Symptoms of flu
The symptoms of flu usually develop within 1 to 3 days of becoming infected. Most people will feel better within a week.
However, you may have a lingering cough and still feel very tired for a further couple of weeks.
Flu can give you any of the following symptoms:
- a sudden fever – a temperature of 38C (100.4F) or above
- a dry, chesty cough
- a headache
- tiredness and weakness
- aching muscles
- limb or joint pain
- diarrhoea or abdominal (tummy) pain
- nausea and vomiting
- a sore throat
- a runny or blocked nose
- loss of appetite
- difficulty sleeping
Is it flu or a cold?
It can sometimes be difficult to tell if you have flu or just a cold, as the symptoms can be quite similar. The main differences are:
- come on quickly
- usually include fever and aching muscles
- make you feel too unwell to continue your usual activities
- come on gradually
- mainly affect your nose and throat
- are fairly mild, so you can still get around and are usually well enough to go to work
When to visit your GP
If you are otherwise fit and healthy, there's usually no need to visit your GP if you have flu-like symptoms.
You should just rest at home until you feel better, while keeping warm, drinking plenty of water and taking painkillers if necessary.
Read more about how to treat flu
Consider visiting your GP if:
- you're 65 years of age or over
- you're pregnant
- you have a long-term medical condition – such as diabetes, heart disease, lung disease, kidney disease or a neurological disease
- you have a weakened immune system – for example, because you're having chemotherapy or have HIV
- you develop chest pain, shortness of breath or difficulty breathing, or start coughing up blood
- your symptoms are getting worse over time or haven't improved after a week
In these situations, you may need extra treatment to prevent or treat complications of flu.
“If someone develops fever post vaccination, this should usually resolve within 48 hours. This is a relatively common, expected reaction, and self-isolation and testing for COVID-19 are not required unless COVID is suspected based on other clinical criteria such as cough and/or anosmia.
If fever persists beyond 48 hours or an individual develops other COVID-19 related symptoms, then they should self-isolate and be recommended to have a test for COVID-19. Testing for COVID-19 may also be considered at any time following clinical assessment, or if there are other epidemiological indications such as being a close contact of a case or part of a cluster.”