Flu – how long it lasts, symptoms and self-care tips

28th October, 2022 • 15 min read

Flu is a virus that attacks your nose, throat, and lungs. And even if it’s mild, it can leave you feeling really sick.

Although it usually gets better on its own, flu can make you too unwell to get on with your daily life for a while – some people say it feels like they’ve been hit by a truck. And for certain people, it can cause complications that lead to serious illness.

‘Because flu has many of the same symptoms as

, it can be tricky to know what you have, and to get the right treatment,’ says Dr Ann Nainan, family doctor and Healthily expert. ‘But while you won’t always be able to avoid catching the flu, there are proven things you can do to feel better and help you recover.’

When is flu season?

Flu season varies, and may last longer or be more severe in one year than another. But the virus is more common in colder months. In countries in the Northern Hemisphere, such as the US, it’s generally between October and March. In Southern Hemisphere countries such as Australia, meanwhile, it’s typically between April and September.

In other words, wherever there is winter, there is flu (although you can also get flu in more tropical countries). The flu virus survives best in colder, drier temperatures. Plus, during winter, we spend more time indoors with the windows shut, so we’re more likely to breathe the same air as someone who has flu.

‘In the US, the number of cases often peaks in February, while in the UK it’s between December and March,’ says Dr Ann. ‘This means any prevention, like getting your flu shot, should happen in early fall to help cut your risk.’

To find our more about how to look after yourself during flu season, check out our

guide to winter health

What exactly is flu, and what causes it?

Flu is the common name we use for influenza, a viral infection that’s spread easily between people (contagious) and affects your nose, throat and lungs (respiratory system).

The flu virus enters a healthy cell in your body, which it infects, and then it multiplies. These new viruses then infect other cells, and your body becomes a battleground – your immune system versus the virus.

If your immune system wins, you won’t get sick. But if the virus wins, it causes an ‘inflammatory response’ – your body’s defense against flu, and also what causes symptoms.

What are the symptoms of flu?

Flu symptoms can be nasty and leave you feeling really sick. Unlike with a cold, they often come on quickly and can include:

  • a sudden high temperature (fever), or feeling feverish/chills (though you can also have flu without fever)
  • muscle or body aches
  • a dry cough
  • a sore throat
  • a runny or blocked nose
  • headaches and eye pain
  • feeling very tired (fatigue) and not wanting to get out of bed
  • not wanting to eat (loss of appetite)

Tummy symptoms, such as being sick (vomiting) and loose poops (diarrhea) are less typical. Though they’re more common in children, and certain ‘strains’ of flu can be more likely to cause them.

How long do flu symptoms last?

Symptoms of flu can come on very quickly and last anything from a few days to 2 weeks, or sometimes even longer.

Some people also get complications from having flu, which means they will feel sick for longer (see


What are the stages of flu recovery?

Flu will often follow this pattern:

Days 1-3: You get a sudden fever, headache, muscle pain, tiredness and weakness, a dry cough, sore throat, and sometimes a blocked or runny nose.

Day 4: Your fever and muscle aches start to ease. But a hoarse, dry or sore throat, cough and possible mild chest discomfort become more noticeable. You may feel tired or flat.

Day 8: Your symptoms usually start to go away – although the cough and tiredness may last for 1 to 2 more weeks.

What other women say about flu

‘I had no energy at all – if I tried to move, I’d feel so tired that I’d have to lie down again. The worst part was that my taste buds completely went – for about a week, eating was like chewing cardboard.’
Jo Wheatley, 41

‘I’ve had flu and COVID-19. Flu was much worse. Every part of my body ached, I had high temperature and I was completely wiped out. I felt sick and exhausted. For me, it was much more intense than COVID-19, which seemed to come and go.’
Fiona Bugler, 49

‘I was worried about getting the flu shot when I was pregnant; I thought it might harm my baby. But my midwife explained that pregnant women and new mums can get changes in their immune system, heart and lungs, so are more likely to get seriously ill from flu. That was enough to convince me that it was the right thing to do.’
Hazel Wood, 33

How does flu spread?

Flu is common because it’s very easy to catch (contagious). Here’s what you need to know:

  • it passes from an infected person in droplets from coughs and sneezes, which contain the virus
  • infected droplets can linger in the air, or live on surfaces for about 24 hours
  • you can catch flu if you breathe in infected droplets, or touch a surface with them on and then touch your face

What is the incubation period for flu?

Flu symptoms will usually show up about 2 days after you come into contact with the virus – although it sometimes takes up to 4 days to start feeling sick. This period of time is known as the ‘incubation period’.

