Category Archives: Vaccine Immunology

Vaccines 101

When a germ such as a virus or bacteria enters your body, your immune system goes into battle. It makes antibodies that locate the germ and launches an attack to fight it off.

After the antibodies have attacked they stick around in the body to protect you if the same germ enters your body again.

Often the antibodies can stop an infection by the remembered germ should it enter your body again. The infection is stopped before you even show signs of being sick! Continue reading

Why do we need booster shots?

You’d think most vaccines would leave you protected from the disease for life, right? While some vaccines do have very long-lasting immunity to disease, certain vaccines need to be given more than once to make sure the body has that long-lasting protection. Vaccinations like these need to be given more than once to yield full protection from disease. These extra shots are called BOOSTERS.

The immune system needs to create memory cells that will recognize the pathogen should it enter the body. To do that the immune system needs to “see” the pathogen at least once and make antibodies necessary to fight it off. Once this happens, the immune system’s memory cells keep that pathogen in it’s memory banks, so to speak. How cool is that? The immune system is so darn amazing, isn’t it?

So the initial vaccination dose activates an immune response in the body so that memory cells are created. Sometimes this is all the body needs. But in some cases, additional doses of a vaccine might be needed periodically to “boost” the immune system’s memory of the disease. Continue reading

Viral Vaccine Immunology

What happens after you are injected with a viral vaccine? And which viral vaccine type is best?

(Note that I’m going to be talking about viral vaccines ONLY.)

First of all, there two basic types of viral vaccines: live attenuated vaccines (LAV) and inactivated (killed) vaccines.

LAV contain a vaccine virus that is a weakened version of the natural disease-causing virus. Inactivated vaccines use a killed version or a part(s) of the natural virus.

The body’s response to the vaccine virus in relation to the natural disease-causing virus has to do with the type of vaccine being administered, as well as how similar the vaccine virus is to the natural virus.

I’m going to go ahead and stop saying “vaccine virus”, and start calling this the “antigen”. An antigen is something foreign (in this case) that the body makes an immune response to, or something that’s the target for an immune response.

An inactivated vaccine contains all of the antigen needed to induce an immune response in the injected dose. Once it is injected into the muscle, the immune system begins to respond to this antigen. The LAV works a bit differently. There is only a very tiny amount of live weakened virus, and it must use the host body’s cells to reproduce in order to create the proper immune response. Once a LAV is injected into the muscle, the antigen migrates to the appropriate tissue in order to begin replication. The “appropriate tissue” in this case would be the tissue the natural virus would normally infect and replicate in.

Because the vaccine virus is so similar to the natural virus in LAV, these vaccines create an immune response virtually identical to the natural infection. The inactivated vaccine’s response is similar, yet one drawback is that immune stimulation occurs at the site of injection and not at the site of natural viral replication.

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