Immunization and Vaccine-Preventable Diseases Practice Questions

Q: Which of the following groups can receive a live attenuated vaccine?

Children under 8 years. **Explanation:** The core concept tested here is the **contraindication of live attenuated vaccines in immunocompromised states.** Live vaccines (e.g., BCG, OPV, Measles, MMR) contain weakened pathogens that can replicate. In a healthy individual, the immune system controls this replication to create immunity; however, in immunocompromised individuals, the vaccine strain can cause disseminated, life-threatening disease. **1. Why Option A is Correct:** Children under 8 years of age (who are otherwise healthy) have functional immune systems. In fact, the National Immunization Schedule (NIS) focuses heavily on this age group for live vaccines like BCG (at birth), OPV/Rotavirus (infancy), and Measles/MRR (9 months and 16-24 months). Age itself is not a contraindication unless the child has an underlying primary immunodeficiency. **2. Why Options B, C, and D are Incorrect:** * **B. HIV Patients:** Generally, live vaccines are contraindicated in symptomatic HIV or those with severe immunosuppression (CD4 count 2 weeks) suppress T-cell function, making live vaccines unsafe. * **D. Patients on Radiation:** Radiotherapy depletes rapidly dividing immune cells, leading to profound immunosuppression. **High-Yield NEET-PG Pearls:** * **Pregnancy** is a absolute contraindication for live vaccines (risk of teratogenicity). * **Exception in HIV:** In the WHO/Universal Immunization Program, **Measles** vaccine is given to HIV-infected children unless they are severely immunocompromised. * **Rule of Thumb:** Live vaccines should be delayed for at least **3 months** after stopping immunosuppressive therapy or chemotherapy.

Q: All of the following statements are true about the DPT vaccine EXCEPT:

It should be stored in a deep freezer.. **Explanation:** The DPT vaccine is a **freeze-sensitive** vaccine. The correct answer is **Option A** because storing DPT in a deep freezer is contraindicated; freezing causes the aluminum adjuvant to precipitate, leading to a loss of potency and an increased risk of sterile abscesses at the injection site. **Analysis of Options:** * **Option A (Correct):** DPT must be stored in the **ILR (Ice-Lined Refrigerator)** at **+2°C to +8°C**, never in a deep freezer. If freezing is suspected, the "Shake Test" is performed to check for damage. * **Option B:** Like most vaccines, DPT is heat and light-sensitive. Exposure to direct sunlight can lead to the degradation of the toxoid components. * **Option C:** According to standard logistics in the Universal Immunization Programme (UIP), the PHC level is expected to maintain a stock of vaccines sufficient for **3 months**, while the sub-center level maintains a stock for one month. * **Option D:** Under the **Open Vial Policy**, multi-dose vials of DPT can be used for up to 28 days if specific criteria are met. However, the option refers to the traditional practice where a vial used in an outreach session (outside the cold chain) should be discarded to prevent contamination and maintain the cold chain's integrity. **High-Yield Facts for NEET-PG:** * **Freeze-Sensitive Vaccines:** DPT, TT, Hepatitis B, Pentavalent, and IPV (Mnemonic: **D**on't **F**reeze **H**is **P**recious **I**njections). * **Heat-Sensitive Vaccines:** OPV (most sensitive), followed by Measles/BCG. * **Shake Test:** Used only for freeze-sensitive vaccines (DPT, TT, Hep B) to determine if they have been damaged by sub-zero temperatures. * **Storage Level:** At the District level, vaccines are stored in Walk-in Coolers (WIC); at PHC level, in ILRs.

Q: What is the highest risk level for failure of cold chain maintenance in the public health system?

