Question

Exposure to rabies virus can kill a person 2-10 days after symptoms first appear.

A. Why doesn’t antibody production (which is natural immunity) protect and save the person?

B.) How can medicine (artificial immunity) save the person’s life?

Answer 1

A. Natural immunity is the immunity that is naturally existing, it does not require prior sensitization to an antigen. The Immunity is naturally acquired when the body get a viral or bacterial infection during which time the person may develop the symptoms of the disease and suffer. This kind of immunity requires the interaction or the contact with the pathogen, which can only happen when the pathogen enters the body.
Rabies is caused due to lyssaviruses, including the rabies virus and Australian bat lyssavirus (it can be one of them depending on which animal have transmitted it).
In this case At first, rabies induces flu-like symptoms such as weakness, fever, headache, and overall discomfort. The human immune system can fight off the virus if given enough time before Rabies reaches the person’s brain but in most of the cases the time required by the body to interact with virus and protect against it is more and the symptoms are seen eventually which lead to death.
In another words the natural immune system is slow, till the time it reacts with pathogens the person already starts showing the symptoms

B. Artificial immunity is acquired when a person receives vaccines. These vaccines contains dead or attenuated pathogens or their components. They provide two benefits
1. they spare most of the symptoms and discomfort of the disease that would occur in case of primary response.
2. weakened pathogens provide functional antigenic determinants that are both immunogenic and reactive.
When the injections for Rabies are given (before the infection with Rabies or after a bite of an animal where the person have no idea about whether the infection will occur or not) they help the body learn to identify and fight the rabies virus. This type of response is primary when the body encounters the pathogens for the first time, this response take little more time. Antigen‐specific T cells are selected during a primary immune response and expand to produce clones of T cells with high specificity for the activating antigen. In a secondary response to the same antigen, memory cells are rapidly activated. This process is quicker and more effective than the primary response. That is why vaccines can save the life.
On another hand if the person is already infected with Rabies. A fast-acting shot which contains rabies immune globulin or gamma globulin is given to prevent the virus from infecting. This saves the life