Immunization and Vaccine-Preventable Diseases Practice Questions

Q: Which of the following statements is true about BCG vaccination?

WHO recommends Danish 1331 strain for vaccine production. ### Explanation **Correct Option: D (WHO recommends Danish 1331 strain)** The BCG (Bacillus Calmette-Guérin) vaccine is a live attenuated vaccine derived from *Mycobacterium bovis*. To ensure global uniformity in potency and efficacy, the WHO recommends the **Danish 1331 strain** for vaccine production. This strain is known for providing a consistent immunological response and is the most widely used strain globally. **Analysis of Incorrect Options:** * **Option A:** **Normal Saline (0.9% NaCl)** is the recommended diluent for BCG. Distilled water is never used because it is hypotonic and can cause irritation or damage to the live bacilli, leading to decreased vaccine potency. * **Option B:** The injection site should be cleaned with **plain water** or left uncleaned if not visibly soiled. Using **spirit or alcohol** is strictly contraindicated because it kills the live attenuated bacteria in the vaccine, rendering it ineffective. * **Option C:** Post-vaccination tuberculin sensitivity (Mantoux conversion) does not happen instantly. It typically takes **8 to 12 weeks** for the Mantoux test to become positive, reflecting the development of cell-mediated immunity. **High-Yield NEET-PG Pearls:** * **Dose:** 0.05 ml for neonates (under 1 month) and 0.1 ml for infants above 1 month. * **Route:** Strictly **Intradermal** (left upper arm) using a tuberculin/Omega syringe. * **Storage:** Highly heat and light sensitive; must be stored at **+2°C to +8°C** and used within 3–4 hours of reconstitution. * **The "BCG Scar":** A papule forms at 2–3 weeks, followed by a crust/ulcer at 5 weeks, which heals to leave a permanent tiny round scar by 6–12 weeks. * **Protective Effect:** Primarily protects against severe forms of childhood TB (Miliary TB and TB Meningitis), but has variable efficacy against adult pulmonary TB.

Q: Which of the following vaccines is NOT included in Mission Indradhanush?

Meningococcal vaccine. **Explanation:** **Mission Indradhanush (MI)** was launched by the Ministry of Health and Family Welfare in December 2014 to strengthen the Universal Immunization Programme (UIP) and achieve full immunization coverage for all children and pregnant women. **1. Why Meningococcal Vaccine is the Correct Answer:** The Meningococcal vaccine is **not** part of the National Immunization Schedule or Mission Indradhanush in India. It is primarily recommended for specific high-risk groups, travelers (e.g., Hajj pilgrims), or during documented outbreaks, but it is not administered as a routine childhood vaccine under the government’s flagship program. **2. Analysis of Incorrect Options:** Mission Indradhanush originally targeted **seven** vaccine-preventable diseases (hence the name "Indradhanush" or Rainbow): **Diphtheria, Pertussis, Tetanus, Polio, Measles, Childhood Tuberculosis, and Hepatitis B.** * **Options A & B (Diphtheria and Pertussis):** These are core components of the DPT/Pentavalent vaccine included since the inception of MI. * **C (Hepatitis B):** This is a key component of the Pentavalent vaccine administered at 6, 10, and 14 weeks, and is a primary target of MI. **3. High-Yield Clinical Pearls for NEET-PG:** * **Evolution of MI:** While it started with 7 vaccines, the program now covers protection against **12 diseases** nationally (including Rubella, Rotavirus, *Haemophilus influenzae* type B, and Polio) and **Japanese Encephalitis** (in endemic districts) and **Pneumococcal Conjugate Vaccine (PCV)**. * **Intensified Mission Indradhanush (IMI):** Launched to reach "left-outs" and "drop-outs" in low-coverage districts. The latest version is **IMI 5.0**, which focuses on improving Measles-Rubella (MR) elimination. * **Pentavalent Vaccine:** Protects against Diphtheria, Pertussis, Tetanus, Hepatitis B, and Hib. It replaced the DPT and Hep B standalone doses in the routine schedule.

Q: What is Sanchol?

Cholera Vaccine. **Explanation:** **Shanchol** (often spelled Sanchol) is a bivalent, killed whole-cell **Oral Cholera Vaccine (OCV)**. It contains inactivated *Vibrio cholerae* O1 (Inaba and Ogawa serotypes) and O139. Unlike the earlier Dukoral vaccine, Shanchol does not contain the B-subunit of the cholera toxin, making it more heat-stable and cost-effective for mass immunization campaigns in endemic regions. **Analysis of Options:** * **Option B (Correct):** Shanchol is one of the two WHO-prequalified oral cholera vaccines (the other being Euvichol). It is administered in two doses, 14 days apart, and provides protection for up to 3–5 years. * **Option A (Incorrect):** Hormonal contraceptives include OCPs (Mala-N, Mala-D) or injectables (Antara/DMPA). Shanchol has no hormonal properties. * **Option C (Incorrect):** Nutritional supplements in public health usually refer to Iron-Folic Acid (IFA) or Vitamin A prophylaxis. * **Option D (Incorrect):** Pesticides used in community medicine include DDT, Malathion, or Temefos (Abate) for vector control. **High-Yield Clinical Pearls for NEET-PG:** * **Administration:** Shanchol is given **orally**. It does not require a buffer (unlike Dukoral), making it easier to administer in the field. * **Age Group:** It is licensed for use in individuals **≥1 year of age**. * **Herd Immunity:** It is highly effective in controlling outbreaks and is a key component of the "Ending Cholera: A Global Roadmap to 2030." * **Storage:** It should be stored at **2°C to 8°C**, but it is known for its relative stability at higher temperatures compared to other vaccines.

