New flu vaccine recommendations for 2011 were released by the CDC this week. Flu season is generally from November to March in the northern hemisphere. Many people are not aware that influenza is a deadly virus. We must not confuse “the flu,” a term used loosely for run-of-the-mill upper respiratory viruses, with “influenza” which causes high fevers, body aches, sore throat and is sometimes complicated by secondary bacterial pneumonia and death. The influenza virus attacks the lining of the upper respiratory tract, rendering it less effective at clearing secretions and fighting other bacteria. I tell people that influenza’s effect on the lungs is like having a skinned knee – and that your lungs, like a skinned knee, are at risk for further infection until everything heals. The influenza virus has caused more documentable deaths world-wide than any other virus in history. This is because the influenza virus readily mutates, creating new strains. These mutations are usually small and the new virus is not so different that the average person’s immune system cannot handle it…If the immune system recognizes something similar to what it has been exposed to before, it is better prepared to defend against it. Unfortunately, the influenza virus occasionally mutates to such a degree that the population on whole has not seen anything like the new strain. When this happens many people die from influenza. These new mutant strains cause “pandemics.” In 1918, the Spanish flu caused the death of between 25 to 100 million people globally. These pandemics have historically come about every twenty to thirty years – We are now in the zone for a pandemic.
Pandemics are different than typical influenza outbreaks in who they affect the most. If you look at mortality from the typical influenza virus, you see a “U” shaped curve, with deaths occurring in the very young and the very old. Pandemic influenza has a “W” shaped curve, meaning that there will be some deaths in the very young and old, but it is the people in the middle (the healthy adults in the prime of their lives) that die from influenza. This is because the people in this age group have not lived long enough to have sufficient exposure to influenza to create an immunologic memory of the rare strains.
With the release of the latest CDC recommendations, I want to make the point to immunize. I am well aware of the concerns that some people have over vaccinations. I have a son who is autistic and have considered the claims against vaccination. I am also aware of the massive public health implications of a pandemic influenza virus. There are small risks for side effects with every vaccine. The risks for not immunizing against influenza, I feel, are much greater. This year’s vaccination recommendations are very similar to last year. In fact, the vaccine strains this year are the same as last year. The vaccine is produced using chicken eggs so if you have an egg allergy, you should consult with an allergist. It is important for pregnant mothers who will be in there second and third trimester during flu season and children over the age of 6 month to consider vaccination. This group is at increased risk for severe influenza and is typically under-vaccinated. There is a new “intradermal” vaccine available this year; I would call an “influenza-light.” The injection is not as deep (muscular) as the standard influenza vaccine and is half the normal dose. This is recommended for those in the 18 – 64 age range. Please talk to your physician about vaccination for influenza. As always, decisions regarding your care should be personalized to you with the consultation of your physician.