Immunization and Vaccine-Preventable Diseases Practice Questions

Q: All of the following diseases are covered under the "MISSION INDRADHANUSH" program except?

Japanese encephalitis. **Explanation:** The correct answer is **Japanese Encephalitis (A)**. While Japanese Encephalitis (JE) is part of the Universal Immunization Programme (UIP), it is only included in **select endemic districts** rather than being a universal mandate across all regions under the standard Mission Indradhanush (MI) framework. **Understanding Mission Indradhanush:** Launched in December 2014, Mission Indradhanush aims to achieve full immunization coverage (90%) for children and pregnant women. It originally targeted **seven** vaccine-preventable diseases (VPDs), mirroring the "seven colors of the rainbow." * **Why Option A is correct:** Japanese Encephalitis is considered a "sub-national" vaccine. It is provided only in 297 high-burden districts in India. Since Mission Indradhanush focuses on universal coverage of the primary series, JE is the "exception" in a general national context. * **Why Options B, C, and D are incorrect:** Diphtheria, Pertussis (Whooping Cough), and Hepatitis B are part of the core **Pentavalent vaccine**. These are administered universally across all districts in India and were part of the original seven diseases targeted by the mission. **High-Yield NEET-PG Pearls:** 1. **Original 7 Diseases:** Diphtheria, Pertussis, Tetanus, Polio, Tuberculosis, Measles, and Hepatitis B. 2. **Recent Additions:** The program now covers 12 VPDs including Measles-Rubella (MR), Rotavirus, Pneumococcal Conjugate Vaccine (PCV), and Haemophilus influenzae type B (HiB). 3. **Intensified Mission Indradhanush (IMI):** Focuses on "left-outs" and "drop-outs" in low-coverage areas. IMI 5.0 (the latest phase) specifically aims to eliminate Measles and Rubella by 2023. 4. **JE Vaccine Strain:** The live attenuated **SA-14-14-2** strain is used in India.

Q: Which of the following vaccines requires a reverse cold chain?

Polio. **Explanation:** **1. Why Polio is the Correct Answer:** The **Reverse Cold Chain** is a system used to transport samples (usually stool) from a patient suspected of having a vaccine-preventable disease back to a laboratory for testing. In the context of Polio, it is a critical component of **Acute Flaccid Paralysis (AFP) surveillance**. To confirm a case of Polio, stool samples must be kept at a temperature between **2°C and 8°C** during transport to the laboratory to ensure the virus remains viable for culture. Without this reverse cold chain, the heat-sensitive virus would degrade, leading to a false-negative result. **2. Why the Other Options are Incorrect:** * **Measles, Rubella, and Pertussis:** These vaccines are part of the standard **Cold Chain** (transporting vaccines from the manufacturer to the patient to maintain potency). While these diseases are monitored, their surveillance protocols do not routinely rely on the transport of temperature-sensitive stool samples in the same manner as the Polio eradication program. **3. High-Yield Clinical Pearls for NEET-PG:** * **Cold Chain Temperature:** Most vaccines in the Universal Immunization Programme (UIP) are stored at **+2°C to +8°C** at the PHC level. * **Most Heat Sensitive Vaccine:** Oral Polio Vaccine (OPV). It is stored at **-20°C** at the district level and above. * **Most Heat Resistant Vaccine:** Tetanus Toxoid (TT) / Td. * **AFP Surveillance Criteria:** Requires two stool samples collected **24–48 hours apart**, within **14 days** of the onset of paralysis. * **Vaccine Vial Monitor (VVM):** A marker of heat exposure found on the label of OPV vials; if the inner square matches or is darker than the outer circle, the vaccine must be discarded.

Q: All of the following are true regarding tetanus, EXCEPT:

