Vaccination Principles — MCQs
Mass vaccination is ineffective in inducing 'herd immunity' for:
Adverse reactions following whole cell pertussis immunization include:
Which of the following vaccines is classified as a killed vaccine?
Assertion: VZV vaccine is live attenuated. Reason: It cannot be given to immunocompromised patients.
All of the following statements about MMR vaccine are true EXCEPT:
All the following are conjugate vaccines Except
Which immunization is typically given at 6 months of age?
Which route is the H1N1 live vaccine administered by?
What is the schedule of intradermal rabies vaccine?
A young male came to the hospital with a clean-cut wound without any bleeding. The patient received a full course of tetanus vaccination 10 years ago. What is the best management for this patient?
Vaccination Principles Indian Medical PG Practice Questions and MCQs
Question 1: Mass vaccination is ineffective in inducing 'herd immunity' for:
- A. Poliomyelitis
- B. Tetanus (Correct Answer)
- C. None of the options
- D. Measles
Explanation: ***Tetanus (Correct Answer)*** - **Herd immunity** relies on reducing person-to-person transmission, which is not applicable to tetanus as it is acquired through **environmental exposure** (soil contaminated with *Clostridium tetani* spores), not human contact - Vaccination against tetanus provides **individual protection only** and does not prevent disease spread within a population, making mass vaccination ineffective for herd immunity - Tetanus is a **non-communicable disease** - immunity in others does not protect unvaccinated individuals *Poliomyelitis (Incorrect)* - Mass vaccination for poliomyelitis has been highly effective in establishing **herd immunity**, leading to near-global eradication - The vaccine prevents viral shedding and breaks the chain of transmission - High vaccination coverage protects unvaccinated individuals through reduced viral circulation *Measles (Incorrect)* - Mass vaccination against measles is extremely effective in inducing **herd immunity** due to its high transmissibility (R₀ = 12-18) - Requires **~95% vaccination coverage** to maintain herd immunity - Classic example where high vaccination rates protect vulnerable individuals who cannot be vaccinated *None of the options (Incorrect)* - This is incorrect because tetanus is a clear example where mass vaccination does **not** induce herd immunity - The disease's environmental transmission pattern makes herd immunity irrelevant for disease control
Question 2: Adverse reactions following whole cell pertussis immunization include:
- A. Fever
- B. Local swelling
- C. Excessive cry
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Whole-cell pertussis vaccines** are associated with a range of common, generally self-limiting adverse reactions. - These include systemic effects like **fever** and irritability, often manifested by excessive crying, as well as local reactions at the injection site. *Fever* - **Fever** is a very common systemic adverse reaction following whole-cell pertussis immunization, indicating the body's immune response. - This reaction typically resolves within 24-48 hours. *Excessive cry* - **Excessive crying** (often described as inconsolable crying) for several hours is a known systemic adverse effect of whole-cell pertussis vaccines. - This symptom usually reflects irritability and discomfort experienced by the infant. *Local swelling* - **Local swelling** at the injection site, along with redness and tenderness, is a frequent local adverse reaction to whole-cell pertussis immunization. - These local reactions are generally mild and self-limiting, resolving within a few days.
Question 3: Which of the following vaccines is classified as a killed vaccine?
- A. Varicella
- B. BCG
- C. OPV
- D. Meningococcal vaccine (Correct Answer)
Explanation: ***Meningococcal vaccine*** - The meningococcal conjugate and polysaccharide vaccines are **killed vaccines**, containing inactivated bacterial components (polysaccharides) that stimulate an immune response. - They provide protection against *Neisseria meningitidis* and are considered safe for most populations due to their non-live nature. *Varicella* - The varicella vaccine is a **live-attenuated vaccine**, meaning it contains a weakened form of the **varicella-zoster virus**. - This attenuated virus can replicate in the recipient, eliciting a strong and long-lasting immune response, similar to natural infection. *BCG* - The **Bacillus Calmette-Guérin (BCG)** vaccine is a **live-attenuated vaccine** used to prevent tuberculosis. - It contains a weakened strain of **_Mycobacterium bovis_**, which is closely related to *Mycobacterium tuberculosis* but has lost its virulence. *OPV* - The **Oral Polio Vaccine (OPV)** is a **live-attenuated vaccine** that contains weakened but live strains of all three poliovirus serotypes. - It induces strong mucosal immunity in the gut, which is crucial for preventing the wild poliovirus from replicating and spreading.
