A cold or the flu? Or COVID-19?

Over the shorter, colder days of winter, it's not uncommon to come down with a cold or the flu. We also now have COVID-19 to be aware of. A cold is usually a mild illness but the flu and COVID-19 can be serious, so it’s good to know the difference.

Key points

  1. Coldsinfluenza (the flu) and COVID-19 all affect your airways and how you breathe. This means they are easily confused with one another. However, a cold is not usually serious, but the flu and COVID-19 can be. 
  2. Colds, the flu and COVID-19 are all caused by viruses. In most people, your immune system will kill the virus, so you can treat mild-to-moderate symptoms at home (or in managed isolation for COVID-19). Antibiotics won’t help as they kill bacteria.
  3. Some people, including young children, elderly people, pregnant women and people with long-term conditions, are at greater risk of complications and may need more treatment.
  4. It’s important to know when to seek medical advice if you or someone you are caring for has flu-like symptoms. If you are high-risk for COVID-19 make sure you get tested
  5. Vaccination is your best defence against the flu. Hand washing and a healthy lifestyle are your best protection against colds. Learn about preventing the spread of COVID-19.

What's the difference between a cold and the flu? 

See also symptoms of COVID-19.

A cold

Influenza (the flu)

Description

  • Mild illness lasting 1–2 weeks.
  • Some symptoms, such as a cough, may continue for a few weeks.

Description

  • Moderate to severe illness with sudden onset of symptoms lasting 7–10 days.
  • The cough and tiredness can last for weeks after the rest of the illness is over.

Symptoms

Early signs include:

  • a sore throat
  • sneezing
  • running nose
  • mild fever.

Even though you may feel tired or have aches, most symptoms are above the neck.

After a few days, snot usually becomes thicker and may turn a greenish or yellowish colour.

Muscle pain is uncommon.

Mild headache (congested sinuses).

Sometimes a cough.

Symptoms

Sudden onset of:

  • fever (usually high, 38–40 degrees Celsius)
  • shivering
  • muscle aches
  • debilitating tiredness
  • headache (may be severe).

Dry cough may become moist.

Bed rest is necessary.

Prevention

Washing your hands frequently.

Not coughing over other people.

Prevention

Influenza (flu) vaccine (free for those in high-risk groups).

Washing your hands frequently.

Not coughing over other people.

Possible complications

Sinus congestion

Ear infection

Possible complications

Bronchitis

Pneumonia – can be life-threatening

Could it be COVID-19?

Symptoms of COVID-19 are similar to a range of other respiratory illnesses that are much more common, such as colds or the flu.

Symptoms of COVID-19 include:

  • a cough
  • a high temperature (at least 38˚C)
  • shortness of breath
  • a sore throat
  • sneezing and runny nose
  • temporary loss of smell.

These symptoms do not necessarily mean you have COVID-19. Difficulty breathing is a sign of possible pneumonia and requires immediate medical attention.

If you have cold or flu symptoms and are high-risk for COVID-19 make sure you get tested for COVID-19.

If you are unsure whether you need to be tested, call your GP or Healthline's dedicated COVID-19 number 0800 358 5453.

When to seek advice for colds or the flu

You can treat most colds and flu-like illnesses with rest and self-care at home, but you need to know when to seek medical help.

Phone your medical clinic for advice if you:

  • are not getting better
  • are pregnant
  • have diabetes or a health condition affecting your breathing, heart or immune system
  • are aged 65 or older
  • have a sore throat and are Māori or Pasifika aged 3–35 years
  • are concerned or not sure what to do.

If you are unsure what to do phone Healthline free on 0800 611 116 or your doctor for advice.

When to seek immediate medical help

If you have any of the following signs you may be seriously unwell and need emergency care: 

  • difficult or painful breathing
  • bluish lips or tongue
  • chest pain
  • coughing up blood
  • severe shaking, rigors
  • confusion or difficult to wake
  • stiff neck
  • rash with purple or red spots or bruises
  • clammy skin
  • not urinating or dark coloured pee.

Phone 111 or go to the hospital emergency department right now. Do not delay.

Self-care for colds and the flu

Rest – at home if possible so you don’t spread bugs.
Drink plenty of water, warm lemon and honey drinks or soups to avoid dehydration (honey is not safe for children under one year).
Sore throat? Suck a teaspoon of honey or gargle salt water. Adults can also try a medicated lozenge, gargle or throat spray.
Blocked or runny nose? Ask your pharmacist about decongestants and nasal sprays.
Cough? Sip a lemon and honey drink or ask your pharmacist about cough lozenges or medicines that may be suitable for you.
Aches and pains? Try paracetamol OR cold and flu medicines (check doses carefully and ask your doctor or pharmacist if safe for you).
Avoid antibiotics – they can’t cure colds, flus or most coughs as these are caused by viruses.

Avoid catching and spreading bugs

Take care of your health and protect your whānau and community.

  • Wash your hands for 20 seconds and dry them well.
  • Cover your coughs and sneezes.
  • Avoid touching your face with unclean hands.
  • Don’t share personal items such as cups, food utensils or towels.
  • Clean and disinfect surfaces often, like doorknobs.
  • Stay home if you are sick and avoid close contact with others.
  • Keep coughs away from other people.

Learn more about preventing the spread of COVID-19.

Keep well this winter

Get the flu vaccine each year – it might be free for you.
Keep your immune system strong – be active, eat healthy food, be smoke-free and get plenty of sleep.
Stay warm – heat your home to at least 18°C.
Quit smoking – smokers get more colds, symptoms are worse and they last longer.

Learn more

Colds Health Navigator, NZ, 2018
Influenza Health Navigator, NZ, 2018
Antibiotic resistance Health Navigator, NZ, 2018

Reviewed by

Dr Sharon Leitch is a general practitioner and clinical research training fellow 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 clinical research training fellow, University of Otago Last reviewed: 25 Feb 2016