Flu and influenza-like illnesses

Sometimes also known as ILI (influenza-like illnesses)

The flu (influenza) is a viral infection. Most people recover within a week or two, but it can cause serious illness in some people. Vaccination is your best protection.

Could it be COVID-19?

Symptoms of COVID-19 are similar to having a cold or the flu.

Symptoms of COVID-19 can include:

  • a cough
  • a high temperature (38˚C or higher)
  • shortness of breath
  • a sore throat
  • sneezing and runny nose
  • fatigue
  • upset stomach, possible with diarrhoea (runny poo) or vomiting (being sick)
  • temporary loss of smell.

If you have any of these symptoms, get tested for COVID-19.  

What are the symptoms of the flu?

Influenza (flu) can sometimes be confused with the common cold, but having the flu is usually much worse than having a cold. Read more about cold vs flu. You can be infectious for about a day before symptoms appear.

You are likely to have a combination of symptoms including:
  • muscle or body aches
  • fever (a temperature of 38°C or higher)
  • chills
  • headache 
  • sore throat
  • cough
  • runny or stuffy nose
  • stomach upset, vomiting, diarrhoea.

Symptoms can last 1–2 weeks, a cough may last longer. It will probably be a few weeks before you feel like you've fully recovered.

Up to 80% of people don’t have symptoms but can still pass their flu on to other people. If you do get symptoms, they can come on suddenly and usually mean you are too sick to work, play sport or take planned holidays.

Image: Canva

How can I look after myself if I have the flu?

Self-care

The best thing you can do is rest at home until you feel better. Stay home from work or school and away from other people while you are unwell. Other things you can do are to:

  • keep hydrated to replace fluids you lose because of fever and sweating
  • drink mainly water and avoid tea, coffee and alcohol as they dry you out even more
  • sip fresh lemon juice mixed with honey and hot water or gargle salt water to soothe a sore throat or dry cough
  • eat only light food when you are hungry 
  • use a damp cloth to cool your forehead and limbs
  • shower or bathe regularly and keep bedding clean and dry.

Medication

Influenza is caused by a virus so antibiotics do not help.

Take paracetamol or ibuprofen to help relieve fever, body aches and headache. Lozenges or gargles may ease symptoms such as sore throat, runny nose and cough. Ask your pharmacist for product advice for young children. Most cold and flu medicines aren't suitable for children under 6 years. Don't give aspirin to children under 16 years.

Please phone your pharmacy rather than going there when you are sick. Consider asking someone to collect your medicines or have them delivered.


When to seek urgent medical advice

If you have:

  • a high fever that doesn’t come down, especially if you are pregnant
  • chills or severe shaking
  • difficulty breathing or chest pain
  • purple or bluish discolouration of lips, skin, fingers or toes
  • seizures or convulsions
  • signs of other serious conditions, such as meningococcal disease
  • signs of dehydration such as dizziness when standing, and not passing wee/mimi regularly.

If your baby or child: 

  • is breathing fast or noisily or if they are wheezing or grunting
  • is very pale
  • is drowsy or difficult to wake
  • is severely irritable, not wanting to be held
  • is limp or unable to move
  • has dry nappies or no tears when they are crying, which means they are dehydrated
  • has signs of other serious conditions, such as meningococcal disease.

If you're not sure what to do call Healthline 0800 611 116 or your nurse or doctor for advice. Many services offer a telehealth service where you can have a consultation over the phone or via video.

What causes the flu?

 
(The Immunisation Advisory Centre, NZ, 2017)


Influenza is caused by the influenza virus. It is common and around 1 in 4 New Zealanders are infected with influenza each year.

You can catch the flu by breathing in virus-containing droplets that have been talked, sneezed, coughed or laughed into the air by a person with the flu. You can also catch the flu by touching your mouth, nose or eyes after touching something that the infected droplets have recently landed on. The virus can survive outside the body on hard surfaces for up to a week, although will usually die within 24 hours.

The strains of virus that cause influenza constantly change, so having had the flu before does not stop you getting it again. The best way to protect against getting the flu is to have an annual flu vaccination. Each year, the formulation of the flu vaccine is reviewed and updated to keep up with changing flu viruses.

What complications can the flu cause?

