Active immunity refers to the activation of an individual’s adaptive immune defenses. This type of immunity can be acquired through natural exposure to the disease-causing agent (such as an infection) or through vaccination.

Active Immunity 

Passive immunity refers to the transfer of antibodies from another individual or animal. Passive immunity can be described in 2 ways:
 - Artificial Passive Immunity
 - Natural Passive Immunity

Passive Immunity

Adaptive immunity can be classified as either active or passive immunity.

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Adaptive immunity is defined by two important characteristics: specificity and memory. Specificity refers to the adaptive immune system’s ability to target specific pathogens, and memory refers to its ability to quickly respond to pathogens to which it has previously been exposed. These elements synergistically work with the innate response in order to completely control antigens.

Adaptive Immune Response

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Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

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- B-Cell Immunity in COVID-19
- T-Cell Immunity in COVID-19
Adaptive response process
- Blood brings the cells throughout the body as normal where the B cells are working alongside t cells to go into the plasma where they produce antibodies specific to the antigen.  
- A neutralizing antibody is efficient in fully blocking the virus from entering the host cells. This helps limit the infection and relapse. 
- The overall adaptive immune response is directed by helper T cells, and cytotoxic T cells play a vital role in the clearance and cleaning of viral-infected cells
- Adaptive immune response against coronavirus requires stimulation of B cell and T cell epitopes


Adaptive Immune Response to COVID-19

**Specificity** and **memory** are achieved by  programming certain cells in the immune response to respond rapidly to exposures of the pathogen. This programming occurs as a result of the first exposure to a pathogen or vaccine, which triggers a **primary response**.    

Primary Response of the Adaptive Immune System

There are two branches of the adaptive immune system:
- Humoral Immunity
- Cellular Immunity

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