Immunization and Vaccine-Preventable Diseases Practice Questions

Q: Which vaccine is administered as nasal drops?

Influenza. **Explanation:** The correct answer is **Influenza**. Specifically, the **Live Attenuated Influenza Vaccine (LAIV)** is administered via the intranasal route. This vaccine is designed to mimic the natural portal of entry for the virus, inducing local mucosal immunity (IgA) in the nasopharynx as well as systemic immunity. It is commonly used in pediatric populations and is preferred for its non-invasive delivery. **Analysis of Options:** * **Rubella:** This is a live attenuated vaccine (RA 27/3 strain) administered via the **Subcutaneous (SC)** route, usually as part of the MMR or MR combination. * **Poliomyelitis:** There are two types: the Oral Polio Vaccine (OPV/Sabin), which is administered **Orally**, and the Inactivated Polio Vaccine (IPV/Salk), which is administered **Intramuscularly (IM)** or intradermally (fIPV). * **Measles:** This is a live attenuated vaccine (Edmonston-Zagreb strain) administered via the **Subcutaneous (SC)** route. While aerosolized measles vaccines have been researched, they are not the standard of care. **High-Yield Clinical Pearls for NEET-PG:** * **LAIV vs. TIV:** The Live Attenuated Influenza Vaccine is intranasal, whereas the Trivalent Inactivated Vaccine (TIV) is administered intramuscularly. * **Contraindications for LAIV:** Because it is a live vaccine, it is contraindicated in pregnant women, immunocompromised individuals, and children with severe asthma. * **Other Nasal Vaccines:** Apart from Influenza, the **Live Attenuated Japanese Encephalitis (SA-14-14-2)** vaccine has been studied for nasal delivery, but Influenza remains the classic exam answer for this route. * **Storage:** Most live vaccines, including the nasal flu vaccine, require strict cold chain maintenance (2°C to 8°C).

Q: Dukoral vaccine is used for which of the following diseases?

Cholera. **Explanation:** **Dukoral** is an oral, killed whole-cell vaccine used for the prevention of **Cholera**. It consists of heat- and formalin-killed *Vibrio cholerae* O1 (both Inaba and Ogawa serotypes) combined with a recombinant non-toxic B-subunit of the cholera toxin (WC/rBS). The B-subunit provides additional cross-protection against Enterotoxigenic *Escherichia coli* (ETEC) by neutralizing the heat-labile toxin (LT). **Analysis of Options:** * **Typhoid (A):** Common vaccines include the injectable Vi polysaccharide (Typhim Vi) and the oral live-attenuated Ty21a (Vivotif). * **Yellow Fever (C):** This is prevented by the **17D strain** vaccine, which is a live-attenuated vaccine administered subcutaneously. * **Influenza (D):** Prevention involves annual shots of inactivated (TIV/QIV) or live-attenuated nasal spray (LAIV) vaccines. **High-Yield Clinical Pearls for NEET-PG:** * **Administration:** Dukoral is administered orally with a buffer (sodium bicarbonate) to protect the B-subunit from gastric acid. * **Dosage:** For adults and children >6 years, 2 doses are given 1–6 weeks apart. For children 2–6 years, 3 doses are required. * **Other Cholera Vaccines:** * **Shanchol & Euvichol:** Bivalent (O1 and O139) killed whole-cell vaccines. Unlike Dukoral, they do **not** contain the B-subunit and do not require a buffer. * **Herd Immunity:** Oral cholera vaccines (OCVs) are known to provide significant herd protection in endemic areas. * **Traveler’s Diarrhea:** Dukoral is often prescribed to travelers for short-term protection against ETEC-induced diarrhea.

Q: A wildlife officer presents for pre-exposure rabies vaccination. How many doses of HDCV (Human Diploid Cell Vaccine) are recommended for rabies pre-exposure prophylaxis?

