Immunization and Vaccine-Preventable Diseases Practice Questions

Q: An OPV vial shows a specific symbol. What does this symbol indicate?

Use the vaccine if the expiry date has not been reached. ***Use the vaccine if the expiry date has not been reached*** - This describes **VVM Stage 1**, where the **inner square is lighter** than the outer circle, indicating the vaccine can be safely used if within the expiry date. - The **Vaccine Vial Monitor (VVM)** at this stage shows minimal heat exposure and maintains vaccine potency. *The vaccine has reached its expiry date* - **VVM symbols** indicate **heat exposure**, not expiry dates - expiry dates are printed separately on the vial label. - Even if VVM shows Stage 1 (usable), an expired vaccine should never be administered regardless of the VVM reading. *The vaccine has not been stored properly* - **VVM Stage 1** actually indicates **proper cold chain maintenance** with minimal cumulative heat exposure. - Improper storage would show **VVM Stage 3 or 4**, where the inner square becomes equal to or darker than the outer circle. *The vaccine vial is empty* - **VVM symbols** monitor **heat exposure and vaccine potency**, not the physical quantity of vaccine in the vial. - An empty vial would be visually apparent and does not require a specific symbol to indicate.

Q: Which vaccines are not recommended for an 8-year-old unimmunized child?

All of these. ### Explanation The correct answer is **D. All of these**. This question tests the age-specific recommendations and contraindications for vaccines in unimmunized children according to the National Immunization Schedule (NIS) and IAP guidelines. **1. Pertussis (Whole-cell):** The standard DPT vaccine (containing whole-cell Pertussis) is generally not recommended for children above **7 years** of age. This is because the risk of severe systemic reactions and neurotoxicity increases significantly with age. For older children, the acellular version with reduced antigen content (**Tdap**) is preferred. **2. Salk Vaccine (IPV):** In the National Immunization Schedule, IPV is primarily indicated for infants (at 6 and 14 weeks). For an unimmunized child as old as 8 years, the risk-benefit ratio for starting a primary IPV series changes, and it is generally not routinely recommended in mass immunization programs for older children unless they are traveling to endemic areas or are immunocompromised. **3. BCG:** The BCG vaccine is most effective when given at birth. According to the National Health Mission guidelines, BCG can be administered up to **one year of age**. Beyond one year, it is not recommended because most children in endemic countries like India have likely already been exposed to natural *M. tuberculosis* infection, rendering the vaccine ineffective. ### High-Yield Clinical Pearls for NEET-PG: * **BCG Age Limit:** Birth to 1 year (NIS). * **DPT Age Limit:** Up to 7 years. Beyond 7 years, use **Td** (Tetanus and adult-strength Diphtheria) or **Tdap**. * **OPV Age Limit:** Can be given up to 5 years of age. * **Measles/MR Age Limit:** Can be given up to 5 years under NIS (though IAP suggests it can be given later if missed). * **Catch-up Vaccination:** Always check the upper age limit for each vaccine; for example, the Hepatitis B vaccine can be given at any age if not previously immunized.

Q: Which of the following statements about the Yellow Fever Vaccine is FALSE?

The route of administration is intramuscular.. **Explanation:** The correct answer is **D** because the **Yellow Fever vaccine (17D strain)** is administered via the **subcutaneous route**, not intramuscularly. This is a high-yield distinction in NEET-PG, as most live vaccines (like MMR and Yellow Fever) are given subcutaneously. **Analysis of Options:** * **A. It is a live attenuated vaccine:** This is **true**. It is prepared from the 17D strain of the virus, grown in chick embryos. It is highly effective, providing immunity in 99% of recipients within 10 days. * **B. Reconstitution is with cold physiological saline:** This is **true**. Unlike the BCG vaccine (normal saline) or Measles (sterile water), Yellow Fever vaccine must be reconstituted with cold, sterile physiological saline and used within 30 minutes. * **C. The dose is 0.5 ml:** This is **true**. The standard dose for both adults and children (above 9 months) is 0.5 ml. **High-Yield Clinical Pearls for NEET-PG:** * **Validity:** The International Certificate of Vaccination becomes valid **10 days** after vaccination and, as per recent WHO amendments, is now valid for the **lifetime** of the individual. * **Contraindications:** It is contraindicated in infants **<6 months**, pregnant women (unless in high-risk outbreaks), and individuals with **egg allergies** or thymic disorders. * **Storage:** It must be stored between **-30°C and +5°C** (ideally in the freezer compartment). * **Quarantine:** If an unvaccinated traveler arrives from a Yellow Fever endemic zone, they are subject to quarantine for **6 days**.

Q: The 23-valent pneumococcal polysaccharide vaccine is recommended in all of the following conditions except?

