Influenza

Influenza is a serious respiratory tract infection that is caused by an Influenza virus. Influenza is very contagious. The disease usually spreads in certain periods of the year, especially winter or early spring. When healthy people catch Influenza, it usually disappears in about one week. In contrast, influenza can cause serious complications and even death. People at risk of these complications are people with asthma and other diseases of the respiratory tract, heart disease, diabetes and elderly people without such underlying disease.

What is the difference between Influenza and the Common Cold?

People often say "I’ve got the flu", when they actually have a common cold. Although a common cold can make you feel pretty bad, and has many symptoms that are similar to Influenza, it is not the same thing. A common cold usually comes on slower. An Influenza infection is characterized by a very swift onset. People go from completely well to very sick in only a few hours. Very high temperatures are common.

A very important difference is that common colds are not harmful to the patients whereas influenza may cause serious complications.

What causes Influenza?

Influenza is caused by the Influenza virus. An Influenza-virus attacks the cells of the respiratory tract and enters it. It then uses the cell’s reproductive system to reproduce itself. Within a very short period, it produces hundreds of new viruses. It takes about an hour for the virus to kill the infected cells. New viruses are released from the cells and these start attacking other cells.

How can I catch Influenza?

You get Influenza from droplets of influenza virus in the air, caused by someone else with Influenza coughing or sneezing. For example, you can catch influenza just by standing next to someone with Influenza on the bus. The virus makes its way down to your respiratory tract and starts attacking the protective cells of the respiratory tract.

How long does it take between infection and getting ill?

The incubation period for influenza is two days. That means that it can take up to two days from catching it, to noticing the first symptoms

What are the symptoms of Influenza?

At first you will suddenly get cold shivers followed by a high fever, sneezing, sore muscles, severe dry cough, headache, sore throat, an overwhelming tiredness and general malaise. The fever and the pain are a reaction of the body to the Influenza virus. People with Influenza usually feel very bad and prefer to stay in bed.

How long does a bout of Influenza last?

If you are healthy and suffer from an uncomplicated influenza attack, the high fever lasts about three to five days. After that you can continue to feel shaky and weak for days. You will usually start to feel fitter within two weeks. However, If you suffer from complications, such as pneumonia this may considerably affect the seriousness of the disease and its duration.

Are there different kinds of Influenza?

Influenza exists in three types: the A-, B- and C-type. But these viruses do not always stay the same. They change themselves continuously in such a way that our immune system doesn’t recognize it, so we can get sick again. This is the reason why the Influenza vaccine has to be adapted every year to these changes (also called mutations) in the virus.

The C type does not cause disease in the general population. The A-type can affect both animals and people. Until now, worldwide epidemics have always been caused by the A-virus. Influenza-B causes regional Influenza attacks, but can also spread to epidemic proportions. Type B only affects humans

Can I prevent Influenza?

Yes. Your doctor can give you an Influenza vaccination. The principle of each vaccine is that a tiny bit of inactive Influenza virus or only some components of the virus are injected into your body. The virus is inactivated to make sure it doesn’t infect your body cells. This allows your body to make antibodies so that you become immune against the Influenza viruses circulating this year.

What can I do about influenza, once I’ve got it?

Resting and letting the disease take its course is usually the best remedy. You can take medications to make the fever and pain more bearable. Drink as much as possible, to replenish the fluid you lose when you have a fever. After consulting with your physician, you may be given a new drug which may shorten the duration of your influenza symptoms by 1-2 days. This drug will only be effective if you start treatment within 48 hours after the onset of your clinical symptoms.

When should I go to the doctor?

Consult your physician whenever you are worried about your symptoms. You should in any case consult your physician in the following cases:

How often does Influenza occur?

Influenza outbreaks occur every year, sometimes there can even be outbreaks of two different kinds of Influenza. So every year you run the risk of catching Influenza. Sometimes these outbreaks are of local epidemic or even worldwide proportions.

When do we speak of an ‘epidemic’?

We speak of an epidemic when Influenza affects a lot of people in one country or area in the same period. Influenza spreads very quickly, especially with modern transportation methods such as airplanes. Epidemics die naturally, because once you’ve been infected with one particular type of Influenza, you’ve become immune to it and won’t catch it again. However, when a new form of Influenza comes along, your immune system won’t recognize it and you may become ill again.

We speak of a pandemic when influenza affects people in many different countries all over the world at the same time. Viruses that cause pandemics can spread so quickly because they are ‘unexpected’ viruses and people have no immunity against it. These viruses have not yet been included in the vaccine. They may be very strong, and make people sicker than usual. There is always the threat of a pandemic. There have been three major pandemics over the last century alone, in 1918, 1957 and 1968. The Spanish Flu in 1918/1919 was a particularly infamous pandemic with a death toll of 20 million around the world (more than the First World War). By the end of 1997 an avian influenza virus was found in humans in Hong Kong and some people died. Because of a potential pandemic threat with this new virus, all chickens in the Hong Kong region were slaughtered and no more cases were reported. It is important to remember though, that not only pandemics are life-threatening. During periods between pandemics in the last century, the total number of influenza-related deaths was even higher!

