Saturday, May 3, 2014

Truths of Vaccinations, part II

Part two in my series on vaccinations

Myth: I’m not a danger to people if I don’t vaccinate myself
You are a danger to others if you chose not to vaccinate yourself (or your children).  See that infant? She’s too young to receive the whooping cough vaccine, but she has a 1 in 200 chance of dying from it, as well as a 50/50 chance of needing hospitalization.  Infection could last up to 100 days, and will require supportive treatment, such as oxygen, IV nutrition and fluids, and possibly mechanical ventilation.  See that bald man?  He has cancer, and his body can’t fight infections due to the chemotherapy.  The flu could easily kill him.  See that little boy wearing a mask? He is immune-compromised from a genetic condition.  He can’t be vaccinated because his body doesn’t form antibodies in response to vaccines, so they are not effective for him.  See that girl over there?  She’s allergic to the eggs in which vaccines are grown and can’t receive them. 
All of these people are susceptible to the illnesses usually prevented by vaccines.  Additionally, vaccines are not 100% effective, meaning even a healthy person who has received a vaccine can get them.

Myth: If vaccines aren't 100% effective, why should I get them?
Vaccination campaigns are hugely successful due to herd immunity, as well as the immunity provided by the vaccine.  When you receive a vaccination and it simulates an immune response your body remembers it.  Just like with a natural infection, sometimes the body doesn’t remember that infections and therefore isn't immune.  This is why someone who has been vaccinated still has a chance of getting sick.  They do however have a much better chance of not getting sick (90-99% depending on the vaccine), and a better chance the infection will be milder.  Saying that vaccinating is a bad idea because it’s not 100% effective is like saying one shouldn't take birth control because you might still get pregnant or not use an umbrella because you can still get wet. 
Herd immunity is when an entire population is immune due to a lack of susceptible individuals.  People can either be non-susceptible (immune) due to previous infection or to vaccination.  The percentage of individuals who must be immune to cause the entire community to be safe through herd immunity depends on the disease in question, due to variance in virulence, infectious period and transmission rate.  Once this level of community immunity has been reached, herd immunity has been reached.  This means there aren’t enough individuals left in the population, and they are separated by social connections, that the disease can’t take hold in the population because it lacks a reservoir (somewhere to stay active).  Many diseases were kept in check for decades with herd immunity.  New disease pockets are immerging because herd immunity in population groups is gone.  Examples include the recent outbreak of measles in New York.  These cases are connected by social groups.  Similar outbreaks can occur in any pocket of non-vaccinated people.   

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