Question 4: Assertion: VZV vaccine is live attenuated. Reason: It cannot be given to immunocompromised patients.
- A. Both true, reason doesn't explain assertion
- B. Assertion true, reason false
- C. Assertion false, reason true
- D. Both true, reason explains assertion (Correct Answer)
Explanation: ***Both true, reason explains assertion*** - The **VZV (varicella-zoster virus) vaccine** is indeed a **live attenuated vaccine** containing weakened virus - the assertion is **TRUE** - It **cannot be given to immunocompromised patients** due to risk of vaccine-strain disease - the reason is **TRUE** - The reason **directly explains the assertion**: BECAUSE the vaccine is live attenuated, it poses infection risk and therefore cannot be used in immunocompromised individuals - The **causal relationship** is clear: live attenuated nature → contraindication in immunocompromised patients *Both true, reason doesn't explain assertion* - While both statements are factually true, this option would only be correct if the reason was unrelated to the assertion - However, the reason **directly explains WHY** the live attenuated nature is clinically significant - The contraindication is a **direct consequence** of the vaccine being live attenuated, so the reason does explain the assertion *Assertion true, reason false* - The assertion is true (VZV vaccine is live attenuated) - However, the reason is also **TRUE** - live attenuated vaccines are indeed contraindicated in immunocompromised patients due to risk of disseminated vaccine-strain infection - Since both statements are true, this option is incorrect *Assertion false, reason true* - The assertion is **TRUE**, not false - VZV vaccine (Varivax, Zostavax) is a **live attenuated vaccine** containing the Oka strain - This option incorrectly claims the assertion is false - Since the assertion is factually correct, this option cannot be right
Question 5: All of the following statements about MMR vaccine are true EXCEPT:
- A. All live vaccines without exception are contraindicated in pregnant women (Correct Answer)
- B. MMR is a live vaccine
- C. Adverse events from MMR vaccine include fever (usually 6-12 days following vaccination), rash in 5% of vaccinated persons, arthralgia, aseptic meningitis, lymphadenopathy
- D. Evidence shows that aseptic meningitis is associated with all mumps vaccine strains except the Jeryl Lynn strain
Explanation: ***Correct Answer: All live vaccines without exception are contraindicated in pregnant women*** - This statement is **FALSE**, making it the correct answer to this EXCEPT question - While **most live vaccines are contraindicated in pregnancy** (including MMR), the word **"without exception"** makes this statement incorrect - **Exceptions exist**: Yellow fever vaccine may be administered during pregnancy if travel to endemic areas is unavoidable and the risk of disease outweighs the theoretical vaccine risk - The absolute nature of this statement contradicts clinical guidelines that recognize situational exceptions *True Statement - MMR is a live vaccine* - **MMR vaccine** contains **live-attenuated viruses** of measles, mumps, and rubella - This live-attenuated nature produces robust, long-lasting immunity - Being a live vaccine necessitates contraindications in immunocompromised patients and pregnant women *True Statement - Adverse events from MMR vaccine* - **Fever** typically occurs **6-12 days post-vaccination** (not immediately), reflecting viral replication - **Rash** occurs in approximately **5% of vaccinees** - Other documented adverse events include **arthralgia** (especially in adult women), **aseptic meningitis** (rare), and **lymphadenopathy** - These adverse events are far less severe than complications from natural measles, mumps, or rubella infection *True Statement - Aseptic meningitis and vaccine strains* - **Urabe** and **Leningrad-Zagreb** mumps vaccine strains have been associated with higher rates of vaccine-associated **aseptic meningitis** (approximately 1 in 100,000 to 1 in 1 million doses) - The **Jeryl Lynn strain** (used in the United States and many other countries) has **negligible or no association** with aseptic meningitis - This safety profile makes the Jeryl Lynn strain the preferred mumps component in MMR vaccines
Question 6: All the following are conjugate vaccines Except
- A. Neisseria meningitidis
- B. Haemophilus influenzae type b
- C. Hepatitis A (Correct Answer)
- D. Pneumococcal