3. ### Explanation **Correct Answer: C (3 doses)** **Medical Concept:** Pre-exposure prophylaxis (PrEP) for rabies is recommended for individuals at high risk of exposure, such as wildlife officers, veterinarians, and laboratory workers. According to the **WHO and National Guidelines (India)**, the standard intramuscular (IM) regimen for PrEP consists of **3 doses** of modern cell-culture vaccines (like HDCV or PCECV). The schedule is administered on **Days 0, 7, and 21 (or 28)**. The primary goal is to induce immunological memory and simplify post-exposure management by eliminating the need for Rabies Immunoglobulin (RIG). **Analysis of Options:** * **Option A (1 dose):** A single dose is insufficient to prime the immune system or create lasting memory cells. * **Option B (2 doses):** While some recent WHO updates discuss a 2-dose PrEP schedule (Days 0 and 7) for specific cost-effective public health strategies, the standard academic and clinical gold standard for exams remains the 3-dose regimen. * **Option D (4 doses):** This is the standard **Post-Exposure Prophylaxis (PEP)** schedule (Essen regimen: 0, 3, 7, 14) for immunocompetent individuals who have *not* been previously vaccinated. **High-Yield Clinical Pearls for NEET-PG:** * **Site of Injection:** Always the **Deltoid muscle** (adults) or anterolateral thigh (children). Never the gluteal region, as fat interferes with vaccine absorption. * **Re-exposure after PrEP:** If a previously vaccinated person (who completed the 3-dose PrEP) is bitten, they only need **2 booster doses** (Days 0 and 3). RIG is **not** required. * **Intradermal (ID) Route:** PrEP can also be given via the ID route (0.1 ml) on the same schedule (0, 7, 21/28) to save costs. * **HDCV:** It is considered the "Gold Standard" vaccine due to high immunogenicity and low adverse effects.

Q: Which of the following vaccines is NOT included in the National Immunization Programme?

Hepatitis B. **Explanation:** The question asks to identify the vaccine **not** included in the National Immunization Programme (NIP). However, it is important to note that in the current Indian context, **all four options are actually part of the Universal Immunization Programme (UIP).** If this question appears in a competitive exam like NEET-PG, it is likely a **recalled/older question** or contains a technicality regarding nomenclature. Historically, Hepatitis B was the last of these four to be integrated into the national schedule (phased in from 2002-2011). 1. **Hepatitis B (Correct Option for this specific MCQ):** While now a core component of the UIP (given at birth, 6, 10, and 14 weeks), it was traditionally the "odd one out" in older textbooks compared to the original Expanded Programme on Immunization (EPI) vaccines. 2. **Tetanus Toxoid (TT):** This has been replaced by **Td (Tetanus and adult Diphtheria)** in the current UIP schedule for pregnant women and children (10 & 16 years) to provide continued protection against Diphtheria. 3. **Oral Polio Vaccine (OPV):** A cornerstone of the UIP, given as a birth dose and a primary series (6, 10, 14 weeks) along with fractional IPV. 4. **Measles:** Now administered as the **MR (Measles-Rubella)** vaccine at 9-12 months and 16-24 months. **High-Yield Clinical Pearls for NEET-PG:** * **Mission Indradhanush:** Launched to achieve 90% full immunization coverage. * **Pentavalent Vaccine:** Combines DPT, Hep B, and Hib (Haemophilus influenzae type b). * **Rotavirus Vaccine:** Now rolled out nationwide in the UIP. * **PCV (Pneumococcal Conjugate Vaccine):** The most recent major addition to the national schedule. * **Open Vial Policy:** Applies to Multi-dose vials of OPV, DPT, Hep B, Td, and IPV (but **not** to reconstituted vaccines like Measles/BCG).

Q: Acute flaccid paralysis is reported in a child aged:

0-15 years. ### Explanation **1. Why 0-15 years is the Correct Answer:** Under the **Global Polio Eradication Initiative**, Acute Flaccid Paralysis (AFP) surveillance is the gold standard for detecting cases of poliomyelitis. The operational definition for AFP surveillance includes any child **under 15 years of age** who presents with a sudden onset of flaccid weakness or paralysis. This age group is targeted because children under 15 are biologically most susceptible to paralytic poliomyelitis. Additionally, any person of any age must be reported if a clinician strongly suspects polio. **2. Analysis of Incorrect Options:** * **A (0-3 years) & B (3-5 years):** While younger children are at the highest risk for contracting polio (often called "infantile paralysis"), limiting surveillance to these ages would result in missing a significant number of cases in older children, thereby failing to detect circulating poliovirus in the community. * **D (15-19 years):** While adolescents can technically contract polio, they are not the primary target for routine AFP surveillance protocols unless there is a high clinical suspicion. **3. NEET-PG High-Yield Clinical Pearls:** * **AFP Surveillance Criteria:** A sensitive surveillance system must detect at least **3 cases of non-polio AFP per 100,000 children** under 15 years of age annually (in India). * **Specimen Collection:** To confirm or rule out polio, **two "adequate" stool samples** must be collected 24–48 hours apart, within 14 days of the onset of paralysis. * **The "60-Day" Rule:** All AFP cases must be followed up at 60 days from the onset of paralysis to check for residual paralysis, which is a hallmark of paralytic polio. * **Differential Diagnosis for AFP:** The most common cause of non-polio AFP is **Guillain-Barré Syndrome (GBS)**.

Q: In which year was the Pulse Polio immunization program introduced?