Risks of Influenza

Influenza can be dangerous in certain cases. It affects, and damages the respiratory tract tissues which can cause acute bronchitis, or even pneumonia. The body needs to be strong to battle the Influenza virus. For people with weaker health such as aging people, diabetics or people with heart disease, an attack of Influenza may ask too much strength and energy. They may easily catch a bacterial infection on top of their viral Influenza infection. In these situations, Influenza can be lethal.

In the United States alone, an estimated 20 to 50 million people catch Influenza every year. Influenza affects between 5 and 15% of the general population during epidemics. The percentage of persons with Influenza can reach 60% in certain closed communities such as nursing homes, with a mortality rate sometimes exceeding 30%. Thus the potential damage of influenza infections should not be underestimated.

Are you at risk of catching influenza?

Anyone anywhere can catch Influenza. For some people it is just a very bothersome bout of illness that forces them to stay in bed and miss days of work, study and normal life. For others it is a serious threat to their health or even their life.

Some people are at increased risk to suffer from complications, or even die from the effects of Influenza. They are:

Remember that if you or your children have regular contact with people belonging to these high-risk groups, you put them at increased risk of catching Influenza from you.

It has become clear that children have an increased chance of catching Influenza through schools and daycare centers, and so do their family members.

Benefits of vaccination

Influenza vaccination is the most effective measure for the prevention and control of Influenza. Especially high-risk persons have a lot to gain from vaccination, namely a substantial reduced risk of Influenza-related pneumonia, hospitalization or death.

Vaccination also leads to considerable cost reductions, in terms of national healthcare costs but also loss of earnings, and productivity.

When and how to get vaccination?

In the Northern hemisphere, the usual time to get vaccinated is in the fall: October-November (for countries in the world’s southern hemisphere, this means April-May). This will keep you prepared for the ‘flu-season’ that usually peaks in December and January. You can make an appointment with your doctor or health center to get your shot, or in some cases they will let you know when they have vaccination sessions and invite you to get a flu-shot when you belong to a high risk group. Many private companies have vaccination programs for their employees, so it is worthwhile to ask your company’s health officer about this.

Why should I get vaccinated?

If you belong to the risk groups, you should in any case get vaccinated. Why run the risk of serious complications if it can be prevented? And even if you don’t belong to the risk groups, why not try to prevent a very bothersome illness that keeps you from working and taking care of your children?

Additional to your own health and income, there are other things at stake. Sickness is expensive for society. The treatment of Influenza is costly, and there is a huge amount of lost working days and hence economical loss for companies and the society at large.

How long does it take after vaccination until I am protected from Influenza?

Influvac® is usually effective two weeks after vaccination, because then your body has made enough antibodies to protect you against the virus.

How long does the vaccination work?

At least six months on average. This is long enough to protect you for the duration of a complete flu season.

Why do I have to get vaccinated every year?

You need to get vaccinated every year because influenza viruses change over time. Therefore the vaccine is adapted every year to the viruses that are circulating that particular year.

Does Influenza vaccination give me 100% protection against catching Influenza?

If you are vaccinated against Influenza, you have a pretty good chance of not catching it when there is an epidemic. If you do get sick, it will be less serious than it would have been without vaccination. Viruses can change though, so you’re never completely without risk of catching influenza.

Does vaccination hurt?

Many people who should get vaccinated don’t do so because they are afraid of injections. It’s good to know that injections with Influvac® are practically painless. The specially designed syringe, the DupharJect®, with which Influvac® is administered, contributes to this lack of pain.

Does vaccination have side effects?

It is good to know that 95% of people vaccinated with Influvac® experience no or only very slight side effects. The most frequent side effect is pain and redness where you’ve been injected. Rarely people will experience some temperature increase and headache during the two days following vaccination.

Can vaccination cause Influenza in some cases?

No, this is a misconception. Vaccination with modern vaccines like Influvac® does not cause Influenza. All influenza viruses are made of killed virus preparations or parts thereof. Therefore these vaccines do not contain virus particles which can infect cells and make people ill.

Is there a difference in side effects between vaccines?

Influvac® belongs to the newest vaccines, called sub-unit vaccines. These cause the least side effects of all available vaccines. The first available vaccines contained whole viruses. This was effective, but caused many side effects. Over the years, companies such as Solvay Pharmaceuticals have been able to separate those parts of the virus that are not contributing to the immune response, from those that are needed for a good effect. This preparation method and the advanced purification techniques make Influvac® the best tolerated influenza vaccine.

What benefits do ready-filled syringes have for Influenza vaccination?

Ready-filled syringes are syringes that are already filled with the vaccine fluid. The DupharJect® with which Influvac® is administered is an example. The advantage of these syringes is that they reduce the risk of contamination of the syringe or the vaccine during administration. In case of the DupharJect®, this syringe has also been designed to make the vaccination as easy and painless as possible. It has exactly the right size for the intramuscular injection that is needed for a vaccine administration.

I’m pregnant, should I get vaccinated?

You can get vaccinated during pregnancy. Pregnant women are more prone to infections and an Influenza infection affects both mother and baby. Vaccination protects you from the risks involved. This is especially relevant for women whose third trimester of pregnancy is in fall or winter. It should be noted that some physicians will not vaccinate during the first semester of pregnancy because they try to avoid prescribing any medication or vaccine during this period.