Influenza viruses have been around since the dawn of mankind. They have often caused widespread epidemics with severe symptoms that took the lives of hundreds of thousands of people. Science has allowed the medical community to develop an effective vaccine to immunize the population against certain commonly encountered influenza viruses. Understanding how these vaccines work will help to promote their use in the community.
Types of Influenza Viruses
The most common viruses that people acquire during flu season are influenza A and influenza B. Within these two categories are other subcategories or adaptations of these viruses, but they still fall into these two basic categories. An influenza type C also exists but this infection only causes mild respiratory symptoms and is not associated with widespread dangerous outbreaks of the flu.
Viral Changes, Shifts and Drifts
One of the features of viruses in the world of microbiology is that they undergo changes in structure to adapt to changing conditions. Antigenic drift produces new strains of disease that may not be recognized by the body, and the person then becomes infected by the new strain. Antigenic shift is said to occur when a major change is suddenly seen in certain proteins of the virus. When this large change occurs, the population will have no immunity to the completely new strain and a pandemic will result. This type of change usually only affects influenza type A viruses.
Annual Influenza Vaccines
The challenge of vaccine manufacturers is to counteract the small changes in influenza viruses that naturally occur over time. In this way, one or more factors of the vaccine will be slightly different each year in order to provide increased immunity against the changes. Flu shots generally contain vaccines against both influenza A and influenza B viruses. Vaccines are chemically manipulated to accommodate the small changes in viral composition and helps to prevent large numbers of people from acquiring the flu and the sometimes-dangerous secondary infections that result from the flu.
Whose Is Most At Risk For Getting The Flu
School children are often the first to become ill with the flu because they may not have sufficient immunity built up from previous years. Newborns, pregnant women and the elderly may also be at particularly risk for complications from the flu. Any person with a severe illness or debilitating condition should be particularly careful about getting their yearly flu shot. On average, 5 to 20 percent of the population will get the flu each year. As many as 200,000 people are hospitalized each year because of flu symptoms. Over 20,000 people die each year from flu-related illnesses.
Who Should Not Get A Flu Shot
Physicians recommend that most people get an annual flu shot to support proper influenza immunity in the community. However, in some cases, patients should carefully discuss the matter with their physicians to determine if getting the shot is advisable. Those with severe, life-threatening allergies, those with Guillan-Barre Syndrome, people who are feeling unwell or people with immune system disorders may be advised to skip the vaccine. Your physician may advise either the live or inactivated vaccine, depending on certain medical factors.