Preguntas y respuestas 

Influenza disease

• What is influenza?
Influenza is a contagious disease caused by a virus - myxovirus influenzae. Often considered as a benign respiratory disease, the flu can trigger severe complications from pre-existing illness.
The infection:
- begins suddenly;
- may lead to symptoms that last more than 2 weeks;
- may keep one in bed for 3 to 4 days;
- can result in serious complications in high risk individuals.

• How to distinguish influenza from a common cold?
Even though influenza can show symptoms similar to those of a common cold, it is however far more dangerous. High fever (39°C-40°C), headache, severe cough, extreme fatigue, aches and pain, are typical flu symptoms. Unlike a common cold, influenza can cause severe illness and life-threatening complications in many people.

• How can one catch influenza?
Influenza is a highly contagious disease. It is transmitted through air droplets from someone who is sneezing or coughing; from close contact with someone who has influenza or from touching contaminated objects.

• Is there any treatment for influenza?
For most people, influenza involves an upper respiratory tract infection, which the body will eliminate after several days, and requires symptomatic treatment only.

Antibiotics are not effective against the influenza virus but may be used to treat influenza complications such as secondary bacterial infections.

Antiviral drugs are effective in preventing the flu by reducing the duration and intensity of symptoms. These medications are prescription drugs, and a doctor should be consulted before they are used. (1)


• Is it possible to prevent influenza?
Yes, it is possible to prevent influenza through vaccination. The efficacy of influenza
vaccines has been clinically proven. Many countries all over the world recommend vaccination during the flu season.

• What should one do if catching influenza?
When having influenza, the best thing to do is to rest in bed and keep warm, drink plenty of fluids and regularly take paracetamol to lower temperature and relieve aches.
Consult a doctor, if necessary.

Influenza vaccination

• Why should one get a flu shot every year?
The influenza virus is characterized by its mutating capacity. Generally, new influenza virus strains circulate during flu season. Each year, prior to the influenza season, the most active viruses are identified by the World Health Organization and included in a new vaccine formula in order to offer the best protection.

• Can children be vaccinated against influenza?
Yes. The vaccine can be given to children aged 6 months and older.

Influenza vaccine administration

• When is the best time to get vaccinated against influenza?
Vaccination should take place every year before the influenza season as soon as the new vaccine becomes available.
It is never too late to get vaccinated even during the influenza season. However, once vaccinated, the body needs two weeks to produce protective antibodies.

Indication

• Who is at risk?
Anyone can get the flu including healthy people. Influenza can be transmitted unknowingly to others, as it takes 1-4 days for symptoms to appear.

Some people are at an increased risk of developing life threatening complications if they catch influenza, e.g. the elderly, adults and children who have diabetes, asthma, and chronic heart, lung and kidney disease.

• Are children at risk of catching influenza?
Children with chronic conditions are especially vulnerable to influenza. They are at an increased risk of developing life-threatening complications. This risk is especially significant for children with asthma, diabetes and chronic heart, lung or kidney diseases.  Children who get the flu at school can be a source of contamination and transmit it to other family members.

Influenza vaccine in patients with specific conditions

• Should we recommend influenza vaccination for asthmatic patients?
Yes. According to recommendations from most of health authorities, annual influenza vaccination is indicated for anyone aged 6 months and older who is at elevated risk for complications, such as asthma (2).

• Is it possible to vaccinate diabetic patients?
As patients with diabetes are at increased risk for morbidity and mortality during the influenza season, Health Authorities recommend vaccination.(2)

Moreover, studies have demonstrated that diabetic patients have similar response to vaccination as healthy subjects (3) and that vaccination is effective in reducing hospital admissions.

• Should we vaccinate pregnant women?
Because of the increased risk for influenza-related complications, vaccination can be appropriate for women who will be pregnant during the influenza-season. The vaccination must be prescribed by a doctor.

Formulation and production

• How does the WHO choose the strains to be included in the vaccine?
The recommendations regarding the strains to be included in the vaccine formulation for the next year are the result of a careful, prospective and thorough monitoring of the virus by the WHO and its global network of laboratories.

• Why does the vaccine protect against 3 different strains?
Three different viral strains are currently circulating worldwide. Influenza viruses affecting humans are mainly A or B strains, with several subtypes in each group. The predominance and virulence of each type vary from one year to another.
Two types of A strains are currently circulating. The B type can also cause severe epidemics.

Efficacy

• How has vaccination proven to be efficacious?
Numerous clinical studies have demonstrated the efficacy of the influenza vaccine. Based on those studies, the WHO recommends vaccination as the most effective way to prevent influenza and reduce the impact of epidemics. Various types of influenza vaccines have been available and used for decades. They are safe and effective in preventing both mild and severe outcomes of influenza.

• What are the benefits of influenza vaccination?
Vaccination can :
- save the live of people at risk;
- avoid or shorten illness and hospitalization;
- avoid or shorten sick leaves;
- reduce the risk of transmitting influenza to family members, friends or co-workers.


• How much time does it take to develop immunity after administration of influenza vaccine?
According to the Centers for Disease Control and Prevention (USA), about two weeks are required after vaccination for antibodies to develop and warrant efficient protection against influenza virus infection. That’s why it is better to get vaccinated in the early fall, before the beginning of the flu season.

Influenza vaccine and adverse reactions

• Is influenza vaccine safe, can we get influenza because of the vaccine?
The vaccine does not cause influenza. It contains a non-infectious and killed virus which role is merely to warn the body about the virus threat.

Influenza vaccines are well tolerated and safe. The most frequently associated reaction is mild soreness at the injection site that can last 24 to 48 hours.

It is important to note that other viruses circulating during the winter season can trigger respiratory illnesses with the same symptoms as the flu.

SARS (Severe Acute Respiratory Syndrome)

• Is there a link between SARS and influenza?
No, because influenza and SARS come from different families of viruses.

According to the World Health Organization (WHO), influenza vaccination does not protect against SARS, but can reduce the occurrence of respiratory diseases that could be mistaken with SARS.

Avian Flu

• Is the influenza vaccine effective against avian flu?
Avian influenza, or “bird flu”, is a contagious disease affecting animals. Caused by influenza A viruses, it concerns mostly birds and, less often, pigs and other animals.

Avian influenza viruses may be transmitted to humans – even if it is extremely rare – but no case of person-to-person transmission has been strictly confirmed.

According to the World Health Organization (WHO), available influenza vaccines do not protect against avian flu but can prevent the appearance of a new virus which could occur if an unvaccinated human was to be infected by both human and avian influenza viruses.

(1) CDC. Antiviral drugs and the Flu : http://www.cdc.gov/flu/protect/antiviral/index.htm
(2) The Canadian Lung Association. Asthma Facts and Statistics. http://www.lung.ca/asthma/facts.html
(3) American Diabetes Association. Immunization and the prevention of influenza and pneumococcal disease in people with diabetes. Diabetes Care 2003,16 suppl1

Internal ref: CIRC. 06/10/COM/060