Question Regarding Vaccines!

[keithdolby]

Hi,

 

How can an unvaccinated person get a vaccinated person sick? I have heard alot about this lately that unvaccinated people ( not sure if its just children?) have the potentail to spred disease that otherwise would not pop up. For example, how could an unvaccinated child give vaccinated children measels? Not sure if this is a good example, but still am confused on how an unvaccinated person could get a vaccinated person sick. Thanks for the help.

[Cap'n Refsmmat]

It's not that they'll spread it to vaccinated people. It's that they'll spread it to other unvaccinated people. If you have a population with only one unvaccinated kid, the chances of him ever getting sick are tiny -- there's nobody else to give him the illness. But the larger the unvaccinated population the more people there are that can spread the illness to each other, making each unvaccinated person less safe from the disease as the unvaccinated population increases.

[dr.syntax]

There is always a certain amount of uncertainty regarding the effectiveness of any vaccine. Many diseases are capable of rapid mutation and adaptation. Adaptation to survive the anti-bodies produced by the vaccine for instance. Also, many people can be carriers of a disease but have been born with the neccessary defense mechanisms to prevent the disease from expressing itself in those people. They still carry the disease and therefore can infect other people including vaccinated people. Vaccinations do not contain the complete DNA/RNA structures of the disease where as the carrier does with possible portions of which can have evolved a resistance to a vaccine. That`s as much as I can come up with at this time. ...Dr.Syntax

[keithdolby]

WOW! Thanks for the quick replies.

 

Another Question:

 

Person to person diseases develop from somewhere, and is it ever known how the first person comes to develop a given disease? IS it possible to trace back the disease to the orginial person and say yea this person got X disease from Y substance ( like an animal) ? Thanks

[dr.syntax]

and the EBOLA virus. My memory does fail me at times so I am not sure about either one. ....Dr.Syntax

[Cap'n Refsmmat]

WOW! Thanks for the quick replies.

 

Another Question:

 

Person to person diseases develop from somewhere, and is it ever known how the first person comes to develop a given disease? IS it possible to trace back the disease to the orginial person and say yea this person got X disease from Y substance ( like an animal) ? Thanks

This isn't the best Wikipedia article, but it explains the concept decently:

 

http://en.wikipedia.org/wiki/Index_case

 

Epidemiologists do find it useful to try to find the "first" person to have contracted a particular disease to track where it came from and understand its causes.

[GDG]

Hi,

 

How can an unvaccinated person get a vaccinated person sick? I have heard alot about this lately that unvaccinated people ( not sure if its just children?) have the potentail to spred disease that otherwise would not pop up. For example, how could an unvaccinated child give vaccinated children measels? Not sure if this is a good example, but still am confused on how an unvaccinated person could get a vaccinated person sick. Thanks for the help.

 

Sounds to me like someone has inverted the concept of herd immunity. In brief, if you vaccinate nearly all of the population, then even the non-vaccinated individuals are protected, because (in essence) they are surrounded by protected individuals who cannot pass an infection to them. The odds of you coming into contact with an infected individual, and becoming part of the chain of contagion, are much smaller when nearly everyone has been immunized.

 

Only works when the great majority is immunized: if you have a substantial subset who aren't, then no herd immunity.