As the H1N1 (also known as Swine Flu) pandemic has progressed, one thing that has become clear is that the older adult population has gotten a break for a change.  Although some fatalities have occurred from the disease, most cases have been relatively mild and found mostly in children and young adults.  Surveillance reports indicate that only  14% of hospitalizations for  H1N1 flu have been found in those 50 years old and over and a much smaller proportion ( 9%) in the 64 and over age category.  Worldwide, roughly 4,000 people have died and it has been identified in 191 countries.  It is not entirely clear why this has worked out the way it has.  There was some thought early in the epidemic that a similar virus had circulated in the older population conferring some immunity to the current strain of H1N1. A form of swine flu was present in the 1970’s but the feared epidemic never materialized so there was not widespread infection or exposure.  It has the greatest similarity to the virus that caused the 1918 Spanish Flu pandemic but, of course, that’s been over 100 years ago.  Epidemiologists tested elders for antibodies to H1N1 (which indicates previous exposure) but they were not present in most individuals.  We know that the immune system declines in its ability to respond to an infection as we age.  Ironically, this characteristic may be beneficial in this instance. 

When a foreign invader such as a bacteria or virus is recognized, the immune system starts producing infection fighting proteins called cytokines and white blood cells that circulate in the bloodstream.  Some in the health care community believe that young people are being affected more severely because their immune systems are vigorous and initiate an overwhelming response to the virus that taxes the body’s organ systems to the point that recovery is slow or impossible.  Most young people who have died have had pneumonia and many have had underlying medical conditions such as asthma, diabetes, heart or neurologic diseases.  Because of swine flu infection trends in the population, older adults are considered to be at lower risk than babies, youth and pregnant women for this particular virus.  Health care workers are also considered higher risk because of contact with individuals who are ill.  Seasonal flu, ondi the other hand, kills 36,000 people a year in the U.S. either directly or due to complications and the majority of those individuals are over 80 years old. 

A vaccine was developed that is specific to this particular strain of H1N1 and although it was initially feared that the virus might change its “personality”, but it hasn’t done so.  The vaccine was manufactured in exactly the same fashion as the seasonal flu vaccine and with the same safety standards.   Two forms are available, both of which are made with a killed or weakened virus, so no live virus is present and cannot cause people to catch the flu.  All the vaccine was bought by the Federal Government and the incidence of the disease is being monitored by the Centers for Disease Control in Atlanta.  The vaccine is being distributed by geographic areas that have the highest rates of infection and to the populations most affected.  There is a vaccine administered by nasal spray but it is not recommended for anyone over 49 years old or those with respiratory problems such as asthma.  There is also the usual type of vaccine administered by injection but it has not yet been distributed.   Some fear is present in the population surrounding the vaccine itself.  Many feel it was developed in too hasty a fashion and not sufficiently field tested.  Others remember the catastrophic reactions that a few individuals suffered with the previous swine flu vaccine which resulted in cases of paralysis.  Another group is concerned about the ingredient called Thimerosol because it contains small amounts of mercury.  This ingredient is used to inhibit bacterial growth in multi-dose vials of vaccine that could become contaminated by repeated needle sticks into the vial to draw up the medication.  This is a special concern among some parents of infants and young children who receive numerous vaccines in a relatively short period of time.  No Thimerosol has been used in vaccine manufacture for pediatric immunizations in the U.S. since 2001 and only trace amounts are found in multi-dose vials at present.  Mercury exposure is NOT a significant concern for swine or seasonal flu vaccines.  While the elderly population is at lower risk for swine flu that some other elements of the population, getting immunized still merits consideration.  And I heartily recommend elders get a yearly immunizations for the seasonal flu normally present in the winter and early spring months.  It takes roughly 2 weeks to develop immunity after getting a vaccine and in the case of seasonal flu, the immunity will last for 2 to 3 months. 

Sources used for this article included news stories from med page.com, Bloomberg, Huliq, Dallas Morning News, the LA Times and information from the Centers for Disease Control and the Federal Drug Administration.