There are three main symptoms of coronavirus. If you get just one of them, you should get a test.
What are the symptoms?
- New and continuous cough - coughing a lot for more than an hour, or having three or more coughing episodes in 24 hours
- Fever - a temperature above 37.8C
- Change in smell or taste - either you cannot taste or smell anything, or these senses are different to normal.
Public Health England says about 85% of people with Covid will have at least one.
If you have any of these symptoms you should get a test as soon as possible and not leave home for any other reason.
Anyone you live with, or who is in your support bubble, should also self-isolate until the test result arrives.
It takes five days on average from the moment you are infected to start showing the symptoms, but the World Health Organization says it can take up to 14 days.
If the test is positive, your whole household must all continue to follow self-isolation rules.
Is Covid the same in everyone?
No. The coronavirus can affect multiple organs and has several less common symptoms.
Scientists using data on the health of four million people say Covid has six sub-types.
- Flu-like with no fever: Headache, loss of smell, muscle pains, cough, sore throat, chest pain, no fever
- Flu-like with fever: Headache, loss of smell, cough, sore throat, hoarseness, fever, loss of appetite
- Gastrointestinal: Headache, loss of smell, loss of appetite, diarrhoea, sore throat, chest pain, no cough
- Fatigue (severe level one): Headache, loss of smell, cough, fever, hoarseness, chest pain, fatigue
- Confusion (severe level two): Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain
- Abdominal and respiratory (severe level three): Headache, loss of smell, loss of appetite, cough, fever, hoarseness, sore throat, chest pain, fatigue, confusion, muscle pain, shortness of breath, diarrhoea, abdominal pain
And researchers think that vomiting, diarrhoea and abdominal cramps could be a sign of coronavirus infection in children.
If I have a cough, is it definitely Covid?
Lots of other viruses have similar symptoms to Covid, including flu and other infections. This will be a particular problem over winter when these bugs are more common.
Public Health England says just under half of people who have one of the three main Covid symptoms will not have it.
However, they should still get a test.
What should I do if I have Covid?
If you have a positive test result you should self-isolate at home for at least 10 days from the time symptoms started.
You must stay away from other members of your household, who must self-isolate for at least 14 days.
Most people will have only mild symptoms, which can be managed with pain relief (like paracetamol), bed rest and plenty of fluids.
You should not even go to a GP surgery, pharmacy or hospital.
When should people go to hospital?
If you are seriously unwell and you have a medical emergency you should call 999 - this includes feeling so breathless that you cannot speak more than a few words.
The main reason people need hospital care is for difficulty breathing where they may be given oxygen.
The most seriously ill patients may require ventilation where the patient is sedated and air is pushed into their lungs.
Older people, and those with pre-existing medical conditions (such as asthma, diabetes, heart disease, high blood pressure), are more likely to become severely ill. Men are at slightly higher risk of dying from the virus than women.
How do I protect myself?
The best thing is regular and thorough hand washing, preferably with soap and water.
Coronavirus spreads when an infected person coughs or sneezes small droplets - packed with the virus - into the air. These can be breathed in, or cause an infection if you touch a surface they have landed on, then your eyes, nose or mouth.
So, coughing and sneezing into tissues, not touching your face with unwashed hands, and avoiding close contact with infected people are important.
People will be most infectious when they have symptoms, but some may spread the virus even before they are sick.
Face coverings are also compulsory in many indoor settings across the UK.
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