Immunization and Vaccine-Preventable Diseases Practice Questions

Q: Immunization with Rotavirus should be completed by what age?

12 months. ### Explanation **Correct Answer: C. 12 months** In the context of the **National Immunization Schedule (NIS)** in India, the Rotavirus vaccine (RVV) is administered in a 3-dose schedule at **6, 10, and 14 weeks** of age. The critical programmatic guideline is that the vaccination series **must be completed by 12 months of age**. If a child misses the scheduled doses, the vaccine should not be initiated or continued beyond the first birthday. The medical rationale for this age limit is based on the natural epidemiology of rotavirus infection and safety concerns. Most severe rotavirus-induced dehydration occurs in early infancy; by the time a child is older than one year, they have likely acquired natural immunity through subclinical exposure, reducing the benefit-to-risk ratio of the vaccine. **Analysis of Incorrect Options:** * **A & B (2 and 3 months):** These represent the ages when the first and second doses are typically administered (6 and 10 weeks). While the primary series starts here, the "completion" window extends much further. * **D (18 months):** This is incorrect as the risk of **intussusception** (a rare but serious side effect) was historically thought to increase if the vaccine was administered to older infants. Current NIS guidelines strictly cap the administration at 1 year. **High-Yield Clinical Pearls for NEET-PG:** * **Route & Dosage:** RVV is given **orally**. The dosage depends on the specific brand (e.g., **Rotavac** is 5 drops; **Rotasiil** is 2.5 ml). * **Type of Vaccine:** It is a **Live Attenuated** vaccine. * **Storage:** It is highly heat-sensitive and should be stored at **+2°C to +8°C**. * **VVM:** Rotavirus vaccine vials in India now come with Vaccine Vial Monitors (VVM) on the cap. * **Catch-up:** If a dose is missed, it can be given at any time before 12 months, maintaining a minimum 4-week interval between doses.

Q: What is true about the measles vaccine?

It can cause Toxic Shock Syndrome (TSS).. **Explanation:** **Correct Option (C): It can cause Toxic Shock Syndrome (TSS).** Toxic Shock Syndrome is a rare but severe complication associated with the measles vaccine, primarily due to **iatrogenic contamination**. It occurs when the reconstituted multi-dose vial is kept at room temperature for more than 4 hours, leading to the growth of *Staphylococcus aureus*. The bacteria produce exotoxins that cause rapid-onset high fever, vomiting, diarrhea, and circulatory collapse. **Analysis of Incorrect Options:** * **A. It is a killed vaccine:** Measles vaccine is a **Live Attenuated vaccine** (Edmonston-Zagreb strain). It is highly heat-sensitive and must be stored at +2°C to +8°C (though it can be frozen). * **B. In an epidemic, it is given at 9 months:** In outbreak situations or high-risk areas, the vaccine can be given as early as **6 months of age** (known as the "Measles Outbreak Dose"). Under the National Immunization Schedule (NIS), the first dose is routinely given at 9 completed months. * **D. Duration of protection:** The vaccine provides **long-lasting, likely lifelong immunity** in over 95% of recipients. It is not limited to 5-10 years. **High-Yield Clinical Pearls for NEET-PG:** * **Reconstitution:** Must be reconstituted only with the provided **Sterile Water** (Normal Saline is used for BCG). * **Discard Policy:** The vial must be discarded within **4 hours** of reconstitution or at the end of the session, whichever is earlier. * **Route:** Subcutaneous (0.5 ml) over the right upper arm. * **Vitamin A:** Always administered alongside the measles vaccine to reduce severity and prevent complications like keratomalacia.

Q: Vaccine can be stored at a subcentre for how long?

2 days. ### Explanation **Correct Answer: A. 2 days** In the Indian Universal Immunization Programme (UIP), the duration for which vaccines can be stored depends on the level of the **Cold Chain** system. At the **Subcentre level**, vaccines are typically stored in **Vaccine Carriers** (with conditioned ice packs) rather than active refrigeration units like ILRs (Ice-Lined Refrigerators). According to the National Immunization Guidelines, vaccines can be stored in a vaccine carrier at the subcentre for a maximum of **48 hours (2 days)**. This is because vaccine carriers are passive cooling devices and cannot maintain the required temperature (+2°C to +8°C) for extended periods. **Analysis of Incorrect Options:** * **B. 7 days:** This does not correspond to any standard storage duration in the cold chain hierarchy. * **C. 15 days:** This is the maximum storage duration for vaccines at the **PHC (Primary Health Centre)** level, where ILRs and Deep Freezers are available. * **D. 30 days:** This is the standard storage duration at the **District level** (District Vaccine Stores). Regional and State stores may store vaccines for up to 3 months. **High-Yield Clinical Pearls for NEET-PG:** * **Cold Chain Temperature:** Most vaccines under UIP are stored between **+2°C to +8°C**. * **Most Heat Sensitive Vaccine:** Oral Polio Vaccine (OPV). * **Most Freeze Sensitive Vaccine:** Hepatitis B (followed by Tetanus Toxoid). * **ILR Placement:** Vaccines are stored in the basket of the ILR; never on the floor of the unit. Freeze-sensitive vaccines are kept at the top, while heat-sensitive vaccines are kept at the bottom. * **Open Vial Policy:** Applies to multi-dose vials of DPT, TT, Hep B, OPV, and Hib. It does **not** apply to reconstituted vaccines like BCG, Measles/MR, and JE (must be discarded after 4 hours or at the end of the session).

