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Flu shots are harmless for the majority of people. The vaccines are never completely protective but are estimated to help about 70 percent in creating antibodies to the current year’s batch of flu viruses.
The making of the vaccine is complicated and is made complicated by the viruses’ biological changes, which is called antigenic shift. An influenza virus has the basic viral composition of only a protein coat encapsulating genetic material that guides its replication and existence as a parasite of whole host cells. It is not a whole cell, and must use a host cell’s machinery to reproduce (sounds kind of kinky?).
The flu viral groups or genera, as we humans define them, are A, B and C. Not complicated yet, eh? The C viruses play little role in human disease. After being sorted into their alphabetical classes by their differing nucleoprotein and matrix proteins, strains are designated according to geographical site (like St. Louis, Hong Kong) where first identified, the specific isolate number, via the Center for Disease Control and World Health Organization, etc., and subtype. Those are the hemagglutinin (H) and neuraminidase (N) letters you see in a virus’ name. For example, the A/Wisconsin/67/2005 (H3N2)-like antigen was in last year’s mix of viruses (avoid Wisconsin in flu season?).
The H protein allows the virus to bind to a host cell and enter it. The N protein breaks down the H receptor, letting the new viruses make a break out of the cell and spread. Each year’s vaccine is based on prior years’ existing viruses, which are grown in the lab, harvested (those sub-microscopic combines are so cute), and either killed/inactivated (the viruses in the shot) or weakened/attenuated (those in the FluMist nasal vaccine). It’s sort of a crap/viral shoot to create a vaccine combination to protect for the coming year because the subtle changes the viruses can make in their protein parts (antigenic shift) can make your antibodies to the vaccine viruses not recognize the slightly different new (and improved from the virus’ view) viruses to inactivate them. Hence, the hit-and-miss nature of each year’s vaccine formulation.
Who should get the shot? According to this year’s CDC vaccine information statement for the killed recipe, all children 6 months to 18 years (tell an 18-year-old he/she is a child?); anyone older than 50; anyone with long-term medical problems such as heart, lung, kidney, metabolic, liver diseases, or asthma or anemia; anyone with a weakened immune system, such as cancer patients; residents of nursing homes and other chronic care facilities; anyone who cares for people medically, such as health care providers of any status; and anyone living in a communal place, such as a dormitory or prison (Care to make a comparison?). Who did we leave out?
Who shouldn’t get the shot? Anyone with an egg allergy, because the viruses are grown in eggs; anyone with a known reaction to a prior flu vaccine; anyone who is sick or recovering from the flu.
Reactions to the shot can include local skin irritation and occasionally fever and aches for one to two days. Severe problems are extremely rare.
Why get the shot? The CDC data say that, on average, 226,000 people are hospitalized each year from influenza, and 36,000 die from its complications, mostly, but not exclusively, the elderly. Complications include secondary lung, blood or systemic infections that may invade when your defenses are compromised. Also, the stresses that occur on other diseased organs can make them malfunction and quit. Who should get the live attenuated vaccine is another discussion, best taken up with your doctor. The killed vaccine never causes any influenza infection. The live one rarely might.
The shot is not as bad as having a baby or a cow stepping on your foot, and the risks are inconsequential. It isn’t perfect, but what is (except you and me?)? To clarify, influenza is a lung/respiratory infection only. It has nothing to do with “stomach flu.” Different viruses, different organ system. The shot won’t help that when “that flu” flies outa ya.
