Final answer:
Immune system efficiency does not improve after severe burn injury; it is instead compromised, leading to higher susceptibility to infections, not enhanced immune function.
Step-by-step explanation:
The condition that does not occur as a result of a third-degree (severe) burn is C. Immune system activity becomes efficient within one to two days after severe burn injury. Severe burns, including third-degree burns, cause extensive damage to the skin and underlying tissues, which can lead to a range of serious complications. These include Widespread infection due to the loss of protection by intact layers of skin, Inadequate blood circulation as a result of reduced blood volume, and Catastrophic water loss leading to dehydration and electrolyte imbalances. However, the immune system does not become efficient but is instead compromised, making the body more susceptible to infections.