These include the blood (especially clotting and sepsis), kidney, liver, heart and brain. Symptoms may then include:

  • a rash that does not fade when you roll a glass over it (possible sepsis)
  • collapsing or feeling faint
  • confusion or feeling very drowsy (possible delirium)
  • stopping urinating (peeing) or peeing much less than usual (possible kidney failure).

If someone has any of the eight symptoms listed above, call 999 and ask for an ambulance.

Symptoms in older people and people with dementia

The symptoms of COVID-19 in older people over the age of 65 are often different from those in younger adults.

An older person, especially over about 75, is more likely to have atypical symptoms early on – if they have any at all. In several studies, only a minority of older people with COVID-19 had a fever, usually seen as a ‘typical’ symptom. 

Older people may not feel always feel short of breath either – even when their blood may have dangerously low amounts of oxygen in it. Instead, they may have fast, shallow breathing and a fast pulse. 

A person’s chance of having atypical symptoms rises as they get older, become frailer and have more long-term conditions (including dementia, heart disease and diabetes). This is particularly important for those living in care homes, most of whom would be in this category.

People with dementia who get coronavirus infection are at particular risk of delirium. Over the space of hours or a few days they may become unusually withdrawn and sleepy. Less often they may become more confused, agitated or disorientated. Any of these symptoms of delirium can seem a bit better or worse (fluctuate) over the day.

Older people with COVID-19 may start with what seem to be only mild symptoms (for example, diarrhoea and loss of appetite) but get worse quickly. It may be that they were actually much more seriously unwell than their symptoms first suggested. If the person has dementia, then they may be less able to tell someone that they are in pain or feel sick in the first place.

Why do the differences in COVID-19 symptoms matter?

These differences in the symptoms of COVID-19 are really important. A family member or care home worker could be looking out for fever, cough or shortness of breath as a sign of coronavirus in a frail person in their 80s. They will miss the virus if the person lacks these symptoms but instead seems fatigued, withdrawn and with fast breathing. This is one reason why regular testing for the virus in care home residents and staff is so important.

Diagnosis of COVID-19

Mild illness

Someone will be suspected of having mild COVID-19 if their symptoms and how they developed (‘clinical history’) suggest this.

Anyone with symptoms should self-isolate and ask for a home test for the virus. A positive test result means the person currently has coronavirus infection.

Severe illness

Diagnosing someone with suspected severe COVID-19 will involve a combination of:

  • clinical history
  • assessment of mental status
  • physical examination
  • vital signs (temperature, blood pressure, heart rate, breathing rate)
  • oxygen levels in the blood
  • chest x-ray
  • a swab – the test for active coronavirus infection
  • blood tests – including immune response, clotting, and kidney and liver function.

To have all of these tests done, the person will need to be in hospital. But some routine checks (for example, vital signs) can be done in a care home, especially a nursing home. 

Checking blood oxygen levels is very important and will be done using a pulse oximeter. This medical device is inexpensive and can be used in a care home. It fits painlessly over a fingertip.

Knowing how much oxygen someone has in their blood can be really helpful. As explained above, an older person in particular may have dangerously low levels of blood oxygen – and so be seriously ill – without many, sometimes any, typical symptoms. 

Further advice

If you ever need any advice for symptoms, visit NHS 111 online or call 111 (or the GP) unless they seem urgent. In that case, call 999.

NHS 111 online
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