Variables Affecting Success Rates of Vaccines

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  • 0:01 Vaccines Save Lives
  • 1:09 General Health
  • 2:24 Method and Timing
  • 4:04 Lesson Summary
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Lesson Transcript
Instructor: Sarah Friedl

Sarah has two Master's, one in Zoology and one in GIS, a Bachelor's in Biology, and has taught college level Physical Science and Biology.

Vaccines can help your body learn how to fight infection and disease. However, there are certain factors that affect how effective that vaccine will be. In this lesson, we'll discuss what might influence the success rate of a vaccine and why.

Vaccines Save Lives

Vaccines are a hot topic these days. Some people swear by their annual flu shot, while others are proposing that childhood vaccines may have serious side effects and advocate against them. No matter what side of the fence you may be on, simply put, vaccines do save lives. Things like polio, smallpox, and measles have been all but eradicated in most developed countries, thanks to vaccines.

You may recall that a vaccine is a harmless variant or small part of a disease-causing agent that stimulates the immune system to attack it. What this does is give your immune system a 'memory' of that disease so that if you encounter the real thing in the future, that internal army of yours has the ability to fight it off. Some things our body naturally knows how to fight off. But others, like malaria and tetanus, we have to 'trick' our body into fighting because it doesn't naturally know how to do so.

But just like not all people who get vaccines are the same, neither are the vaccines they receive. There are several factors that influence how successful a vaccination will be in a person or group of people; let's discuss them in a bit more detail to see why.

General Health

One factor that influences how successful a vaccine will be is your general health. Take the flu shot for example. The Centers for Disease Control and Prevention, or CDC, suggests that the flu vaccine will be most effective for healthy adults and children over 6 months of age (babies younger than this are simply too young to receive this vaccination). Why this group of people?

It makes sense that those who are in poor health in general are less likely to see a successful effect from the vaccine. When you are sick, your immune system is already busy fighting off other diseases and is working overtime to get you back to feeling normal. If you get vaccinated during this state, your immune system can't devote itself to fighting off this new 'intruder'. So even though you received the vaccine, the chance that your immune system will fully recognize it and defend against it in the future is lowered.

In addition to general health, your stress level will also play an important role in the success of a vaccination. When you are stressed, your hormone levels change and this, in turn, changes how your immune system functions. High levels of stress can significantly suppress your body's defense system, and getting a vaccination during this time may reduce the ability for your immune system to attack it.

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