Q: An 11-month-old child presents for vaccination. He has previously received Polio vaccine and BCG. What vaccines should be administered at this visit?

Measles, DPT, OPV, Hib, Hepatitis B. ### Explanation The core concept tested here is the **National Immunization Schedule (NIS)** of India and the management of a **"partially immunized"** child. **1. Why Option B is Correct:** The child is 11 months old and has only received BCG and Polio (likely OPV 0 at birth). According to the NIS, the primary series of **Pentavalent (DPT + Hep B + Hib)** and **OPV** (3 doses) should have been completed at 6, 10, and 14 weeks. Since the child missed these, they must be administered now as "catch-up" vaccination. Additionally, the first dose of **Measles (MR-1)** is scheduled at 9 completed months. Therefore, at 11 months, the child is eligible for all these antigens simultaneously. **2. Analysis of Incorrect Options:** * **Option A:** BCG is already given; repeating it is unnecessary. * **Option C & D:** These options omit **Measles**, which is the most critical vaccine to be administered between 9–12 months of age. Option D also misses **Hib**, which is now integrated into the Pentavalent vaccine in the NIS. **3. High-Yield Clinical Pearls for NEET-PG:** * **Pentavalent Vaccine:** Replaced individual DPT, Hep B, and Hib doses. It is given IM in the anterolateral aspect of the mid-thigh. * **Measles/MR Vaccine:** Administered Subcutaneously (SC) in the right upper arm. * **Catch-up Rule:** Under the NIS, DPT and Hep B can be given up to 7 years and 1 year of age, respectively. However, Pentavalent is generally given up to 1 year. * **Vitamin A:** Don't forget that the 1st dose of Vitamin A (1 lakh IU) is administered orally along with the 1st dose of Measles at 9 months. * **Open Vial Policy:** Applies to DPT, Hep B, OPV, and Pentavalent; it does **not** apply to Measles or BCG (must be discarded after 4 hours).

Q: Which of the following is NOT true for 'Live Vaccines'?

Two live vaccines cannot be given simultaneously.. **Explanation:** The correct answer is **A**. This statement is false because **two live vaccines can be administered simultaneously** at different injection sites (e.g., MMR and Varicella). If they are not given on the same day, a minimum interval of **4 weeks** is required to prevent the interferon produced by the first vaccine from interfering with the replication of the second. **Analysis of Options:** * **Option B (True):** Live vaccines are generally **contraindicated in immunocompromised states** (Leukemia, Lymphoma, HIV with CD4 <200, or high-dose steroids) because the attenuated organism can cause disseminated, life-threatening disease. * **Option C (True):** Live vaccines mimic natural infection. They **engage specific body tissues** (e.g., OPV replicates in the intestinal mucosa) to induce both humoral (IgG/IgA) and cell-mediated immunity. * **Option D (True):** Because the organism multiplies within the host, a **single dose** usually provides long-lasting immunity. Exceptions include OPV (requires multiple doses to overcome interference from other enteroviruses) and Rotavirus. **High-Yield Clinical Pearls for NEET-PG:** * **The "4-Week Rule":** If two live parenteral vaccines are not given together, wait 28 days. * **Pregnancy:** All live vaccines are contraindicated in pregnancy (exception: Yellow Fever if the risk of disease outweighs the risk of vaccination). * **Heat Sensitivity:** OPV is the most heat-sensitive vaccine; BCG is the most light-sensitive. * **Exceptions to Single Dose:** Oral Polio Vaccine (OPV) and Rotavirus are live vaccines that require multiple doses.

Q: An OPV vial shows a specific symbol on it. 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*** - The **Vaccine Vial Monitor (VVM)** symbol on OPV vials changes color based on cumulative heat exposure, with the inner square remaining lighter than the outer circle in stages 1-2, indicating the vaccine is still potent. - When the VVM shows the inner square **lighter than the outer circle** and the **expiry date has not passed**, the vaccine should be used as it maintains its efficacy. *The vaccine has reached its expiry date* - The VVM symbol indicates **heat exposure status**, not expiry date - the actual expiry date is printed separately on the vial label. - A VVM can show **stage 1-2 (usable)** even when the expiry date has passed, but expiry date takes precedence in decision-making. *The vaccine has not been stored properly* - Improper storage would cause the VVM to progress to **stage 3-4** where the inner square becomes **equal to or darker** than the outer circle. - The question implies the symbol shows **acceptable storage conditions** since it suggests continued use under certain circumstances. *The vaccine vial is empty* - The VVM symbol has **no relationship** to the vaccine volume or whether the vial contains vaccine. - An empty vial would be determined by **visual inspection** of the contents, not by interpreting the heat-sensitive VVM symbol.

