89. Which one of the following terms is used to describe the protection of the unimmunized individual
based on immunization of a sufficient number of other members of the population?
1. Active immunity
2. Passive immunity
3. Herd immunity
4. Post-exposure immunity

 

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Herd Immunity: Protecting the Unimmunized through Collective Immunization

In the context of infectious diseases and immunization, the term herd immunity refers to the protection of unimmunized individuals within a population when a sufficient proportion of the population is immunized. This collective immunity makes it less likely for the disease to spread, even among those who have not received vaccines.

The Correct Answer: Herd Immunity

The term used to describe the protection of an unimmunized individual based on the immunization of other members of the population is herd immunity.

What is Herd Immunity?

• Herd immunity occurs when a significant portion of the population becomes immune to a disease, either through vaccination or previous infection.

• This widespread immunity reduces the overall amount of the pathogen available to spread, which makes it harder for the disease to propagate, indirectly protecting individuals who are not immune (unimmunized individuals, those who cannot be vaccinated, or those with weakened immune systems).

Herd immunity is particularly important for protecting vulnerable groups such as infants, the elderly, and people with compromised immune systems, who may not be able to receive certain vaccinations.

Other Types of Immunity

1. Active Immunity:

   • Active immunity occurs when an individual’s immune system produces antibodies and memory cells after exposure to a pathogen, either through natural infection or vaccination. This immunity is typically long-lasting.

2. Passive Immunity:

   • Passive immunity involves the transfer of antibodies from one individual to another, such as from mother to child via breast milk or through antibody injections. Unlike active immunity, it provides immediate protection but is temporary.

3. Post-exposure Immunity:

   • Post-exposure immunity refers to the immunity acquired after exposure to a pathogen, often through interventions like post-exposure vaccination or the administration of immune globulin. This immunity works to prevent the disease from developing after an individual has been exposed to the pathogen.

Conclusion

The correct term to describe the protection of unimmunized individuals based on the immunization of others is herd immunity (Option 3). Herd immunity is a cornerstone of public health strategies to control the spread of infectious diseases.

Correct Answer: 3. Herd Immunity