How long is the flu contagious?

You can be contagious from about 1 day before your symptoms appear, and for about 5 days to a week afterwards. Children and people with weakened immune systems may be contagious for longer than this.

Because you won’t know straight away if you have flu, you can unknowingly pass it on. Plus, nearly 30% of people carrying the flu virus don’t get any symptoms.

Can you get the flu twice?

Yes. Like colds, flu is caused by lots of different viruses, so you can get infected by different types, or ‘strains’.

If your body hasn’t built up immunity to a particular strain, flu symptoms are your immune system’s response to it.

Flu viruses are constantly changing, with new strains appearing every year.

How many people get flu?

In the US, an estimated 36 million people had flu during the 2019-2020 season. On average, about 8% of the US population gets sick each flu season.

Who’s most likely to get flu or flu complications?

You’re more likely to get flu if:

  • you’re 65 or older, or a child between 6 months and 5 years old
  • you live or work in places with lots of other people, such as nursing homes or schools
  • you’re staying in hospital

You’re more likely to get complications from flu, such as

(see below(/health-library/conditions/flu/#what-your-doctor-can-do-to-help-with-flu)), if:

  • you’re 65 or older, or a child under 2
  • you have a weakened immune system – such as due to cancer treatment, an organ transplant,
    or long-term use of
    steroid tablets
  • you have a long-term (chronic) health condition – including asthma,
    heart disease
    , neurological and metabolic disorders and
    or blood disease
  • you’re pregnant – especially if you’re in the second or third trimester, or if it’s less than 2 weeks since you gave birth
  • you’re
    – with a body mass index (BMI) of 40 or over
  • you’re American Indian or Alaska Native
  • you’re under 19 and taking long-term
    or salicylate medication

How to avoid getting flu

To help reduce your risk of catching – and spreading – flu, you can:

  • wash your hands often, using warm water and soap
  • cover your mouth and nose with a tissue when you cough or sneeze
  • throw used tissues in the bin straight away
  • try to stay home and avoid contact with other people if you have a fever or you feel too sick to do your normal activities
  • avoid touching your face
  • clean surfaces regularly
  • avoid crowded places during peak flu season
  • stay away from anyone who has flu-like symptoms

The flu shot cuts your risk of getting flu

Though flu shots aren’t 100% effective, they’re still your best defense against getting flu.

‘Each year, the updated vaccine provides protection from the 4 flu strains scientists expect to be the most common,’ says Dr Ann. ‘The vaccine can cut your risk of getting the flu, as well as reducing how sick you’ll get and your risk of serious complications if you do get it. And remember, you can’t catch flu from the shot.’

Read more about how the flu shot prevents flu and how to get it.

Self-care for flu

Although it can make you feel really unwell, most people recover from flu in a week or 2. Your immune system will fight the infection and you shouldn’t need to see a doctor. But self-care can help you feel less sick while you’re recovering.

Flu home remedies

To help yourself, you can try:

  • getting plenty of rest and sleep
  • drinking lots of water to avoid
  • using a hot water bottle to soothe muscle pain
  • gargling warm water or sucking on sugar-free lollies or lozenges to ease a sore throat
  • inhaling warm, moist air to help unblock your airways
  • clearing a stuffy nose with saline nose drops or spray from a pharmacy
  • taking pharmacy medicines to lower your temperature and ease aches and pains (see

What to eat when you have flu

Unfortunately, there’s no scientific proof that any one food will help you feel better more quickly than another when you have flu. But while you might not feel hungry when you’re sick, it’s important to stay hydrated, and to keep up your energy levels by eating if you can.

Foods that have traditionally been used to help with flu include:

  • chicken soup – everyone’s go-to when they’re feeling sick (especially your grandma). It’s thought that the ingredients commonly used in chicken soup could help fight inflammation
  • foods high in
    vitamin C
    – including peppers, oranges, grapefruit, kiwi fruit and grapes. These could help support your immune system, but whether they help fight flu hasn’t been proven
  • leafy greens – it’s thought that these vegetables may have anti-inflammatory effects, but whether they can help fight flu isn’t known

How your pharmacist can help with flu

Your pharmacist can suggest medicines to ease your symptoms. If you buy medicine from a pharmacist, always check it’s right for you – you should let them know if you’re taking any other medication, or if you’re pregnant or breastfeeding.

What flu medicine can you get from a pharmacy?

