Influenza is a viral infection of your nose, throat and sometimes your lungs. It spreads quickly from person to person through touch and the air. Most people who get the flu recover within a week or two, but it can cause serious illness in some people. Vaccination is your best protection.
Influenza (flu) can sometimes be confused with the common cold, but having the flu is usually much worse than having a cold. Symptoms come on suddenly and you will normally need to rest in bed.
Influenza can occasionally cause serious complications and death in young children, elderly people, pregnant women or people with long-term health conditions.
Flu is very infectious and easily spread to other people. Around 1 in 4 New Zealanders are infected with influenza each year.Of these, up to 80% may have no symptoms, yet are able to pass it on to other people.
Your best protection is to have a flu vaccination each year.
Influenza is caused by a virus, so antibiotics do not help treat the flu. However, there are other things you can do to help relieve your symptoms.
See a doctor immediately:
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
If you are unsure what to do call Healthline 0800 611 116 or your doctor for advice.
What causes the flu?
Influenza is caused by a virus. 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 theflu vaccineis reviewed and updated to keep up with changingflu viruses.
What are the symptoms of the flu?
The symptoms of the flu come on suddenly and usually mean you are too sick to work, play sport or take planned holidays.
You are likely to have a combination of symptoms including:
muscle or body aches
fever (a temperature of 38°C or higher)
runny or stuffy nose
stomach upset, vomiting, diarrhoea.
Symptoms can last 1 to 2 weeks. A cough may last longer. It will probably be a few weeks before you feel like you've fully recovered.
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 (like 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
very young children, especially babies under 1 year.
What is the treatment for the flu?
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
inhale hot steam to clear your sinuses
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.
Influenza is caused by a virus so antibiotics do not help.
Take paracetamol or ibuprofen to help relieve fever, body aches and headache. Ask your pharmacist about other medicines such as lozenges or gargles to ease symptoms such as sore throat, runny nose and coughs. Be aware that most medicines for flu, coughs and colds contain ingredients that are not recommended for children under 6 years. Ask your pharmacist for product advice for young children and do not give aspirin to children under 16 years.
Antiviral medicines are available that treat the flu infection. These are:
These medicines must be taken within 48 hours of your symptoms first appearing or they are unlikely to shorten your illness. They are usually only recommended if you are at high risk of complications of your flu infection, such as pneumonia (lung infection).
Antiviral medicines do not cure flu or offer long-term protection against flu. The best protection against the flu is getting the flu vaccine every year. If you do not have an antiviral medicine you are still likely to make a full recovery. GPs are only allowed to prescribe an antiviral medicine when national surveillance schemes show there is a lot of flu in the community. An antiviral medicine is also often used if you are admitted to hospital with flu. It may also be prescribed to some people to prevent flu, eg, if you live in a residential home and there is an outbreak of flu in the home. It is also given if you are at increased risk of complications of flu and have been in close contact with a person with flu.
See your doctor
See your doctor if you have not improved after 4 days, or if you are elderly or have other long-term health conditions. Young children with flu also need to be seen by their doctor. To avoid spreading flu virus, phone your doctor or health clinic before turning up.
How can I prevent spreading the flu?
Get a flu vaccination
The influenza vaccination is your best protection against influenza. Each year it is made available in the autumn 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, it is worth everyone getting a flu vaccination as when enough people in the community are vaccinated, the spread of a disease slows down or stops completely. Read more about why vaccinate?
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
If someone is sneezing and coughing, try to keep 1 metre or more away from them.
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.
The following links provide further information about influenza. Be aware that websites from other countries may have information that differs from New Zealand recommendations.
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
Last reviewed: 06 Aug 2018
What are the benefits of the influenza vaccination?
Having an influenza vaccination (flu shot) is the best way to protect against getting the flu.
You will have fewer days away from work or school. A flu vaccination programme carried out in 1997–1998 reduced the number of flu cases that resulted in sick leave by 82%.
You won’t miss out on social, cultural or religious events or holidays.
You will help protect vulnerable people in your community, such as very young children, elderly people and people with long-term health conditions.
If you do get the flu despite having a vaccination, you are likely to be not as sick.
How well does the influenza vaccine work?
The flu vaccine is not 100 per cent effective. However, it on average halves the number of people who get the flu. This has a significant effect on the amount of flu circulating in the community, as well as on healthcare services.
Those who respond least well to the flu vaccine are those who are at most risk of complications from the flu – very young children, elderly people and people with long-term health conditions. This is why it’s a good idea for everyone else to get the flu vaccination – it’s a way to help the more vulnerable members of our community.
Dr Nikki Turner explains more about the effectiveness of the influenza vaccine.
(Immunisation Advisory Centre, 2016)
Where can I get vaccinated against the flu?
You can get the flu vaccine by making a single visit to your doctor or practice nurse. You may also be able to get the flu vaccine from some community pharmacies.
The influenza vaccine may be available through your workplace
If you live or work with people more likely to have complications as a result of influenza or if you work in an essential service (eg, police, hospital workers, teachers, etc), ask your doctor or practice nurse about getting vaccinated.
Some workplaces will arrange for flu vaccination for employees each year before the onset of winter. Check whether yours is one of them.
