Tuesday, May 01, 2012

Vaccine safety issue

Hello fellows,

         Over a few days, i have been doing some search on vaccines. Like, how they are made, issues related and blah blah blah.... But to my terrifying experience, i found that there is a lot of rumor on the safety of the vaccine issue, which as has been well tackled and explained many times in the weekly podcast- "TWiV".

        I thought, at least as a matter of public interest, I must address this issue. For people who are interested in knowing a little bit about the history of vaccines, click here.

Photo: The arm of Sarah Nelmes, a dairy maid, who had contracted cowpox (Source)

        Ok. Let me get into the point. The question that many people have is "If the vaccines are necessary? What's the risk and benefit? And do I/ my kids need to be vaccinated?". These are some of the fundamental questions addressed here to the best of my knowledge.

         First of all, for dummies, What is vaccines? Vaccines are basically immunity boosters that teaches the immunity that when someone like this is gonna come, you got to act like this (A totally non scientific way of telling, but good for understanding). The vaccines may be live attenuated (Which means its living but no more good enough to cause a pathology), killed vaccines (Self explanatory) and subcomponent vaccines (Only the immunogenic component is used). In any case, the vaccine content is designed to illicit an immune response, but not cause any damage to the maximum possible practical extent.

So,  are vaccines necessary?

          In my (and the large chunk of scientific community) opinion, its YES. For the simple reason that it protects you from various serious conditions simply by training your immune system. The vaccine stimulates a primary immune response and keeps the immune system ready and trained so that when the host encounters the agent again, there is a strong, quick and better response. The basis can be summarized as below.

Fig 1: Primary and Secondary Immunological Responses (For source click here)

            Now, you can easily see what i mean to say. If you are not vaccinated and you encounter the agent, it would take more time and a small response is produced. This gives the pathogen a chance to do more damage. Some argue that why do we need to take as many vaccines as possible if we don't expect to encounter them? The answer is simple. Its more like a Insurance policy. If you are not in trouble, then its a waste of very small (even negligible resource). But if you end up on the wrong side, boy you are in serious no win situation.

What's the risk and benefit?

           I just told about benefit. The risk will be say a 1 in million chances that the live attenuated virus, will revert to its wild form and cause a mild illness Mind you thats a very negligible chance. In fact i would say thats a never to gonna happen chance. Even the antibiotic that we take when we get sick has more chances that it will have a side effect. I happened to read recently that there is more than 10% chance that you will meet with road accidents if you are to drive. Well, if vaccination is hazardous, then i guess we should stop driving. And since most of the modern day vaccines are component vaccines it doesn't carry even the 1 in million chances.

Given the above argument, you should be able to convince any audience and say to then "Hey, don't get you or your near ones into trouble. get them vaccinated." More over there are regulatory bodies that constantly check the safety and efficacy of vaccines.

After all, "Prevention is better than cure"

Further reading:

1. Reports of Health Concerns Following HPV Vaccination (Link)

2. Curlin etal. Integrating Safety and Efficacy Evaluation Throughout Vaccine Research and Development. 
(Click here for link)

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