Explanation: ***Hepatitis A (Correct Answer)*** - The **Hepatitis A vaccine** is a **killed viral vaccine** (inactivated vaccine), meaning it contains whole hepatitis A virus particles that have been inactivated so they cannot replicate or cause disease. - It is **NOT a conjugate vaccine** - inactivated vaccines primarily induce a **humoral immune response** without the need for a carrier protein conjugated to a polysaccharide. - This makes Hepatitis A the exception among the options listed. *Neisseria meningitidis (Incorrect)* - The most common vaccines against *Neisseria meningitidis* are **conjugate vaccines**, where the **polysaccharide capsule** is chemically linked to a protein carrier to enhance immunogenicity in infants and young children. - This conjugation allows for T-cell dependent immunity, leading to better memory responses and protection. *Haemophilus influenzae type b (Incorrect)* - The **Haemophilus influenzae type b (Hib) vaccine** is a **conjugate vaccine**, linking the **polysaccharide capsule** of the bacterium to a carrier protein. - This helps induce a robust T-cell dependent immune response, which is crucial for protecting infants and young children against **invasive Hib disease**. *Pneumococcal (Incorrect)* - **Pneumococcal conjugate vaccines** (PCV13, PCV15, PCV20) link the **polysaccharide capsule** to a protein carrier, enhancing immunogenicity and memory, especially in young children. - While polysaccharide vaccines (PPSV23) also exist, the conjugate forms are the primary vaccines used in routine immunization schedules.
Question 7: Which immunization is typically given at 6 months of age?
- A. Measles vaccine
- B. DPT vaccine (Correct Answer)
- C. BCG vaccine
- D. None of the options
Explanation: **DPT vaccine** - The DPT (diphtheria, pertussis, and tetanus) vaccine is administered in multiple doses during infancy as part of the primary immunization series. - At **6 months of age**, the **third dose of DPT** is typically given (following doses at 6 weeks, 10 weeks, and 14 weeks according to the Indian immunization schedule). - Among the options provided, DPT is the only vaccine routinely administered at 6 months of age. - This vaccine protects against three serious bacterial infections: **diphtheria**, which can cause breathing problems; **pertussis (whooping cough)**, a severe respiratory illness; and **tetanus**, which causes painful muscle spasms. *Measles vaccine* - The measles vaccine (given as part of the **MMR vaccine** or as MR vaccine in India) is typically administered at **9 to 12 months of age** for the first dose, and a second dose between 15-18 months or 4-6 years. - It is not routinely given at 6 months, as maternal antibodies can interfere with its effectiveness at this younger age. *BCG vaccine* - The BCG (Bacillus Calmette-Guérin) vaccine protects against **tuberculosis** and is given at **birth** or in early infancy as a single dose. - It is not administered at 6 months of age. *None of the options* - This option is incorrect because the **DPT vaccine** (third dose) is a standard immunization given at 6 months of age according to the Indian immunization schedule. - Multiple vaccines are actually given at 6 months (including OPV, Hepatitis B, Hib, PCV), but among the listed options, only DPT is correct.
Question 8: Which route is the H1N1 live vaccine administered by?
- A. Intramuscular
- B. Intranasal (Correct Answer)
- C. Oral
- D. Subcutaneous
Explanation: ***Intranasal*** - The **live attenuated influenza vaccine (LAIV)**, often referred to as the "nasal spray flu vaccine," is administered intranasally. - This route allows the vaccine to replicate in the **nasal passages**, mimicking natural infection and stimulating a localized immune response. *Intramuscular* - The **inactivated influenza vaccine (IIV)**, or the "flu shot," is administered intramuscularly. - This route delivers the vaccine into the **muscle tissue** to stimulate a systemic immune response without local replication. *Subcutaneous* - Subcutaneous administration is used for some vaccines, but it is **not the standard route** for either live or inactivated influenza vaccines. - This route delivers the vaccine into the **fatty tissue** just under the skin. *Oral* - Oral administration is typically used for live vaccines that need to replicate in the **gastrointestinal tract**, such as the rotavirus vaccine. - It is **not an appropriate route** for influenza vaccines as the virus needs to stimulate respiratory immunity.
