Seasonal influenza is caused by any of 4 types of influenza viruses - A, B, C and D - which circulate around the globe; the acute respiratory infections they produce are more likely to occur during the cold seasons in the northern and southern hemispheres, but year-round in the tropics.
It’s important to stress that influenza is different to other common viral respiratory infections; it may be life-threatening for some people so it should not be confused with the common cold! Due to the risk of complications, the National Immunisation Program now funds flu vaccination in pregnancy, for children 6 months to under 5 years, people 6 months and over with specified medical risk conditions, and seniors 65 years and over.
Influenza Infections & Outbreaks
In most parts of Australia our annual outbreaks tend to occur between late autumn and early spring, although there may be cases early in the year which are often sparked by returning travellers.
Between 5 and 20% of our population may be infected each year depending on the extent of the outbreak - from mild sporadic outbreaks to serious epidemics.
Occasionally severe worldwide outbreaks (pandemics) occur involving very high infection rates and more severe disease. The outcomes of these outbreaks can be devastating, resulting in between 3 and 5 million cases of severe illness, and about 290,000 to 650,000 respiratory deaths.
What is Influenza?
Influenza A and B viruses are the major culprits in causing flu-related human upper respiratory disease, and the illnesses they produce can range from mild to severe and even result in death. The most common symptoms of seasonal influenza are of sudden onset and include fever, cough (usually dry), headache, muscle and joint pain, severe malaise (feeling unwell), sore throat and a runny nose. The cough can be severe and can last 2 or more weeks. Antibiotics are ineffective against the influenza virus but may be used if a secondary bacterial infection occurs.
Where is it found?
Epidemics of influenza occur during the winter and spring months in most years. The virus causes disease in all age groups, but while rates of infection are highest among children, serious illness and death is more common with the elderly and persons of any age who have medical conditions that place them at high risk for complications. Flu viruses can also cause global epidemics of disease, or pandemics, during which rates of severe illness and death from influenza-related complications can increase dramatically.
How Do Flu Vaccines Work?
Flu vaccines offer a high degree of protection against seasonal illness and severe consequences, however they need to be administered annually due to the constant changes in the influenza viruses. About 2 weeks after having the flu vaccine antibodies develop in the body to protect against disease. These antibodies provide protection against infection from the viruses that the vaccine is produced to target. It protects against the four influenza viruses that research indicates will be most common during the upcoming season.
Flu Vaccine Benefits
Flu vaccination can reduce the risk of flu-associated hospitalisation for children, working age adults and older adults and it prevents tens of thousands of these hospital admissions each year. In 2019 there were more than 310,000 laboratory-confirmed flu notifications by the beginning of December and by October 6, more than 800 influenza-associated deaths.
Who Needs Influenza Vaccinations?
Flu vaccination is an important preventive tool for people with medical conditions that increase their risk of influenza, women who are pregnant or breastfeeding, Aboriginal and Torres Strait Islander people, infants and children ≥5 years of age, adults ≥65 years, certain occupational groups and travellers. Employers offer workplace flu vaccinations as they have been shown to reduce absenteeism and increase productivity.
The flu vaccine is recommended for all babies ≥6 months of age and over annually. It’s now also funded for the ≥6 months to 5 years age group. A study by the US Centers for Disease Control and Prevention (CDC) in 2017 was the first of its kind to show that flu vaccines for babies can significantly reduce a child’s risk of dying from flu.
Flu vaccines during pregnancy reduce the risk of flu-associated acute respiratory infection in these women by about one-half. In fact one study conducted in 2018 found that getting a flu vaccine while pregnant reduced a woman’s risk of being hospitalised with flu by an average of 40 percent.
An additional benefit is also passed on to the baby: A number of other studies have shown that a flu vaccine given during pregnancy helps protect the baby from flu for several months after birth, when he or she is not old enough to be vaccinated.
Seniors & The Elderly
Adults aged ≥65 years are strongly recommended to receive an annual dose of influenza vaccine.
