Monday, February 8, 2016

Why is the 2015-2016 such a mild influenza season?

     This has been a busy winter with so many cold, coughs, vomiting and diarrhea illnesses! But remarkably, it has been a very mild influenza season. We have only seen a handful of cases since the start of the season. Many parents are asking me "Why, Dr. Tim?".
     Weather plays a part in many illnesses. The classic pediatric example is croup. The number of cases of croup we see is correlated with weather changes. The more the weather flip-flops around, the more cases we see. That has been true this cold and flu season. However, it is hard to say that this milder winter is changing our influenza season. The last really mild winter a few years ago was accompanied by a really bad influenza season! So, we cannot give credit to the weather this past few months.
     How many people are vaccinated with the influenza vaccine plays a part in the influenza season. I would love to say that this influenza season has been mild because we vaccinated so many kids with the vaccine in the Fall, but that is just not the fact. Due to the nationwide shortage of the FluMist (nasal spray influenza vaccine), we vaccinated about 1000 kids less than we usually do each year. Judging by that fact, we should be having a bad influenza season. But that is not the case.
     How well the influenza strains of the vaccine match the virus in the community plays a part in the severity of the influenza season. There are four (4) different strains in the injectable flu vaccine and the FluMist. Some years, the educated guessing game that the scientists play in picking the four strains is more successful that other years. This year, there is a very good match between what strains are out and about in the US and what was in the vaccine. So that is helpful, but probably not enough to help prevent the influenza as successfully as has happened.
     Why then are we having a mild season? I think the vaccine strains matching the strains in the community is helping. Plus we are just lucky enough to be having a good, mild year! Keep getting vaccinated!