How
do vaccines work?
Vaccines:
-
Imitate natural disease exposure
-
Prime specific cells within the immune system
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"Stimulate" immune cell memory, so when disease strikes, the immune system responds strongly and quickly
Modified-live
viral vaccines:
-
Stimulate a stronger and more complete immune response than killed vaccines
-
Contain altered viruses that replicate and stimulate the immune system, but do not cause disease
-
Stimulate local, humoral (antibodies) and cell-mediated (killer cells) immunity
-
Often require only one dose
Temperature-specific modified-live viral
vaccines:
-
Contain chemically altered viruses that have limited replication at normal body temperature; enough to create a strong immune response but don't cause disease.
-
Safe for use in pregnant cows and calves nursing pregnant cows
Killed vaccines
-
Contain inactivated virus that cannot replicate in the body
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Stimulate primarily humoral immunity (antibodies)
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Often require two doses