Question 9: What is the schedule of intradermal rabies vaccine?
- A. 2-2-0-1-0-1
- B. 8-4-4-1-0-1
- C. 2-2-2-0-1-1
- D. 2-0-2-0-1-1 (Correct Answer)
Explanation: ***2-0-2-0-1-1*** - This schedule represents the **Thai Red Cross (TRC) regimen** for intradermal rabies vaccination that was standard at the time of this exam (2013). - The numbers indicate the number of vaccine doses administered at different sites: **2 doses on day 0** (bilateral deltoids), **0 doses on day 3**, **2 doses on day 7** (bilateral deltoids), **0 doses on day 14**, **1 dose on day 28**, and **1 dose on day 90**. - This was the **answer expected for NEET 2013** based on the guidelines prevalent at that time. - **Note:** Current WHO guidelines (post-2013) recommend the updated 2-2-2-0-1-1 schedule (4-site ID regimen) which includes doses on days 0, 3, 7, and 28. *2-2-0-1-0-1* - This schedule is **not a recognized** intradermal rabies vaccination protocol. - Does not match any standard WHO-approved regimen for intradermal administration. *2-2-2-0-1-1* - While this may appear incorrect for the 2013 exam context, this schedule actually represents the **current updated Thai Red Cross (4-site ID) regimen** recommended by WHO in recent guidelines. - This regimen provides doses on **days 0, 3, 7, 28, and 90**, which is now the preferred intradermal schedule. - However, for the NEET 2013 exam, the older 2-0-2-0-1-1 schedule was the expected answer. *8-4-4-1-0-1* - This schedule is **not a standard regimen** and involves an impractically high number of doses. - No recognized intradermal rabies protocol uses this many doses on initial days. - Would be **unnecessary and impractical** for effective post-exposure prophylaxis.
Question 10: A young male came to the hospital with a clean-cut wound without any bleeding. The patient received a full course of tetanus vaccination 10 years ago. What is the best management for this patient?
- A. Single-dose tetanus toxoid (Correct Answer)
- B. Human tetanus immunoglobulin only
- C. Human tetanus immunoglobulin and a full course of vaccine
- D. No treatment required
Explanation: ***Single-dose tetanus toxoid*** - For a **clean-cut wound** in a patient who completed a **primary tetanus vaccination series** and received their last dose more than 5 years ago but less than 10 years ago, a **single booster dose** of tetanus toxoid is recommended. [1] - A booster ensures continued protection, as vaccine-induced immunity wanes over time, but the prior full course provides a robust anamnestic response with a single dose. *Human tetanus immunoglobulin and a full course of vaccine* - This regimen (tetanus immunoglobulin + vaccine) is typically reserved for patients with **unvaccinated status**, an **unknown vaccination history**, or a **severely contaminated wound** (e.g., rusty nail, soil contamination) who have not been fully vaccinated. - The patient had a **clean-cut wound** and completed a full course of vaccination 10 years ago, making immunoglobulin unnecessary and a full course of vaccine excessive. *Human tetanus immunoglobulin only* - Administering **tetanus immunoglobulin alone** is appropriate for immediate, passive immunity in situations where a patient is unvaccinated or has an unknown vaccination status and has a significant risk of tetanus from a contaminated wound. [2] - This patient has a clean wound and a history of full vaccination, so a booster is sufficient to stimulate active immunity. *No treatment required* - While the patient was fully vaccinated 10 years ago, the protection from tetanus vaccination can **wane over time**, especially after 5-10 years. - A **booster dose** is crucial to maintain adequate protection against tetanus, even for a clean wound, given the 10-year interval since the last dose.
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