Pharmacy medicines can help minimize flu symptoms while your body fights the virus. Your pharmacist may suggest:

  • acetaminophen (
    ) or anti-inflammatory medicines such as
    , to lower your temperature and relieve aches and pains. You shouldn’t take acetaminophen at the same time as flu remedies that contain it, as it's easy to take more than the recommended dose
  • decongestant sprays or tablets, or antihistamines, to ease congestion, a cough and runny nose

What vitamins and herbs help with flu?

Some people swear by supplements such as vitamin C, zinc, echinacea or garlic to help speed up flu recovery. However, there’s little evidence that they work, and most research about them has been done on their effects on the common cold rather than flu.

Your pharmacist may sell these products, and be able to help you choose one that you want to try. Be aware that some herbal medications – such as echinacea – can interact with other medicines, and may also have side effects.

When to see a doctor

Flu will usually get better by itself, but antivirals can shorten the time you’re unwell and help avoid complications if you’re at

high risk
. So if you’re at higher risk, it’s best to see your doctor as soon as flu symptoms start.

If you’ve had symptoms for less than 48 hours, you can also see a doctor to discuss if antivirals would be helpful – but most people don’t need to take antivirals if they’re not in a higher-risk group.

You should see a doctor straight away if you or your child has flu symptoms and:

  • trouble breathing or shortness of breath
  • persistent chest or tummy pain
  • dizziness, confusion or drowsiness
  • seizures
  • hasn’t been for a pee all day
  • severe weakness or muscle pain
  • blue lips
  • a fever or cough that gets better, but then suddenly comes back or gets worse
  • a worsening of any underlying medical condition
  • is coughing up blood

What your doctor can do to help with flu

Prescribing the right medication

Your doctor may prescribe:

  • antivirals – these may reduce how long you’re sick for, and help prevent more serious problems if you’re at higher risk. They’re most effective if they’re started in the first 2 days after symptoms begin, though starting them later can still be helpful for high-risk people. There are several types of medicine available, which can either be taken as a pill or liquid, inhaled as a powder, or given through a drip by a healthcare provider
  • antibiotics – if you get a bacterial infection on top of flu, such as a sinus or ear infection or pneumonia (see below), you may need antibiotics. But these won’t work against the flu virus itself, as they only fight bacteria

Diagnosing and treating complications

If you’re generally healthy, flu isn’t usually serious, but some people will get unwell with complications that need treatment.

The most common complication of flu is pneumonia – swelling (inflammation) in the lungs. Read about

pneumonia treatment

Other possible flu complications include:

How common are flu deaths?

The Centers for Disease Control and Prevention (CDC) estimates that, between 2010 and 2020, flu caused up to 41 million illnesses, 710,000 hospitalizations and 52,000 deaths a year.

Remember, though, it’s rare for otherwise healthy people who aren’t at higher risk of complications to die from flu. According to the CDC, between 70% and 85% of flu-related deaths happen in people over 65 – which is why it’s so important to get your annual flu shot.

Your questions answered by our experts

Is COVID-19 worse than the flu?

"The symptoms of COVID-19 and flu can be similar, and can range from very mild to very severe – both viruses have the potential to make you very sick,’ explains Dr Ann. ‘It’s possible to have flu and COVID-19 at the same time, too. COVID-19 can also cause other complications, such as blood clots, whereas pneumonia is more likely after flu. But for most people with either flu or COVID-19, you can recover at home with rest, fluids and self-care."

3 reasons why you need to get your booster shots

What are the different types of flu?

"There isn’t just one type of flu. In fact, there are 4 types of influenza: A, B, C and D. Viruses A and B are most likely to cause seasonal flu, and type A is the most common, as well as the most extreme. Influenza C causes only mild illness, while influenza D doesn’t affect humans.

Bird flu
is the name given to influenza A strains that spread among birds. Most don’t affect humans, but occasionally a strain can spread to humans and cause a flu outbreak. Stomach flu is another name for the
, also known as the ‘winter vomiting bug’, which causes vomiting and diarrhea."

Does ‘man flu’ exist?

"You’ve probably heard the term ‘man flu’ – it’s used to describe a man who’s exaggerating how sick he really is, or claiming that men suffer much more than women when they’re ill. But is ‘man flu’ real? ‘The concept of “man flu” is usually used in relation to cold viruses,’ says Dr Ann. ‘A common theory for it is that men can take on a “patient role” when they’re ill – seeing their symptoms as worse than they are, so that they can rely on others to look after them. Another possibility is that men actually experience respiratory viral illnesses differently from women. We know women and men get different symptoms with some other conditions – such as heart attacks, for example. However, we can’t say whether this is the case for colds or flu, and there is no evidence yet for either theory."

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.