Most people who get the flu recover fully, but for some it can cause medical complications which can lead to serious illness. These may include sinus infection, ear infection, bronchitis, pneumonia, heart failure, worsening asthma and miscarriage.

Who is at risk of complications?

People at higher risk of developing complications if they get influenza include:

  • pregnant women and women who have just given birth
  • people with an ongoing health condition (eg, asthma, diabetes, cancer, a heart or lung condition, and conditions that affect the nervous or immune systems)
  • very overweight people
  • people aged 65 years or over (for Māori communities and Pacific people the risk is for those aged 55 and over)
  • very young children, especially babies/pēpi under 1 year old.

If you are at higher risk, or are concerned about your symptoms, please contact your doctor or Healthline (0800 611 116). 

Is the flu the same as COVID-19?

Influenza (the flu) and COVID-19 are both contagious respiratory illnesses, meaning they affect your lungs and breathing and can be spread to others. Although the symptoms of COVID-19 and the flu can look similar, the two illnesses are caused by different viruses. The flu is caused by the influenza virus and COVID-19 is caused by the coronavirus.

How can I prevent spreading the flu?

Stay at home 

Stay at home to avoid spreading the virus. Please phone your GP rather than turning up when you are sick, so they can take precautions to protect their staff and other patients. You may be offered a phone or virtual appointment. If you work, take a sick day. It’s best to rest and avoid spreading the virus.

Get a flu vaccination

The influenza vaccination is your best protection against influenza. It is available annually each autumn. The vaccine is slightly different each year, to cover the most common flu strains expected that winter. It is most important for young children, older adults and people who have long-term health problems to be vaccinated. However, everyone should consider getting a vaccine to reduce the spread of flu in the community. Read more about why vaccinate?

(Ministry of Health, NZ, 2013)

Wash your hands

  • Wash your hands often, preferably with soap and water for at least 20 seconds and dry them, or use an alcohol-based hand sanitiser.
  • Wash your hands especially before preparing food or eating, after going to the toilet and after tending to sick people.
  • Also, wash your hands after returning from the supermarket or communal areas like malls, and after coughing, sneezing or blowing your nose, wiping children’s noses, or if you have touched soiled tissues.

Practice good hygiene

  • Try not to touch your nose, mouth, ears or eyes as the flu virus can enter your body this way.
  • Clean surfaces around the house more often if someone is sick, such as door handles, phones and bathroom surfaces, as flu viruses can live on these.
  • Don’t share glasses, drink bottles or cutlery, and wash dishes thoroughly.
  • Cover your mouth and nose with a disposable tissue when you sneeze or cough, or sneeze or cough into your elbow.
  • Use disposable tissues not cloth handkerchiefs for blowing your nose.
  • Dispose of used tissues straightaway in a plastic bag or lined bin with a lid (preferably one you don’t need to touch, such as a pedal bin).

Keep your distance and wear a mask

  • If someone is sneezing and coughing, try to keep 1 metre or more away from them.
  • Wear a mask to avoid spreading the virus.
  • Try to avoid being in large groups of people or crowded places during flu season.
  • Prevent flu spreading by you or anyone else sick staying at home and away from visitors.
  • Try to keep other members of the household away from a sick family member, eg, have them sleep in a separate room, if possible.

Learn more

The following links provide further information about influenza. Be aware that websites from other countries may have information that differs from New Zealand recommendations.   

Flu (influenza) vaccines Ministry of Health, NZ
Flu teaching resource for children
 Autism Speaks, NZ

References

  1. Influenza The Immunisation Advisory Centre & Ministry of Health, NZ, 2020
  2. Influenza Ministry of Health, NZ, 2022

Information for healthcare providers

Influenza information for health professionalsThe Immunisation Advisory Centre and Ministry of Health, NZ
Decision to widen access to influenza vaccine PHARMAC, NZ, 2022

Reviewed by

Dr Sharon Leitch is a general practitioner and Senior Lecturer in the Department of General Practice and Rural Health at the University of Otago. Her area of research is patient safety in primary care and safe medicine use.
Credits: Health Navigator Editorial Team. Reviewed By: Dr Sharon Leitch, GP and Senior Lecturer, University of Otago Last reviewed: 27 Jun 2022