Children less than 2 years of age. ### Explanation The **23-valent Pneumococcal Polysaccharide Vaccine (PPSV23)** contains purified capsular polysaccharides. The core immunological principle here is that polysaccharide antigens are **T-cell independent**. **1. Why Option C is correct:** In children **less than 2 years of age**, the immune system (specifically the splenic marginal zone) is immature and cannot mount an effective immune response to T-cell independent antigens. Therefore, PPSV23 is **ineffective and not recommended** in this age group. For children under 2, the **Pneumococcal Conjugate Vaccine (PCV)** is used instead, as it attaches the polysaccharide to a protein carrier, making it T-cell dependent and immunogenic in infants. **2. Analysis of Incorrect Options:** PPSV23 is indicated for "high-risk" individuals aged 2 years and older who are at increased risk of invasive pneumococcal disease (IPD): * **Option A (CSF Leak):** This is a high-risk condition as it provides a direct pathway for bacteria to cause meningitis. * **Option B (Chronic Cardiac Disease):** Conditions like congestive heart failure or cardiomyopathies increase vulnerability to severe pneumonia. * **Option D (Nephrotic Syndrome):** This is an immunocompromised state characterized by the loss of antibodies and complement factors in urine, significantly increasing the risk of pneumococcal infection. **High-Yield Clinical Pearls for NEET-PG:** * **PCV (e.g., PCV13):** Given in the National Immunization Schedule at 6 weeks, 14 weeks, and a booster at 9 months. * **PPSV23:** Does not produce mucosal immunity or herd immunity and does not induce immunological memory (unlike PCV). * **Sequential Vaccination:** In high-risk adults, PCV is often given first, followed by PPSV23 after an interval (usually 8 weeks to 1 year) to broaden serotype coverage. * **Asplenia/Sickle Cell Anemia:** These are the highest-yield indications for PPSV23 in patients >2 years old.

Q: At what age is the Rubella vaccine typically administered?

1-14 years. **Explanation:** The Rubella vaccine (often administered as the MR or MMR vaccine) is primarily targeted at children and adolescents to prevent **Congenital Rubella Syndrome (CRS)**. **Why Option A is Correct:** In the context of public health campaigns and the National Immunization Schedule (NIS) in India, the MR (Measles-Rubella) vaccination campaign specifically targets children aged **9 months to 15 years (effectively the 1-14 years age group)**. The goal is to build herd immunity and eliminate the virus from the community, thereby protecting pregnant women from infection, which can lead to severe fetal anomalies (CRS). Under the routine NIS, the first dose is given at 9-12 months and the second at 16-24 months. **Why Other Options are Incorrect:** * **Option B (Under 5 years):** While children under 5 receive the vaccine during routine immunization, limiting it to this age group would leave a significant "immunity gap" in older children who can still transmit the virus to susceptible pregnant women. * **Option C (Over 50 years):** Rubella is typically a mild childhood illness. Vaccination in the elderly is not a public health priority as most adults are already immune through natural exposure or prior vaccination. **High-Yield NEET-PG Pearls:** * **Type of Vaccine:** Live attenuated (RA 27/3 strain is most common). * **CRS Triad:** Cataract, Sensorineural deafness, and Congenital Heart Disease (most commonly Patent Ductus Arteriosus). * **Contraindication:** Pregnancy (due to theoretical risk to the fetus). Women are advised to avoid pregnancy for **1 month** (formerly 3 months) after vaccination. * **Storage:** It is heat-sensitive and must be stored at +2°C to +8°C and protected from light.

Question 1

Which of the following is NOT a strategy for measles elimination?

Accepted Answer

Mop up: Vaccinate children missed during routine vaccination.

Answer

Catch up: One-time nationwide vaccination of children aged 9 months to 14 years.

Answer

Keep up: Vaccinate over 95% in successive birth cohorts.

Answer

Follow up: Nationwide vaccination every 2-4 years.

Question 2

An OPV vial shows a specific symbol. What does this symbol indicate?

Accepted Answer

Use the vaccine if the expiry date has not been reached

Answer

The vaccine has reached its expiry date

Answer

The vaccine has not been stored properly

Answer

The vaccine vial is empty

Question 3

Which vaccines are not recommended for an 8-year-old unimmunized child?

Accepted Answer

All of these

Answer

Pertussis

Answer

Salk vaccine

Answer

BCG

Question 4

Which of the following are components of acellular pertussis vaccine?

Accepted Answer

Pertussis toxin (PT) + Filamentous hemagglutinin (FHA) + Fimbriae

Answer

Pertussis toxin (PT) + Cytotoxin + Fimbriae

Answer

Endotoxin + Fimbriae + Pili

Answer

Peactin + Filamentous hemagglutinin (FHA) + Outer membrane protein (OMP) + Fimbriae

Question 5

Which of the following statements about the Yellow Fever Vaccine is FALSE?

Accepted Answer

The route of administration is intramuscular.

Answer

It is a live attenuated vaccine.

Answer

Reconstitution is with cold physiological saline.

Answer

The dose is 0.5 ml.

Question 6

The 23-valent pneumococcal polysaccharide vaccine is recommended in all of the following conditions except?

Accepted Answer

Children less than 2 years of age

Answer

Cerebrospinal fluid leak

Answer

Chronic cardiac disease

Answer

Nephrotic syndrome

Question 7

Which of the following require post-exposure immunization?

Accepted Answer

Chickenpox

Answer

Measles

Answer

Polio

Answer

Rabies

Question 8

At what age is the Rubella vaccine typically administered?

Accepted Answer

1-14 years

Answer

Under 5 years

Answer

Over 50 years

Answer

None of the above

Question 9

Which of the following statements is true about the pneumococcal vaccine?

Accepted Answer

It is not given in splenectomy patients.

Answer

It is not given if the age is less than 2 years.

Answer

It is polyvalent.

Answer

It is derived from capsular protein.

Question 10

At what temperature should the measles vaccine be stored at a primary health centre?

Accepted Answer

+2°C to 8°C

Answer

-20°C

Answer

0°C

Answer

Any temperature not exceeding room temperature

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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