vaccination 101
since flu is an issue of the moment
What a vaccine does is introduce your body to parts of the outside coating of whatever you're vaccinating against, so that your body will be prepared to recognize and attack the real thing when it comes around.
Once upon a time, in the early days of vaccination, one fairly common method was to actually infect people with a similar bug, or a weakened version of the pathogenic bug. This has not been done in the US for a long time. These days they use antigens (anything that can produce a specific immune response) which the bug has, but well-separated from any live bug.
When your immune system is exposed to a new antigen, it gears up the machinery to fight off an intruder. Specifically, a particular set of white blood cells wake up and start working on making antibodies to the new antigens.
This can cause your lymph nodes to be unhappy because they are where the work is going on. Often your body will run a bit of a fever too, which is another first-response defense against a wide range of possible attacking agents, and you will get the whole set of things you usually get when you're coming down with something, because your body is on red alert from a big dose of something that looks scary.
If you're wiped out to start with, you can also be weakened enough by the extra stress to lose the battle with some live pathogen that's attacking you at the same time, and people who are at high risk for that are among the ones who should be careful with vaccinations. (The others that I'm aware of are those prone to extreme allergies, which is a different rant.)
But in a healthy person, what happens is that the body fires up the white blood cells and they tool up the right code to produce antibodies to the new antigen. This takes about two weeks the first time the system sees a given antigen, and can be called into use basically immediately thereafter, as fast as the body can reproduce the cells with the right code.
Which is the value of a vaccine: if your body does not get the advance warning, then the whole time it is trying to get through the process to build the right tool to fight the new bug, the bug only has to deal with the non-specific immune response. Which is not enough to kill a really virulent bug.
And with a virus, you can't use antibiotics to get at it, so a well-primed antibody response is your best defense.
(wanna hear why the flu is such a perennial problem? It's a cool weird tale, if you like that sort of thing...)
What a vaccine does is introduce your body to parts of the outside coating of whatever you're vaccinating against, so that your body will be prepared to recognize and attack the real thing when it comes around.
Once upon a time, in the early days of vaccination, one fairly common method was to actually infect people with a similar bug, or a weakened version of the pathogenic bug. This has not been done in the US for a long time. These days they use antigens (anything that can produce a specific immune response) which the bug has, but well-separated from any live bug.
When your immune system is exposed to a new antigen, it gears up the machinery to fight off an intruder. Specifically, a particular set of white blood cells wake up and start working on making antibodies to the new antigens.
This can cause your lymph nodes to be unhappy because they are where the work is going on. Often your body will run a bit of a fever too, which is another first-response defense against a wide range of possible attacking agents, and you will get the whole set of things you usually get when you're coming down with something, because your body is on red alert from a big dose of something that looks scary.
If you're wiped out to start with, you can also be weakened enough by the extra stress to lose the battle with some live pathogen that's attacking you at the same time, and people who are at high risk for that are among the ones who should be careful with vaccinations. (The others that I'm aware of are those prone to extreme allergies, which is a different rant.)
But in a healthy person, what happens is that the body fires up the white blood cells and they tool up the right code to produce antibodies to the new antigen. This takes about two weeks the first time the system sees a given antigen, and can be called into use basically immediately thereafter, as fast as the body can reproduce the cells with the right code.
Which is the value of a vaccine: if your body does not get the advance warning, then the whole time it is trying to get through the process to build the right tool to fight the new bug, the bug only has to deal with the non-specific immune response. Which is not enough to kill a really virulent bug.
And with a virus, you can't use antibiotics to get at it, so a well-primed antibody response is your best defense.
(wanna hear why the flu is such a perennial problem? It's a cool weird tale, if you like that sort of thing...)