Why vaccinate for flu?
Flu (or common flu) is medically referred to as influenza. It is a viral infection that develops primarily in the lungs thereby affecting the whole respiratory system. It is usually spread from person to person through secretions of the nose and lungs.
Generally, the stretch across November and April is known as the flu season. However, most of the cases occur between late December and early March. Therefore, it is advisable to take the flu vaccine between September and mid-November. Though, it can also be taken at other times of the year, administration of the vaccine before the flu season gives the body a chance to build up the required immunity that protects it from the flu virus.
Flu is a very common illness. Every year in the US, about 5 to 20% of the population gets flu, 200,000 plus people are hospitalized due to flu complications, and about 36,000 people die from these flu complications. Effective flu vaccination at the right time can reduce these numbers and give people a better chance at fighting it off.
What is flu vaccine?
The flu vaccines are of two types:
- The flu shot
- The nasal sprayflu vaccine.
The "flu shot"
This is an inactivated vaccine that contains only dead virus. This is given with the aid of a needle usually in the arm. This vaccine can be given to people above the age of 6 months, which includes all healthy people as well as people with chronic medical conditions. The inactivated flu vaccine is a single dose of 0.5 ml of liquid. This liquid is injected into the body through the skin into muscle (intramuscular or IM). Usually, the vaccine is injected into the deltoid muscle at the side of the arm.
The nasal spray flu vaccine also known as LAIV for "live attenuated influenza vaccine" or FluMist® was first licensed in 2003. Though it is directed against the same strains of virus as the flu shot, it contains live, weakened flu viruses instead of killed viruses that do not cause severe flu symptoms. As the viruses are weakened it is called Live Attenuated Influenza Vaccine (LAIV).
This vaccine is approved by the US Food and Drug Administration (FDA) for use in healthy people between 2 and 49 years of age. However, it is advised that the following group of people who are at risk for serious complications should not be vaccinated by the spray flu vaccine:
- People with chronic health problems related to heart and lungs.
- People suffering from suppressed immune function.
- Care givers or people who come in contact with those with a suppressed immune system.
- Children who suffers from recurrent wheezing and are less than 5 years of age.
- Children or adolescents who are on aspirin therapy.
Composition of flu vaccine
The seasonal flu vaccine contains three influenza viruses, one A (H3N2) virus, one regular seasonal A (H1N1) virus (not the 2009 H1N1 virus), and one B virus. However, the viruses in the vaccine are changed every year on the basis of international surveillance and scientists' estimations regarding the types and strains of viruses. It takes about two weeks from the vaccination for the antibodies that protects the body against influenza virus infection to fully develop.
Flu vaccines should be given to the following groups of people to protect them from flu and complications arising from flu:
- Children with chronic heart or lung disorders like asthma.
- Children with chronic diseases like diabetes mellitus, kidney disease, severe anemia, or immune deficiency. The immune deficiency can be caused either by HIV/AIDS or it can be immune suppression caused by drugs.
- Children who are born prematurely are at an increased risk of developing lung problems in case if they get infected by influenza.
- Children who are undergoing long-term aspirin therapy are at a risk for Reye syndrome in case if they get infected by flu. Reye syndrome is a serious illness that affects the brain and liver. It usually occurs in children recovering from a viral infection.
- Care givers or people who come in contact with such children.
- Adults with chronic heart or lung disorders like asthma.
- Adults with chronic diseases like diabetes mellitus, kidney disease, severe anemia, or immune deficiency. The immune deficiency can be caused either by HIV/AIDS or it can be immune suppression caused by drugs.
- Pregnant women are also considered to be in the high risk zone. This is because, during pregnancy, if a woman gets infected it will put both for the mother and the baby at higher risk of flu complications. Moreover, if the mother gets sick with flu she might pass the infection to her new born baby.
- People involved in social activities like police, firefighters, and other public safety workers.
- People working at nursing homes and other facilities that supports people with chronic medical conditions.
People who should not receive the flu vaccine?
However, there are some people who should first consult a physician before getting a flu vaccine.
This group includes:
- People who have severe allergic sensitivity to chicken eggs. This is because the ingredients for flu shots are grown inside eggs.
- People who have a history of hypersensitivity to influenza vaccination.
- Infants less than 6 months of age, as this vaccine is not approved for them.
- People who are suffering from moderate to severe forms of fever. However, if a person is suffering from cold or mild illness without fever, he could be vaccinated.
- People suffering from Guillain-Barré syndrome (GBS), a rare condition that affects the immune system and nerves. In 1976, GBS developed in people who were vaccinated by swine flu vaccine. However, a single study has shown that one person out of one million vaccinated people may be at risk of GBS associated with the vaccine.
How effective is the flu vaccine?
The effectiveness of the flu vaccine depends on the age and health status of the person getting the vaccine. If the viruses in the vaccine match with those in circulation in the body the vaccination becomes very effective.
Flu vaccine side effects
As the flu vaccines are of two types, the side effects are also of two types depending on the type of vaccination.
Flu shot side effects
- Soreness, redness, or swelling of the region where the shot was given.
- General side effects like fever, malaise, and myalgia may also occur. However, these occur mainly in people who never had a flu shot before.
- Allergic reactions may also occur.
In case if these problems occur, they begin soon after the shot and usually last for a couple of days. Flu shots rarely cause any severe complications.
Nasal flu vaccine side effects
The live viruses in the nasal-spray vaccine are weakened. Therefore they do not cause any severe symptom. However, mild symptoms may occur after vaccination like:
- Runny nose
Some children may also develop mild fever and muscle aches. Additionally, some children also suffer from symptoms like wheezing, headache and vomiting.
Written by: Healthplus24 team
Date last updated: September 22, 2012