They fight viruses and bacteria. These vaccines contain a version of the living virus or bacteria that has been weakened so that it does not cause serious disease in people with healthy immune systems. Because live, attenuated vaccines are the closest thing to a natural infection, they are good teachers for the immune system. Examples of live, attenuated vaccines include measles, mumps, and rubella vaccine (MMR) and varicella (chickenpox) vaccine. Even though they are very effective, not everyone can receive these vaccines. Children with weakened immune systems—for example, those who are undergoing chemotherapy—cannot get live vaccines.
This vaccine is the live virus. It is an injection of a small population of the live virus genetically weakened and is considered a weakened virus. While there is enough of the virus to stimulate an immune response, there isn't enough virus replicating that is actually causes disease.
Using this strategy, (click here) viruses are weakened so they reproduce very poorly once inside the body. The vaccines for measles, mumps, German measles (rubella), rotavirus, oral polio (not used in the U.S.), chickenpox (varicella), and influenza (intranasal version) vaccines are made this way. Viruses usually cause disease by reproducing themselves many times in the body. Whereas natural viruses reproduce thousands of times during an infection, vaccine viruses usually reproduce fewer than 20 times. Because vaccine viruses don't reproduce very much, they don't cause disease, but vaccine viruses replicate well enough to induce "memory B cells" that protect against infection in the future. Find out more about these and other cells of the immune system.
The advantage of live, "weakened" vaccines is that one or two doses provide immunity that is usually life-long. The limitation of this approach is that these vaccines usually cannot be given to people with weakened immune systems (like people with cancer or AIDS).
The advantage of live, "weakened" vaccines is that one or two doses provide immunity that is usually life-long. The limitation of this approach is that these vaccines usually cannot be given to people with weakened immune systems (like people with cancer or AIDS).
HOWEVER, if the virus is attracted to neural pathways, it is far too dangerous to be live attenuated. It MUST be identified as to whether the SARS-CoV-2 virus is a neurological virus or absolutely not.
I don't recall reading a definitive characteristic of this virus in regard to neural pathways. There are bloodshot eyes, brain infarcts, and heart attacks. Are these symptoms brought on by microscopic blood clots and their accumulation in capillaries or is this disease occurring along a neurological path? Is it one of these possibilities OR is it even both? Does this virus attack the neurological pathways as well as the clotting cascade?
If the wild-type virus is neurotropic (click here) or the vaccine has been passaged through neural tissue, health authorities require that an evaluation of neurovirulence during nonclinical development be included in a model capable of distinguishing between wild-type and fully or partially attenuated strains. Small animal models may be acceptable for this purpose provided they are susceptible to wild-type virus. Programs including live attenuated vaccines based on genetically modified organisms also include an environmental risk assessment including the possibility of shedding of vaccine organisms following administration....