Subcentre level. ### Explanation The **cold chain** is a system of transporting and storing vaccines at recommended temperatures from the point of manufacture to the point of use. The risk of cold chain failure increases as we move from the central level toward the periphery. **Why Subcentre level is the correct answer:** The Subcentre represents the **farthest point (periphery)** of the vaccine delivery system. At this level, vaccines are usually stored for a very short duration in **vaccine carriers** rather than active refrigeration units like ILRs (Ice-Lined Refrigerators). The risk is highest here due to: 1. **Lack of continuous power supply** and dedicated cold chain equipment. 2. **Frequent opening** of vaccine carriers during outreach sessions. 3. **Human error** in maintaining ice packs (e.g., not using conditioned ice packs). 4. **Ambient temperature exposure** during field-level immunization. **Analysis of Incorrect Options:** * **District Hospitals, CHCs, and PHCs:** These levels are equipped with **Ice-Lined Refrigerators (ILRs)** and **Deep Freezers**. They have dedicated cold chain technicians, power backups (generators), and standardized temperature monitoring logs, making them significantly more secure than the Subcentre. **High-Yield Clinical Pearls for NEET-PG:** * **Weakest Link:** While the Subcentre has the highest risk of failure, the **Village level** (during actual administration) is often cited as the "weakest link" in the chain. * **ILR Temperature:** Most vaccines under UIP are stored between **+2°C to +8°C**. * **Most Heat Sensitive Vaccine:** Oral Polio Vaccine (OPV). * **Most Heat Resistant Vaccine:** Tetanus Toxoid (TT) / Td. * **Cold Chain Equipment at PHC:** The PHC is the lowest level where vaccines are stored for up to one month in an ILR.

Q: A 9-month-old, unimmunized child can be given which of the following vaccinations in a single visit?

BCG, DPT-1, OPV-1, Measles. **Explanation:** The core concept tested here is the **National Immunization Schedule (NIS)** guidelines for "catch-up" immunization in an unimmunized child. **Why Option D is Correct:** According to the Universal Immunization Programme (UIP) in India, if a child presents for the first time at 9 months of age, they should receive all vaccines due at birth, 6, 10, and 14 weeks, plus the 9-month dose, provided there are no contraindications. * **BCG:** Can be given anytime up to 1 year of age. * **DPT & OPV:** The first doses (DPT-1, OPV-1) are initiated at this visit. * **Measles (MR-1):** The scheduled age for the first dose is 9 completed months. Administering these simultaneously at different injection sites is safe, effective, and prevents "missed opportunities" for immunization. **Analysis of Incorrect Options:** * **Option A & B:** These are incomplete. While these vaccines can be given, they ignore the fact that the child is also eligible for Measles (at 9 months) and BCG (up to 1 year). * **Option C:** This is also incomplete as it omits BCG. Since the child is under 1 year, BCG is still indicated to protect against childhood tuberculosis. **High-Yield NEET-PG Pearls:** 1. **BCG Limit:** BCG can be given up to **1 year** of age. Beyond 1 year, it is generally not recommended in the NIS. 2. **DPT Limit:** The DPT vaccine can be given up to **7 years** of age. 3. **OPV Limit:** OPV can be given up to **5 years** of age. 4. **Injection Sites:** When giving multiple injections, use different limbs (e.g., BCG in the left upper arm, DPT/Pentavalent in the anterolateral mid-thigh). 5. **Zero Dose:** OPV-0 is only given at birth; if the child is seen later, we start with OPV-1.

Q: Which of the following is known as the eighth day disease?

Tetanus neonatorum. **Explanation:** **Tetanus neonatorum** is known as the **"eighth day disease"** because symptoms typically manifest between the 3rd and 14th day after birth, with the majority of cases occurring around the **8th day**. It is caused by *Clostridium tetani* infection, usually due to unhygienic umbilical cord practices (the "3 Cs" violation: clean hands, clean surface, clean cord cut/tie). The incubation period is inversely related to the severity; the shorter the incubation, the higher the mortality. **Analysis of Options:** * **Puerperal tetanus:** This refers to tetanus occurring in the mother within 6 weeks of delivery or abortion. While related to the birthing process, it does not carry the "eighth day" moniker. * **Varicella (Chickenpox):** Known for its pleomorphic rash and "dewdrop on a rose petal" appearance. Its incubation period is typically 14–16 days. * **Measles:** Characterized by the prodromal triad (Cough, Coryza, Conjunctivitis) and Koplik's spots. It is not associated with the eighth-day timeline. **High-Yield Clinical Pearls for NEET-PG:** * **Elimination Status:** India achieved "Maternal and Neonatal Tetanus Elimination" (MNTE) in May 2015 (defined as <1 case per 1000 live births per district). * **Clinical Sign:** The earliest sign is often the **inability to suckle**, followed by muscular rigidity, spasms, and a characteristic "grimace" (risus sardonicus). * **Prevention:** Two doses of Tetanus Toxoid (TT/Td) during pregnancy and the promotion of institutional deliveries. * **Incubation Period Rule:** The "Rule of 8" is a useful mnemonic for the peak onset of neonatal tetanus.

