Influenza is a viral disease that affects the respiratory system. The initial symptoms are often similar to the common cold but gradually become more severe. Symptoms may include high fever, chills and body aches more than usual. If left untreated for a long time, it can lead to complications and other diseases such as myalgia, pneumonia, pneumonia and even death.

Influenza vaccination is therefore essential and can reduce the severity by about 70-80 percent.

Influenza is classified into the following four categories:

• Influenza A / H1N1 virus, also known as "New influenza 2009" is a contagious disease that spread from Mexico to many countries very quickly, the disease is caused by a mixture of both human and animal strains until it mutates and spreads from person to person. Symptoms that indicate this disease are high fever, runny nose, cough, and respiratory disorders. Some people may have diarrhea as well. This disease can be treated by an anti-drug called "Oseltamivir".

• Influenza A / H3N2 virus is a virus that can be transmitted from pigs to humans. There was a severe epidemic in Hong Kong and made it also known as Hong Kong Flu. Patients with this disease may have symptoms like a common cold but generally have other symptoms along, such as muscle aches, rapid breathing, shortness of breath, etc.

• Victoria B Colorado influenza virus is an epidemic in cold, dry climates or during winter. It spread only from person to person. Patients with underlying disease are at a higher risk of developing it.

• Influenza B Phuket virus (Yamagata lineage) generally spread from December to January. The most vulnerable group is children younger than 2 years old, pregnant women and the elderly.

The Influenza vaccination should be done annually because the body's immune responding to the disease gradually declines after having been vaccinated for a while. Each year the strain of influenza virus continues to change. Therefore, vaccination is required every year to keep the body immune to prevent directly to the strains that are spreading

Influenza vaccine is a vaccine that people can inject. However, they should be people older than 6 months old. Children under 9 years of age who received influenza vaccination for the first year should receive 2 doses, by receiving the second dose 4 weeks away from the first. People at risk are recommended to receive it one dose of vaccine per year at regular intervals to help prevent the severity and spread of influenza.

Who should get the flu vaccine?

Everyone should receive the influenza vaccine as the basic vaccine. It can be injected from newborns after 6 months of age up to adulthood. In addition, people at risk are advised to get the vaccine as well, including the elderly, 65 years or older, pregnant women and people who are at risk of having diseases, such as kidney disease, heart disease, liver disease, and people with immune problems.

Who is forbidden to get the flu vaccine?

• Children under 6 months old
• People with a history of allergic reaction to the influenza vaccine or any ingredient in the vaccine
• People with high fever or a severe infectious disease (People with low fever can inject it, should consult a doctor)
• People with a history of severe egg allergy because most influenza vaccines contain egg protein. For those with a history of mild fever allergies, the vaccine can be vaccinated but must be monitored for at least 30 minutes after the injection. However, consult your doctor for further immunization recommendations to prevent the flu.
• People who are sick or have previously been ill with Guillain-Barré Syndrome: GBS
• People who have recently recovered from an acute illness for not more than 7 days
• People who have recently been in bed and have been discharged from the hospital for less than 14 days
• People who still cannot control symptoms of congenital disease.

In addition, for people with a high fever or an acute illness, this vaccine should be avoided until fully recovery to prevent any side effects that may occur.

Why get vaccinated against influenza virus every year?

The strain of influenza virus changes every year and there is also a great variety. Therefore, getting vaccinated against influenza virus is to protect against strains that can change from year to year, especially during the period before the rainy season which is the time when the most outbreaks occur. Therefore, the vaccination should be approximately 2 months in advance for the vaccine to create a highly effective immune system, which was during the outbreak.