It takes two weeks after vaccination for the vaccine to be fully effective.
You may develop influenza in this time if you come into contact with the virus, so get your flu shot before winter.
Each year the flu vaccine is developed to match the different strains of flu virus that is likely to be in New Zealand. The new vaccine is usually made available in early March. Get your vaccination before winter when the flu is most prevalent.
Occasionally the vaccine strains are the same for more than one year, but it is still recommended that you have the vaccine each year, as the protection provided by the vaccine lessens over time.
Vaccination is free for some groups
From early March each year (for a specified period), immunisation is free for New Zealanders who are:
65 years and over
under 65 who have certain medical conditions
children aged 4 years or under who have been hospitalised for respiratory illness or have a history of significant respiratory illness
The vaccine cannot cause influenza because it does not contain any live viruses. Rather it contains a less virulent strain of the virus which is capable of stimulating an immune response and creating immunity but not causing the illness. Most people generally tolerate the vaccine well.
Any after-effects from the vaccine are usually mild and last a day or two, eg:
soreness, aching and/or redness at the injection site
tiredness, feeling a little unwell or having a mild fever.
These after-effects are signs your immune system is working with the vaccine. It is important to let your doctor know if you have any more severe reaction to the flu vaccination, or if you are at all concerned.
Do I need the flu shot if I am travelling?
Whether or not you are at high risk for the complications of flu, you should consider getting a flu vaccination before travelling overseas because you may be some distance from medications and medical care of the standard you are used to.
Also, the flu season varies around the world. A relatively inexpensive flu vaccination before you go can reduce the effects of catching flu while away and help to avoid spoiling your trip.
The following information is taken from the discussion document for consideration of the best time to start the Annual Influenza Immunisation Programme from the Ministry of Health.
Background information about influenza
Influenza can cause severe illness and secondary complications can lead to hospitalisation and death in high risk groups, including young children, older people, pregnant women and those with a range of underlying medical conditions. However, sometimes even healthy children and adults can also be at risk of serious illness following influenza infection. Māori and Pacific people and those from lower income groups experience a higher burden of disease from influenza. On average, approximately 400 deaths are attributed to influenza and its complications annually.
Each year, seasonal influenza impacts on population health and the health system, causing increased demand for health services, including general practice visits and hospitalisations, especially for those at greater risk from the complications from influenza.
The impact of influenza in New Zealand is substantial on the health of the population and health sector. The highest burden of disease is in the very young, older people, pregnant women, those with underlying medical conditions, people from low income groups, and Māori and Pacific peoples.
The influenza vaccination is the most effective preventative measure to protect those at risk from influenza and its complications. Influenza vaccination prevents the spread of disease, reducing the chance of passing on the influenza virus to those in high risk groups.
Factors that impact on vaccine effectiveness (VE)
VE is affected by the influenza vaccine’s match to circulating influenza virus strains, vaccine characteristics, and other host factors such as the individual’s age, underlying medical conditions and time since vaccination. During seasons where the vaccine strains closely matches the circulating strains, VE can be as high as 80 to 90 percent in healthy adults. The World Health Organization (WHO) annually selects the vaccine strains for the Northern and Southern Hemisphere influenza seasons to match the most recent circulating strains.
New Zealand’s Annual Influenza Immunisation Programme
Influenza seasons vary in timing and duration. Surveillance data shows that the New Zealand influenza season typically runs from May to September and peaks around July (refer to Figure 1). However, in recent years the peak has moved to August, which was the rationale for extending the end of the funded Programme until 31 December each year.
Based on current surveillance data, the shift in peak influenza activity and the decline in VE support a change to the timing of the start of the Programme, for example to early April.
Influenza programmes need to start before the onset of the influenza season, and the vaccine takes up to two weeks to become effective. Any change to the Programme’s start date will need to be considered alongside the implications for service delivery. Status Quo
The Programme traditionally started in late February/early March and continued to 31 July. In recent years the Programme has been extended due to the influenza peak not being reached until late July/August. From 2017 onwards, the Programme end date was moved to 31 December to ensure high risk groups, especially pregnant women or those who were not vaccinated earlier in the year, continue to have access to protection against influenza even as activity decreases. There have been years where the Programme has started late due to a delay in vaccine manufacture associated with a strain change. In 2018, the Programme did not start until early April and in 2015, the Programme started 26 March. Delays in vaccine manufacture associated with a strain change cannot be predicted.
Seasonal influenza promotional campaigns 2017 and 2018
(Barbara McArdle, 2018)
Update on New Zealand influenza and vaccination strategy
Ministry of Health. Immunisation Handbook 2017(2nded). Wellington: Ministry of Health; 2018, 279 p. [pdf]
Centers for Disease Control and Prevention. Prevention and control of seasonal influenza with vaccines: Recommendations of the Advisory Committee on Immunization Practices – United States, 2016–17 influenza season. Morbidity and Mortality Weekly Report: Recommendations and Reports 65(RR05) [Internet]. 2016. [cited 2018 May 15]. Available from https://www.cdc.gov/mmwr/volumes/65/rr/rr6505a1.htm
Ministry of Health. Discussion document for consideration on the best time to start the Annual Influenza Immunisation Programme. Wellington: Ministry of Health; 2018