Herd immunity does not protect an individual in

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2023

Community Health Nursing

Medium

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2023

Explanation

Tetanus is caused by Clostridium tetani, a bacterium found in the environment (soil, dust), not by transmission from another person.
Infection occurs when bacterial spores enter the body through a wound, making it a non-communicable disease.
Herd immunity relies on interrupting a chain of person-to-person infection, a mechanism that is irrelevant for environmentally acquired diseases.
Protection against tetanus is achieved only through individual active immunization with the tetanus toxoid vaccine.

Option A: Diphtheria is a highly contagious bacterial infection spread between people via respiratory droplets. High vaccination rates create herd immunity, which helps protect the entire community.
Option B: Poliomyelitis is a very infectious viral disease transmitted from person to person, primarily through the fecal-oral route. Herd immunity is a cornerstone of polio eradication efforts.
Option C: Smallpox was a contagious viral disease that spread from person to person. Herd immunity, along with surveillance and containment, was critical to its successful eradication.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Herd Immunity and Disease Transmission as background academic context rather than a clinical decision trigger.
A nurse must understand that for tetanus, there is no substitute for individual vaccination. Patient education on maintaining up-to-date tetanus boosters (every 10 years) is a critical preventive health measure.
In a clinical setting, any patient presenting with a break in the skin, from a minor scrape to a deep puncture wound, must have their tetanus immunization status assessed.
What if? A patient presents to the emergency department with a deep, dirty wound from a gardening tool and states they 'had a tetanus shot as a kid' but can't remember when. The nurse's priority action would be to administer both a Tdap/Td vaccine and Tetanus Immune Globulin (TIG) because the vaccination history is uncertain and the wound is high-risk.

How to Approach the Question

First, identify the core concept in the question stem: 'Herd immunity'. Define what this means. Herd immunity protects a community from diseases that spread between people.
Next, note the negative framing: 'does NOT protect'. This means you are looking for the option that is an exception to the rule of herd immunity.
Evaluate each option based on its mode of transmission.
Ask for each disease: 'Does this spread from person to person?'
Diphtheria, Polio, and Smallpox are all contagious. Tetanus is acquired from the environment.
The disease that does not spread from person to person is the one where herd immunity will not apply. This identifies Tetanus as the correct answer.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart B (pp 202-403 of 604) p. 175-177

E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) p. 95-97