The recommended flu vaccine for those aged 65 years and older is the adjuvanted influenza vaccine which is preferable to the formulation given to younger people as it offers enhanced protection against a flu strain which is more likely to cause severe illness in the ≥65 years.
Influenza-associated mortality rates are highest among adults aged ≥65 years but flu vaccines for seniors have been shown to reduce hospitalisations from influenza and pneumonia, and all-cause mortality.
When You’re Sick or Ill
Best advice if you are sick with the flu is to stay home, rest, drink plenty of fluids, treat the fever and any associated symptoms such as cough, and don’t pass it on to others. If you have any symptoms that are worrying you, contact your doctor. Once you’ve recovered, if you haven’t had a yearly flu vaccine, you should consider getting one. It protects against four virus strains so it can help prevent you getting a second dose of the flu. It’s not advisable to have a flu vaccine when sick (acute illness with fever ≥38.5°C), so speak to your doctor about the best time to get it.
In order to create a protective herd immunity and reduce absenteeism/presenteeism in the office, it is recommended for all healthy, younger individuals and employees to have workplace flu vaccinations.
Risk to travellers
The risk for exposure to influenza during travel to foreign countries varies depending on the time of year and destination: In the tropics, influenza can occur throughout the year; in the southern hemisphere, most activity occurs from April through September, while in the northern hemisphere peak activity occurs from November through March. Remember though, that the people sharing your aircraft cabin, cruise ship, train, bus or stadium may have come from a region with high flu rates, which puts you at risk of infection.
In recent years, influenza strains originating in birds (avian influenza) have sickened humans in various parts of the globe including China, Indonesia and Egypt. Fortunately, transmission of these viruses between humans has been rare to date, however the possibility of a mutation of the viruses allowing for further spread remains. Advice for travellers to areas affected by avian influenza outbreaks includes: avoid animal markets, don’t touch animals/birds, eat only well-cooked chicken & eggs and practice good personal hygiene. Recommendations for travellers to countries experiencing avian influenza outbreaks can be found at Australian Department of Health.
Travelvax recommends vaccination against influenza be considered for anyone over 6 months of age, but particularly if they:
- are over 65 years of age.
- have a chronic heart or lung condition.
- are pregnant
- are travelling with large tourist groups (particularly trains, buses, cruise ships)
- are a business traveller wishing to avoid lost time
- are cruising
- will be participating in mass gatherings
- want to avoid getting (and spreading) this vaccine-preventable illness
NB - Vaccination is recommended every 12 months. If travelling to a different hemisphere, the types or strains of flu virus circulating may differ from the hemisphere from which you have travelled. If you have been vaccinated recently against influenza, it is advisable to check if the strain of the virus at your destination is covered by the vaccine you have received.
- Single dose annually - adult and child formulations.
- For infants & children aged 6 months to 10 years who have never had the vaccine before: 2 doses at least 4 weeks apart in the first year.
- Single dose annually of high dose or adjuvanted quadrivalent vaccines for people aged 65 years and over
Contraindications: People who have previously had an allergic reaction following an influenza vaccine or component of an influenza vaccine.
Those individuals with known anaphylactic hypersensitivity reactions to egg proteins (eggs or egg products) or chicken proteins should discuss with a doctor whether administration of this vaccine may be conducted under special conditions (as per the Australian Immunisation Handbook). Otherwise a new formulation is being introduced which is not produced using eggs.
Level of protection
6 to 9 months protection against forecast influenza viruses each season. (Will not protect against the common cold viruses or COVID-19.)
Possible Side Effects
- Usually infrequent and mild
- Soreness at the injection site in around 10% of vaccinees
- 15- 20% may experience fever, lethargy and muscle aches
- High dose or adjuvanted trivalent vaccines produce injection site reactions in around 30% of vaccinees.
NB: Contrary to popular myth, none of the influenza vaccines are live so cannot cause influenza.
As with all vaccines, there is a small risk of allergic reaction.
Where Can I Get a Flu Vaccination Near Me?
If you require vaccination against influenza head to a Travelvax clinic nearby. Staffed by health professionals who have access to state-of-the-art equipment, we can help keep you safe throughout the current season and beyond.