It is transmitted from person to person. **Explanation:** **1. Why Option A is the Correct Answer (The "Except" statement):** Tetanus is a non-communicable disease. It is caused by the neurotoxin produced by *Clostridium tetani*. Unlike many other vaccine-preventable diseases, **tetanus is not transmitted from person to person.** Infection occurs only through environmental exposure, typically via contamination of wounds (burns, injuries, or umbilical stumps) with tetanus spores. **2. Analysis of Other Options:** * **Option B (Herd immunity is not of much value):** This is **True**. Herd immunity relies on reducing the chain of human-to-human transmission. Since tetanus is acquired from the environment (soil) and not from other people, vaccinating 90% of the population does not protect the remaining 10%. Individual protection is only achieved through active immunization. * **Option C (Main reservoir is soil and intestine):** This is **True**. *C. tetani* is an obligate anaerobe. Its spores are ubiquitous in soil and the intestinal tracts of herbivorous animals and humans, where they exist in a commensal state. * **Option D (Incubation period is 6-10 days):** This is **True**. While the range can be 3 to 21 days, the average incubation period is approximately **6–10 days**. Generally, a shorter incubation period is associated with a poorer prognosis. **Clinical Pearls for NEET-PG:** * **Neonatal Tetanus:** Defined as tetanus occurring within 3–28 days of birth. It is a major target for "Elimination" (defined as <1 case per 1000 live births in every district). * **Type of Immunity:** Tetanus toxoid provides **active immunity**, while Tetanus Immunoglobulin (TIG) provides **passive immunity**. * **Natural Infection:** Surviving a clinical case of tetanus does **not** confer natural immunity; vaccination is still required. * **Drug of Choice:** Metronidazole is preferred over Penicillin G to treat the infection.

Q: Cholera vaccination is indicated:

In endemic areas. **Explanation:** The primary indication for cholera vaccination, according to WHO and the National Health Profile, is for individuals living in **endemic areas** (hotspots) where the risk of transmission is high. Modern Oral Cholera Vaccines (OCVs), such as Shanchol and Euvichol, are used as a pre-emptive tool to reduce the disease burden in these regions alongside improvements in water, sanitation, and hygiene (WASH). **Analysis of Options:** * **A. To control epidemics:** While OCVs are used in humanitarian crises to *prevent* outbreaks, they are generally **not** the primary tool for controlling an ongoing epidemic. In an active outbreak, the incubation period is so short (2 hours to 5 days) that the vaccine (requiring two doses 14 days apart) cannot provide immunity fast enough to halt the spread. * **B. For travelers:** While some countries recommend it, it is not a routine indication. The risk to most travelers is very low if they follow food and water precautions. It is only considered for high-risk humanitarian workers. * **D. In neonates:** Cholera vaccines are not indicated for neonates. Most OCVs are licensed for use in children **above 1 year of age** (Dukoral) or **above 2 years** (Shanchol). **High-Yield Facts for NEET-PG:** * **Vaccine Type:** Modern OCVs are **killed whole-cell vaccines**. * **Schedule:** 2 doses, given 14 days apart. * **Duration of Protection:** Provides ~65% protection for up to 3–5 years. * **Herd Immunity:** OCVs are unique because they provide significant indirect (herd) protection even with moderate coverage. * **Injectable Vaccine:** The old parenteral (injectable) killed vaccine is **obsolete** due to low efficacy and short duration of protection.

Q: All of the following vaccines are live vaccines except?

DPT. **Explanation:** The core concept tested here is the classification of vaccines based on their preparation method. Vaccines are broadly categorized into Live Attenuated, Killed (Inactivated), Toxoids, and Subunit/Recombinant types. **Why DPT is the correct answer:** DPT is a **combination vaccine** that does not contain any live organisms. It consists of: * **Diphtheria:** Toxoid (inactivated toxin) * **Pertussis:** Killed whole-cell bacteria (wP) or acellular components (aP) * **Tetanus:** Toxoid Since none of these components are live, DPT is the "except" in this list. **Analysis of incorrect options:** * **BCG (Bacillus Calmette–Guérin):** A live attenuated bacterial vaccine derived from *Mycobacterium bovis*. * **OPV (Oral Polio Vaccine/Sabin):** A live attenuated viral vaccine. (Note: The injectable IPV/Salk is a killed vaccine). * **Measles:** A live attenuated viral vaccine (usually administered as MMR or MR). **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for Live Vaccines:** "**B**oy **L**ove **CRIME** **V**ery **T**erribly" (**B**CG, **L**ive Typhoid/Ty21a, **C**holera, **R**otavirus, **I**nfluenza (Intranasal), **M**MR/Measles, **E**ndemic Typhus, **V**aricella, **Y**ellow Fever, **T**ularemia). * **Contraindication:** Live vaccines are generally contraindicated in pregnancy and immunocompromised individuals (HIV with CD4 <200). * **Storage:** Most live vaccines are heat-sensitive and must be stored in the "freezer compartment" or at +2°C to +8°C, whereas DPT is "freeze-sensitive" and must never be frozen.