Q: Which of the following vaccines is NOT included in the Expanded Programme on Immunization (EPI) by WHO?

Chickenpox. **Explanation:** The **Expanded Programme on Immunization (EPI)** was launched by the WHO in 1974 to reduce morbidity and mortality from vaccine-preventable diseases. The original EPI focused on six "killer diseases": Tuberculosis, Diphtheria, Pertussis, Tetanus, Polio, and Measles. **Why Chickenpox is the Correct Answer:** Chickenpox (Varicella) is **not** part of the standard WHO EPI or India’s Universal Immunization Programme (UIP). While the vaccine is available in the private sector, it is not included in the global public health mandate for routine immunization due to its relatively lower mortality rate compared to the original EPI diseases and cost-effectiveness considerations in developing nations. **Analysis of Incorrect Options:** * **A. Tuberculosis:** Included since the inception of EPI via the **BCG vaccine**, administered at birth. * **B. Pertussis:** Included as part of the **DPT (Triple Vaccine)** or Pentavalent vaccine, targeting *Bordetella pertussis*. * **D. Measles:** A core component of EPI since 1974. In India, it is currently administered as the **MR (Measles-Rubella)** vaccine. **High-Yield Facts for NEET-PG:** * **EPI in India:** Launched in 1978; renamed the **Universal Immunization Programme (UIP)** in 1985. * **Latest Additions to UIP:** Rotavirus vaccine, Pneumococcal Conjugate Vaccine (PCV), and Rubella. * **Mission Indradhanush:** Launched in 2014 to achieve 90% full immunization coverage. * **The "Six Killer Diseases":** Remember the mnemonic **"TDP-MPT"** (Tuberculosis, Diphtheria, Pertussis, Measles, Polio, Tetanus).

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: 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: 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: Which of the following is not a type of VDPV?

mVDPV. **Explanation:** The correct answer is **A (mVDPV)**. Vaccine-Derived Polioviruses (VDPVs) are rare strains of poliovirus that have genetically mutated from the attenuated virus contained in the Oral Polio Vaccine (OPV). According to the World Health Organization (WHO), VDPVs are classified into three specific categories based on their origin and transmission; **"mVDPV" is not a recognized category.** **Analysis of Options:** * **cVDPV (Circulating VDPV):** These are the most common and clinically significant. They occur in communities with low vaccination coverage where the attenuated vaccine virus circulates for a prolonged period (usually >12 months), regaining neurovirulence and causing outbreaks. * **iVDPV (Immunodeficiency-associated VDPV):** These are isolated from individuals with rare primary immunodeficiencies (e.g., B-cell deficiency). These patients cannot clear the intestinal infection and may excrete the mutated virus for years. * **aVDPV (Ambiguous VDPV):** These are "catch-all" isolates that do not fit the other two categories. They include isolates from healthy people in communities with no known circulation or isolates from sewage where the source is unknown. **High-Yield NEET-PG Pearls:** * **Genetic Divergence:** A poliovirus is classified as a VDPV if it is **>1% divergent** from the parent OPV strain for Type 1 and 3, and **>0.6%** for Type 2. * **Type 2 Predominance:** Historically, Type 2 (OPV2) was responsible for >90% of cVDPV cases, leading to the global "switch" from trivalent to bivalent OPV. * **Public Health Importance:** While OPV is essential for stopping wild polio, the risk of VDPVs is the primary reason the world must eventually transition entirely to Inactivated Polio Vaccine (IPV).

Question 1

Which of the following statements about Pulse Polio immunization is false?

Accepted Answer

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

Answer

Mop-up immunization is conducted 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 poliovirus is found.

Question 2

Which of the following statements is true about BCG vaccination?

Accepted Answer

WHO recommends Danish 1331 strain for vaccine production

Answer

Distilled water is used as diluent for BCG vaccine

Answer

The site for injection should be cleaned thoroughly with spirit

Answer

Mantoux test becomes positive after 48 hours of vaccination

Question 3

Which of the following vaccines is NOT included in Mission Indradhanush?

Accepted Answer

Meningococcal vaccine

Answer

Diphtheria vaccine

Answer

Pertussis vaccine

Answer

Hepatitis B Vaccine

Question 4

What is Sanchol?

Accepted Answer

Cholera Vaccine

Answer

Hormonal contraceptive

Answer

Nutritional supplement

Answer

Pesticide

Question 5

Which of the following vaccines is NOT included in the Expanded Programme on Immunization (EPI) by WHO?

Accepted Answer

Chickenpox

Answer

Tuberculosis

Answer

Pertussis

Answer

Measles

Question 6

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 7

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 8

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 9

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

Accepted Answer

Tetanus neonatorum

Answer

Puerperal tetanus

Answer

Varicella

Answer

Measles

Question 10

Which of the following is not a type of VDPV?

Accepted Answer

mVDPV

Answer

aVDPV

Answer

iVDPV

Answer

cVDPV

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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