The flu is a common respiratory system illness caused by the influenza virus. The severity of the illness ranges from mild to severe. On average every year, about 36,000 people in the United States die from causes related to influenza infection, according to the Centers for Disease Control and Prevention (CDC). The single best way to protect yourself from influenza infection is to get a flu vaccination yearly; they're usually available every fall. The types of vaccines available include an inactivated virus, a live "attenuated" virus and, in 2009, a vaccine to protect against a form of influenza known as H1N1.
Like all medical interventions, vaccination carries its own risks. Those with known hypersensitivity to components of the flu vaccine (such as eggs) should not receive the vaccine, unless they are at high risk, in which case they should be desensitized to the allergen before vaccination. The live virus carries higher risks, and people who are pregnant, under 5 or over 50 years of age, with cardiopulmonary or renal disease, immunodeficiency syndromes, or children on aspirin therapy should receive the inactivated form instead.
Inactivated Vaccine
The trivalent inactivated vaccine (TIV) gets its name from the use of formalin, which kills, or "inactivates" the virus. This is typically recommended for children between the ages of 6 months to 5 years and older children or adolescents at high risk, according to "Principles and Practice of Pediatric Infectious Diseases." High risk refers to those with preexisting diseases that can make them more susceptible to severe infection, as well as individuals who come into contact with them.
Live Vaccine
This vaccine contains a live virus that has been modified, or weakened, and is known as the Live Attenuated Influenza Vaccine (LAIV). This is recommended for healthy individuals between the ages of 2 and 49 who are not pregnant at the time of administration, according to "Principles and Practice of Pediatric Infectious Diseases."
H1N1 Vaccine
In 2009, a newer form of influenza, known as H1N1, became prevalent and normal vaccination did not protect against infection from this strain. As a result, researchers developed both inactivated and activated forms of vaccination for this strain that are available to the general public. Certain groups are at priority for immunization with this form and include health care workers, pregnant women, those with preexisting diseases and people aged 6 to 24, according to CDC.
References
- CDC: Key Facts about Influenza
- Principles and Practice of Pediatric Infectious Diseases, 3rd ed; Sarah S. Long; 2008