Q: Which of the following is true about the Salk vaccine except?

OPV cannot be given as a booster dose.. **Explanation:** The question asks for the **incorrect** statement regarding the Salk vaccine (Inactivated Poliovirus Vaccine - IPV). **1. Why Option A is the Correct Answer (The False Statement):** Contrary to the option, **OPV can be given as a booster dose** even if the primary series was completed with IPV (Salk). In fact, the "Sequential Schedule" (IPV followed by OPV) is used in many programs to combine the safety of IPV with the superior mucosal immunity of OPV. Therefore, saying OPV *cannot* be given as a booster is medically incorrect. **2. Analysis of Incorrect Options (True Statements about Salk):** * **Option B:** True. Injections (including Salk) during a polio epidemic can lead to **"Provocative Poliomyelitis,"** where local trauma facilitates the virus reaching the CNS, leading to paralysis. * **Option C:** True. IPV is administered parenterally; it induces high levels of **humoral (IgG) antibodies** but fails to induce significant **local/mucosal immunity (Secretory IgA)** in the gut. * **Option D:** True. Because IPV lacks mucosal immunity, it **does not prevent the multiplication of wild poliovirus** in the intestinal tract. An IPV-vaccinated person is protected from paralysis but can still shed the virus in feces and spread it to others. **High-Yield Clinical Pearls for NEET-PG:** * **Salk (IPV):** Killed vaccine, contains 3 types (Mahoney, MEF-1, Saukett), given IM/SC, prevents paralysis but not transmission. * **Sabin (OPV):** Live attenuated, given orally, induces both systemic (IgG) and local (IgA) immunity, provides "Herd Immunity" via contact vaccination. * **VAPP vs. VDPV:** Vaccine-Associated Paralytic Polio (VAPP) is a risk with OPV, but **never** with IPV. * **Current Strategy:** India currently uses a combination of bOPV (Type 1 & 3) and fractional doses of IPV (fIPV) at 6, 14 weeks, and 9 months.

Question 1

All of the following diseases are covered under the "MISSION INDRADHANUSH" program except?

Accepted Answer

Japanese encephalitis

Answer

Hepatitis B

Answer

Whooping cough

Answer

Diphtheria

Question 2

Which of the following vaccines requires a reverse cold chain?

Accepted Answer

Polio

Answer

Measles

Answer

Rubella

Answer

Pertussis

Question 3

All of the following are true regarding tetanus, EXCEPT:

Accepted Answer

It is transmitted from person to person

Answer

Herd immunity is not of much value

Answer

The main reservoir is soil and intestine of animals and humans

Answer

Incubation period is 6-10 days

Question 4

Cholera vaccination is indicated:

Accepted Answer

In endemic areas

Answer

To control epidemics

Answer

For travelers

Answer

In neonates

Question 5

Which of the following statements regarding the Vi polysaccharide vaccine is true?

Accepted Answer

It can be administered concurrently with yellow fever and hepatitis A vaccines.

Answer

It has numerous serious systemic adverse reactions.

Answer

It has numerous serious local side effects.

Answer

It has many contraindications.

Question 6

All of the following vaccines are live vaccines except?

Accepted Answer

DPT

Answer

BCG

Answer

OPV

Answer

Measles

Question 7

Which of the following statements about vaccines is false?

Accepted Answer

Neomycin is a preservative in BCG vaccine.

Answer

Thiomersal is a preservative in DPT vaccine.

Answer

Kanamycin is a preservative in measles vaccine.

Answer

Magnesium chloride is used as a stabilizer in OPV.

Question 8

What is the best preventive measure against tetanus neonatorum?

Accepted Answer

Active immunization of the mother

Answer

Passive immunization of the child

Answer

Active immunization of the child

Answer

Passive immunization of the mother

Question 9

Which of the following is true about the Salk vaccine except?

Accepted Answer

OPV cannot be given as a booster dose.

Answer

Injections during an epidemic can cause paralysis.

Answer

Induces circulating antibody but no local immunity.

Answer

Does not prevent multiplication of wild virus in the gut.

Question 10

Which of the following vaccines can be administered to an HIV-positive child?

Accepted Answer

Diphtheria, Tetanus, and Pertussis (DTwP)

Answer

Bacillus Calmette-Guérin (BCG)

Answer

Measles

Answer

Oral Polio Vaccine (OPV)

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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