Q: Which disease is prevented by giving a booster dose to a 5-6 year old child?

Diphtheria-Tetanus-Pertussis (DPT). **Explanation:** The correct answer is **Diphtheria-Tetanus-Pertussis (DPT)**. Under the National Immunization Schedule (NIS) in India, the **DPT 2nd Booster** is specifically administered at **5–6 years of age**. This dose is crucial because the immunity derived from the primary series (at 6, 10, and 14 weeks) and the 1st booster (at 16–24 months) begins to wane by school entry age. Providing this booster ensures robust protection against Diphtheria, Tetanus, and Pertussis during the early school years. **Analysis of Incorrect Options:** * **Measles (A):** Under the NIS, the first dose is given at 9 completed months and the second dose (as MR vaccine) at 16–24 months. There is no routine booster scheduled at 5–6 years. * **BCG (B):** This is administered at birth (or up to 1 year if missed). Repeat BCG or booster doses are not recommended by the WHO or the Government of India, regardless of Mantoux status. * **Diphtheria-Tetanus (DT) (C):** DT is used as a replacement for DPT only in children who have a contraindication to the Pertussis component (e.g., progressive neurological disorders). It is not the standard vaccine for the general population at this age. **High-Yield NEET-PG Pearls:** * **DPT vs. Td:** DPT is given up to 7 years of age. For children older than 7, the **Td (Tetanus and adult-dose Diphtheria)** vaccine is used because the full-strength Pertussis and Diphtheria components in DPT can cause severe local reactions in older children. * **School Entry Vaccine:** The 5–6 year DPT booster is often referred to as the "school entry" vaccine. * **Recent Change:** Note that the 10-year and 16-year doses, previously TT (Tetanus Toxoid), have now been replaced by **Td** to maintain diphtheria immunity in the population.

Question 1

Immunization with Rotavirus should be completed by what age?

Accepted Answer

12 months

Answer

2 months

Answer

3 months

Answer

18 months

Question 2

What is true about the measles vaccine?

Accepted Answer

It can cause Toxic Shock Syndrome (TSS).

Answer

It is a killed vaccine.

Answer

In an epidemic, it is given at 9 months of age.

Answer

The duration of protection is 5-10 years.

Question 3

Peripheral health workers return one day late after an immunization session. The primary health centre is locked. The vaccine carrier still contains a few unopened vials of DPT vaccine and sufficient ice. What should the workers do?

Accepted Answer

Retain the vaccine in the ice box.

Answer

Return the vaccine vials to the refrigerator in the morning of the next day.

Answer

Get the health centre opened the same evening and keep the vaccine vials in the refrigerator.

Answer

Discard the vaccine vials.

Question 4

Vaccine can be stored at a subcentre for how long?

Accepted Answer

2 days

Answer

7 days

Answer

15 days

Answer

30 days

Question 5

An 11-month-old child presents for vaccination. He has previously received Polio vaccine and BCG. What vaccines should be administered at this visit?

Accepted Answer

Measles, DPT, OPV, Hib, Hepatitis B

Answer

BCG, OPV, Hepatitis B

Answer

DPT, OPV, Hib, Hepatitis B

Answer

DPT, OPV, Hepatitis B

Question 6

Which of the following is NOT true for 'Live Vaccines'?

Accepted Answer

Two live vaccines cannot be given simultaneously.

Answer

Live vaccines should not be administered to a patient with Leukemia.

Answer

Live vaccines engage certain tissues of the body.

Answer

With few exceptions, immunization is generally achieved with a single dose of a live vaccine.

Question 7

An OPV vial shows a specific symbol on it. 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 8

DPT is contraindicated in which of the following conditions?

Accepted Answer

Progressive neurological illness

Answer

Family history of convulsions

Answer

Acute respiratory tract infection

Answer

Cerebral palsy

Question 9

Which vaccine is contraindicated in a child who is positive for Intestinal Rotavirus (IRV)?

Accepted Answer

Oral Polio Vaccine (OPV)

Answer

Measles, Mumps, and Rubella (MMR) vaccine

Answer

Rabies vaccine

Answer

Influenza vaccine

Question 10

Which disease is prevented by giving a booster dose to a 5-6 year old child?

Accepted Answer

Diphtheria-Tetanus-Pertussis (DPT)

Answer

Measles

Answer

BCG

Answer

Diphtheria-Tetanus (DT)

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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