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: After reconstitution, the vaccine must be stored in the dark at 2-8 degree C and used within what time frame?

6 hours. ### Explanation The correct answer is **6 hours**. This time frame is a critical component of the **Open Vial Policy** and cold chain management for specific reconstituted vaccines. #### 1. Why 6 hours is correct Most live-attenuated lyophilized (freeze-dried) vaccines, such as **BCG, Measles, MR, and Japanese Encephalitis (JE)**, lose their potency and are highly susceptible to bacterial contamination once reconstituted with a diluent. According to Universal Immunization Programme (UIP) guidelines, these vaccines must be kept at 2–8°C and **discarded after 6 hours** (or at the end of the immunization session, whichever comes first). This prevents the risk of **Toxic Shock Syndrome (TSS)**, which can occur if *Staphylococcus aureus* contaminates a multi-dose vial. #### 2. Why the other options are incorrect * **1, 2, or 3 hours:** These time frames are too short. While using the vaccine sooner is safer, the standardized public health protocol allows for a 6-hour window to minimize vaccine wastage while ensuring safety. Discarding at 1–3 hours would lead to unnecessary disposal of viable doses in high-volume clinics. #### 3. Clinical Pearls & High-Yield Facts for NEET-PG * **Open Vial Policy (OVP):** This policy applies to multi-dose vials of **DPT, TT, Hep B, OPV, and Hib**. These can be used for up to **28 days** if stored correctly. * **Exceptions to OVP:** Reconstituted vaccines (**BCG, Measles, JE**) are **EXEMPT** from the Open Vial Policy; they must be discarded within 6 hours. * **Photosensitivity:** The **BCG vaccine** is particularly sensitive to light, which is why it is supplied in dark-colored (amber) glass vials. * **Diluents:** Never switch diluents between different vaccines. For example, BCG uses Normal Saline, while Measles uses Sterile Water. Using the wrong diluent can cause severe adverse events or vaccine failure.

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: 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.

Q: What is the efficacy of the Measles vaccine after the second dose?

99%. ### Explanation The efficacy of the Measles vaccine is highly dependent on the number of doses administered and the age at which they are given. **1. Why 99% is the Correct Answer:** The Measles vaccine (Live Attenuated, Edmonston-Zagreb strain) is highly immunogenic. While a single dose administered at 9 months provides approximately **95%** protection, a small percentage of children fail to seroconvert (primary vaccine failure). The **second dose** is administered to catch those who did not respond to the first dose. After the completion of a two-dose schedule, the cumulative efficacy reaches **99%**, providing near-total protection against the virus. **2. Analysis of Incorrect Options:** * **90% (Option A):** This is lower than the standard efficacy of even a single dose. * **95% (Option B):** This is the efficacy typically associated with a **single dose** of the measles vaccine when given after 9 months of age. * **100% (Option D):** No vaccine is 100% effective due to biological variations in host immune responses and potential cold chain failures. **3. High-Yield Clinical Pearls for NEET-PG:** * **Schedule:** Under the National Immunization Schedule (NIS) in India, Measles (as MR vaccine) is given in 2 doses: 1st dose at **9-12 months** and 2nd dose at **16-24 months**. * **Type of Vaccine:** Live attenuated vaccine. * **Reconstitution:** Must be reconstituted with **Sterile Water** (Diluent). Once reconstituted, it must be used within **4 hours**; otherwise, it must be discarded due to the risk of *Staphylococcus aureus* contamination (Toxic Shock Syndrome). * **Cold Chain:** It is highly heat-sensitive and must be stored at **+2°C to +8°C** (though it can be frozen at the regional level). * **Contraindication:** Severe immunocompromised states and pregnancy. History of anaphylaxis to neomycin or gelatin.

Question 1

Post-exposure active immunity should be administered in all situations EXCEPT?

Accepted Answer

Measles

Answer

Tetanus

Answer

Rabies

Answer

Hepatitis B

Question 2

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 3

After reconstitution, the vaccine must be stored in the dark at 2-8 degree C and used within what time frame?

Accepted Answer

6 hours

Answer

1 hour

Answer

2 hours

Answer

3 hours

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

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 7

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 8

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 9

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)

Question 10

What is the efficacy of the Measles vaccine after the second dose?

Accepted Answer

99%

Answer

90%

Answer

95%

Answer

100%

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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