COMMENT: Sir,

REPLY: The influenza virus changes its genetic makeup every year and complies with guess what – cyclical analysis! This constantly changing virus presents a cyclical challenge to medical science, and consequently, this makes it impossible to create a single vaccine to prevent the disease for life. The World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) monitor each new strain of influenza virus as it appears. The gather data and then try to predict which may be the predominant virus in the following year’s flu season.  Scientists then use this data to develop a vaccine each year against the specific virus they predict will predominate. Sometimes they are correct, and sometimes they are off the mark.

The virus known as influenza is a master at evolving to elude the human immune response by mutating so quickly that it soon becomes unrecognizable. We are actually at war with this virus which is mutating to survive and beat us at our own game. There are actually several active flu strains in the world that run around. Each year, we try to evaluate which strains of flu virus are predominant in the United States and change the vaccine recipe as necessary according to this cycle in nature. The accuracy of the recipe determines how effective that year’s vaccine will be.

Make no mistake about it, this is nature’s way of thinning the herd. We can give it our best shot at trying to combat disease, but it responds to our actions and mutates. This is simply a war with nature determined to win.