Q: A PHC medical officer wants to give pulse polio immunization. Which finding in the Vaccine Vial Monitor (VVM) indicates that the vaccine should not be used?

Inner square matches the color of the outer circle. ### Explanation The **Vaccine Vial Monitor (VVM)** is a heat-sensitive label placed on vaccine vials (most critically Oral Polio Vaccine) to monitor cumulative heat exposure over time. It consists of a heat-sensitive inner square inside a reference outer circle. **Why Option C is Correct:** The VVM works on the principle that the inner square darkens as it is exposed to heat. The **"Discard Point"** is reached when the inner square matches the color of the outer circle or becomes darker than it. At this stage, the vaccine has likely lost its potency due to heat degradation and **must not be used**, even if the expiry date has not passed. **Analysis of Incorrect Options:** * **Option A & D:** These represent **Stage 1**. If the inner square is white or significantly lighter than the outer circle, the vaccine is potent and safe to use. * **Option B:** This represents **Stage 2**. As long as the inner square is still lighter than the outer circle, the vaccine can still be used. However, it indicates the vaccine should be used first (Earliest Expiry First Out principle). **High-Yield NEET-PG Pearls:** * **VVM Stages:** Stages 1 & 2 are usable; Stages 3 & 4 (square matches or is darker than the circle) are unusable. * **OPV Sensitivity:** OPV is the most heat-sensitive vaccine. VVM was first introduced for OPV in 1996. * **VVM Location:** For OPV, the VVM is on the **cap** (to be discarded after opening). For other vaccines, it is on the **label** (to remain even after opening, supporting the Multi-Dose Vial Policy). * **The "Shake Test":** Remember, the VVM is for heat sensitivity. The Shake Test is used for damage due to **freezing** (DPT, TT, Hepatitis B).

Question 1

For survey of immunization, what is the WHO age group selected?

Accepted Answer

12 - 23 months

Answer

0 - 6 months

Answer

6 - 12 months

Answer

2 - 5 years

Question 2

Which of the following groups can receive a live attenuated vaccine?

Accepted Answer

Children under 8 years

Answer

HIV patients

Answer

Patients on steroids

Answer

Patients on radiation

Question 3

All of the following statements are true about the DPT vaccine EXCEPT:

Accepted Answer

It should be stored in a deep freezer.

Answer

Exposure to direct sunlight when in use should be avoided.

Answer

Stock supplies are needed for three months at the Primary Health Centre level.

Answer

A partially used vial should not be put back into the cold chain after the session.

Question 4

What is the highest risk level for failure of cold chain maintenance in the public health system?

Accepted Answer

Subcentre level

Answer

District hospitals

Answer

Primary Health Centers (PHCs)

Answer

Community Health Centers (CHCs)

Question 5

A 9-month-old, unimmunized child can be given which of the following vaccinations in a single visit?

Accepted Answer

BCG, DPT-1, OPV-1, Measles

Answer

BCG

Answer

DPT-1, OPV-1

Answer

DPT-1, OPV-1, Measles

Question 6

Which of the following is known as the eighth day disease?

Accepted Answer

Tetanus neonatorum

Answer

Puerperal tetanus

Answer

Varicella

Answer

Measles

Question 7

Which of the following statements about pulse polio immunization is false?

Accepted Answer

AFP surveillance is done in all children less than 5 years of age.

Answer

Mop-up immunization is done in restricted geographical areas.

Answer

It is carried out in all children less than 5 years of age.

Answer

Mopping up is done in areas where wild polio virus is found.

Question 8

A PHC medical officer wants to give pulse polio immunization. Which finding in the Vaccine Vial Monitor (VVM) indicates that the vaccine should not be used?

Accepted Answer

Inner square matches the color of the outer circle

Answer

Inner square is white, outer circle is blue

Answer

Inner square is blue but lighter than outer circle

Answer

Inner square is lighter than outer circle

Question 9

Which of the following statements is TRUE regarding polio?

Accepted Answer

Intramuscular injections and increased muscular activity increase the risk of paralytic polio.

Answer

Most of the cases are symptomatic.

Answer

Spastic paralysis is seen.

Answer

Pulse polio immunization is indicated in all children less than 3 years of age.

Question 10

Which of the following is NOT true regarding the inactivated polio vaccine?

Accepted Answer

It provides immunity against paralytic and wild strains.

Answer

It produces circulatory antibodies.

Answer

It does not require stringent refrigeration.

Answer

It is not effective in an epidemic.

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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