phases.That means the subsequent doses boost immunity to reach a certain protection level. In comparison, live vaccines contain some amount of live disease antigen which goes inside the body to spread and reproduce.One single dose is enough to build immunity in most children. However, a second dose is administered since some children do not develop immunity from the first dose. 04 Are some of the vaccine ingredients toxic? Given at a very high dose, any substance, even water, can be toxic. Some vaccine ingredients can be harmful only if present in a high amount. However, at low doses, such substances are safe. 30
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