Influenza (Flu) and Influenza Vaccine

Influenza is a type of respiratory illness which affects millions of people each year. There are many different strains of influenza viruses, but the most common would be the seasonal flu. Although common, influenza is a still a very serious medical condition which can be avoided through vaccinations.

What is influenza?

Although many people are familiar with the flu virus, many people still wonder, what is the flu? Influenza is considered a respiratory illness affecting both the upper and lower respiratory system. Flu symptoms include fever, chills, headache, coughing, runny nose, severe fatigue, weakness, body pain and general discomfort. Occasionally, in small children influenza will be accompanied by nausea and vomiting. This can sometimes be caused by nasal drainage into the stomach. The term “stomach flu” is misleading as true influenza virus does not affect the digestive system. Influenza proves to be an extremely serious illness in the elderly and the very young. This is because influenza can turn into more serious conditions such as pneumonia.

Where does influenza come from?

Influenza viruses infect birds and mammals, and can switch hosts to form new lineages in novel hosts. Influenza pandemics have been affecting the human population for at least 500 years, but there have only been four since 1918. The influenza pandemic of 1918, also referred to as Spanish Flu, caused almost 40% of the world’s population to become ill, while nearly fifty million died as a result of the illness. Each following pandemic was caused by some aspect of the virus evolving in such a way that previous vaccines and natural antibodies could not fight it. The most recent influenza pandemic was caused by the H1N1 virus which spread quickly around the world. This strain of influenza was dubbed swine flu because of it origination within pigs. The Center for Disease Control and Prevention was able to quickly develop a vaccination for H1N1 and the pandemic was put under control swiftly.

How is influenza transmitted?

Influenza is generally transmitted by means of sneezing and coughing. When an individual sneezes or coughs, aerosols are created in the air that carry the viruses to another host. Other ways of coming in contact with the virus would include coming into contact with bird droppings or nasal secretions. These types of direct contact contamination can be greatly decreased through thorough hand washing and avoiding practices that spread germs like touching your eyes/hands/mouth, shaking hands or sharing eating/drinking utensils. In severe cases, medical nose masks can be worn to further prevent the transmission of airborne viruses as well.

What are influenza symptoms?

Symptoms start 1 – 4 days after the virus enters the body. The beginning of the influenza virus is usually marked by congestion and runny nose. Severe body pain will often be the first sign to an individual that they have contacted more than just a common cold. Body pain can in some cases be so severe that the individual will be confined to bed for several days. Another early symptom is the sensation of being cold or shivering while running a fever. This presents a real health risk to younger children as they will attempt to warm themselves up by bundling which can make their fever spike causes more complications. Young children will often complain about abdominal cramps or even nausea and vomiting. Many people want to know, how long does the flu last? Most symptoms tend to last from seven to ten days and in most cases the individual is rendered confined to bed. Most healthy adults may be able to infect other people beginning 1 day before symptoms develop and up to 5 – 7 days after becoming sick.

What is the influenza vaccine?

The CDC has worked tirelessly for many years on creating and perfecting flu vaccines in an attempt to keep up with the demand, as well as with the ever-evolving strains of the flu. There is a trivalent (protecting against 2 Influenza A and 1 Influenza B viruses) and a quadrivalent (protecting against 2 Influenza A and 2 Influenza B viruses) flu vaccine. The vaccine either live, attenuated or inactivated, and comes in form of an intramuscular injection or an intranasal spray. The common flu vaccine is especially recommended for high-risk groups such as the very young, the elderly and pregnant women. People who come in regular contact with these high-risk groups should also get the flu vaccine to protect the more vulnerable populations. The flu shot ingredients include a certain strain of the virus with preservative ingredients. Injecting a healthy individual with the vaccine will give their body a chance to build up immunity to the virus under ideal circumstances. However, because of the high mutation rate of the influenza virus, one vaccine will only offer immunity for a few years. The flu vaccine effectiveness is high and is recommended by the World Health Organization.

What are the influenza vaccine side effects?

Flu vaccine side effects include an immune system reaction similar to what an individual would experience if they had actually been infected with the virus. Many individuals will experience very mild cold or flu symptoms. However, they will not experience influenza. These symptoms will be mild and not as long lasting as the symptoms associated with actual influenza.

Who should not get the influenza vaccine?

People with severe (life-threatening) allergies (including an allergy to eggs), with a history of Guillain-Barré Syndrome or sick people should not get the inactivated flu vaccine. Pregnant women, people with a weakened immune system or long-term health problems, young children with asthma or wheezing problems or people in close contact to individuals with very weak immune systems should not receive the live flu vaccine.

Sources:

http://www.cdc.gov/flu/

http://www.cdc.gov/vaccines/vpd-vac/should-not-vacc.htm

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2862331/

 

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