Common symptoms of influenza are;
Complications of influenza may include;
A respiratory illness associated with infection by the influenza virus. Influenza is different from a cold, mainly because the symptoms and complications are more severe. Most people have some immunity, and a vaccine is available. The elderly and infirm often die from seasonal influenza, while in young adults it is rarely fatal.
Seasonal influenza is a contagious respiratory illness caused by common influenza viruses. Most people have some immunity, and a vaccine is available.
Influenza makes people feel worse than an ordinary cold. For most people influenza infection is just a nasty experience, but for some it can lead to illnesses that are more serious. These illnesses may require treatment in hospital and can be life threatening especially in the elderly, asthmatics and those in poor health.
The most common symptoms of influenza are an abrupt onset of fever, shivering, headache, cough, sore throat and aching muscles & joints. Most people confuse influenza with a heavy cold, however influenza is usually a more severe illness than the common cold, which is caused by other respiratory viruses.
Cold symptoms are limited to the upper respiratory tract with runny nose, sneezing, watery eyes and throat irritation. The symptoms usually occur gradually and do not cause a fever or body aches.
Influenza occurs most often in the winter months and usually peaks between June and August in the southern hemisphere. Illnesses resembling influenza may occur in the summer months but they are usually due to other viruses.
The flu virus is highly contagious and is easily passed on by breathing in the tiny droplets from the breath of infected people. The incubation period - delay between infection and the appearance of symptoms - is about 1-2 days. The infectious period varies but an infected person can probably pass on the disease the day before their symptoms appear and remain potentially infectious for 3-8 days.
Children have a greater risk of being infected because they have not developed immunity to the virus. The elderly have a greater risk of the severe complications of infection such as pneumonia, because they often have underlying diseases, which reduce their resistance to infection. It is strongly recommended that immunisation be offered to all health care workers and those living & working in close proximity to each other (i.e., the military).
Routine vaccination offers the best protection and people who are at high risk of infection should be vaccinated. It is difficult to avoid infection if there is an epidemic. Keeping away from crowded places can reduce the risk of becoming infected and spreading it to others. A previous flu infection or vaccination will not necessarily provide protection against further infections because the virus is continually changing genetically and different subtypes circulate each winter.
The virus is constantly changing with new strains and variants constantly emerging. People develop immunity either as a result of becoming infected, or through vaccination. As immunity is specific to individual strains of the virus, the emergence of a new strain will mean that people will contract the disease and a new vaccine will need to be developed. Each year one or two subtypes of influenza A may be in circulation and one type of influenza B.
Flu vaccinations are 70-80% effective in healthy adults, in years when there is a good match between the vaccine and the strains of flu in circulation. In recent years we have been getting better at predicting the strains which are likely to circulate, and in most years there is now a good match between the vaccine and the circulating strains. Most people who have been vaccinated don't get the kinds of flu from which the vaccine was made. If you do catch flu it is likely to be milder than if you had not been vaccinated.
Flu vaccines are very safe. They may cause some soreness where you were injected and, less often, a slight temperature and aching muscles for a couple of days. Common side effects of influenza vaccine include soreness & redness at the injection site and mild fever, fatigue & muscle soreness. Rarely, a person may develop an allergic reaction such as an itch or red rash, experience difficulty in breathing and have general swelling.
You should not be vaccinated if you have a serious allergy to chicken eggs; have had a previous severe reaction to the influenza vaccine or have previously had Guillain - Barré Syndrome.
Whilst it is impossible to predict, there is the possibility that being vaccinated with the seasonal vaccine may provide some limited protection against pandemic influenza strains.
No. The vaccine will not protect against pandemic influenzas such as Avian influenza
The best time to be vaccinated is between late March and early April (but useful any time during the influenza season) ready for the winter. You shouldn't wait until there is a flu epidemic.
No. The vaccine requires 2 weeks for protection to develop.
If you feel you need a flu vaccination, check with your Medical Officer.
5 December, 2011