I just did some very quick research on whether a virus is living or not. You're right it's under debate (not decided), but determining this seems to be important for the theory of evolution. My personal views don't let me consider evolution, only a divine creator so I don't know much about this. So maybe the modified live vaccine is not technically alive according to the scientific defintion of life, but once it joins with a cell it has attributes of life.
From canismajor.com
Which is better, killed virus vaccines or modified-live types?
Each type of vaccine has strengths and weaknesses. Modified-live vaccines provide stronger, longer-lasting, and more rapid protection, including local immunity. They are less expensive and may require only one dose to be effective. They have a potential to become active and cause disease, especially in a patient with a weakened immune system; to create immunosuppression, or to cause abortions in pregnant dogs. Careful handling and storage are required to prevent breakdown of the active ingredients.
Killed vaccines cannot become virulent and are less likely to be immunosuppressive or cause abortions. They remain stable during storage. They are more likely to cause allergic reactions, require more initial injections and more frequent booster shots, and do not produce local immunity.
A good example of the differences between modified-live and killed vaccines is the use of Bordatella vaccinations for kennel cough. Killed vaccines require two injections but are only 60-80 percent effective against disease and don't provide local immunity at the level of the airway. Modified- live vaccines are given intranasally, require only one dose, and start providing local immunity within 48 hours. |