1995. **Explanation:** The **Pulse Polio Immunization (PPI)** program was launched in India in **1995** (specifically on December 9, 1995) following the World Health Assembly resolution of 1988. The program aimed at 100% coverage under the Global Polio Eradication Initiative. **Why 1995 is correct:** The strategy involved administering two doses of Oral Polio Vaccine (OPV) to all children under five years of age, regardless of their previous immunization status, on "National Immunization Days" (NIDs). This "pulse" approach was designed to flood the community with the vaccine virus to displace the wild poliovirus. **Analysis of Incorrect Options:** * **1999 & 2000:** These years represent the intensification phase of the program. In 1999, "House-to-House" vaccination was introduced to reach missed children, but the program itself was already well-established. * **2001:** By this time, India had significantly reduced polio cases, but this date does not correlate with any major milestone in the program's inception. **High-Yield Clinical Pearls for NEET-PG:** * **Last Case of Polio in India:** Reported on January 13, 2011, in Howrah, West Bengal. * **WHO Certification:** India was declared "Polio Free" on **March 27, 2014**. * **Vaccine Shift:** India switched from Trivalent OPV (tOPV) to **Bivalent OPV (bOPV)** in April 2016. * **Current Strategy:** Inclusion of **Inactivated Poliovirus Vaccine (IPV)** in the routine immunization schedule to prevent Vaccine-Associated Paralytic Polio (VAPP).

Q: All of the following vaccinations are administered via the subcutaneous route, except:

Hepatitis B. **Explanation:** The route of administration for vaccines is determined by the vaccine's composition and the desired immune response. **Hepatitis B (Correct Answer):** This vaccine is administered via the **Intramuscular (IM)** route. In infants, it is given in the anterolateral aspect of the mid-thigh, while in adults, it is given in the deltoid muscle. It must never be given in the gluteal region due to the risk of injury to the sciatic nerve and lower immunogenicity (due to fatty tissue). Furthermore, Hepatitis B is an **adsorbed vaccine** (containing aluminum salts); if injected subcutaneously, it can cause local irritation, granulomas, or tissue necrosis. **Incorrect Options (Subcutaneous Vaccines):** * **Measles & MR (Measles-Rubella):** Under the Universal Immunization Programme (UIP), these live attenuated vaccines are strictly administered via the **Subcutaneous (SC)** route, usually in the right upper arm. * **Japanese Encephalitis (JE):** The live attenuated (SA-14-14-2) vaccine used in the national program is administered via the **Subcutaneous** route in the left upper arm. **High-Yield Clinical Pearls for NEET-PG:** * **Intradermal (ID) Vaccines:** BCG, Fractional IPV (fIPV), and Rabies (Post-exposure prophylaxis - Thai Red Cross regimen). * **Intramuscular (IM) Vaccines:** DPT, Pentavalent, Hepatitis B, TT/Td, and PCV. * **Oral Vaccines:** OPV and Rotavirus. * **Site Tip:** Most SC vaccines in the UIP are given in the upper arm, whereas most IM vaccines in infants are given in the **Anterolateral thigh** (Vastus lateralis).

Q: What adjuvant is used in the DPT vaccine?

Aluminium. **Explanation:** The correct answer is **Aluminium (Option A)**. In the DPT (Diphtheria, Pertussis, and Tetanus) vaccine, aluminium salts—specifically **Aluminium hydroxide or Aluminium phosphate**—are used as adjuvants. **Why Aluminium?** An adjuvant is a substance added to a vaccine to enhance the body's immune response to an antigen. Aluminium works through the **"Depot Effect"**: it sequesters the vaccine antigens at the injection site, allowing for a slow, sustained release. This prolonged exposure triggers a more robust activation of Antigen Presenting Cells (APCs) and a stronger antibody response, which is essential for inactivated vaccines like DPT. **Analysis of Incorrect Options:** * **B, C, and D (Magnesium, Manganese, Silica):** These elements are not used as adjuvants in human vaccines. While silica is sometimes used in experimental immunology research, it is not part of the standard DPT formulation. Magnesium and Manganese are essential minerals but lack the specific immunostimulatory properties required for vaccine stabilization. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Injection:** Because DPT contains an aluminium adjuvant, it must be administered via **Deep Intramuscular (IM)** injection. If injected subcutaneously, the aluminium can cause local irritation, sterile abscesses, or "vaccination granulomas." * **Storage:** Vaccines with aluminium adjuvants (like DPT, TT, HepB, and Pentavalent) are **freeze-sensitive**. Freezing causes the adjuvant to precipitate, destroying the vaccine's potency. * **Shake Test:** If a DPT vial is suspected of being frozen, the "Shake Test" is performed to check for flocculation (clumping) of the aluminium adjuvant. * **Adjuvant in other vaccines:** Aluminium is also the standard adjuvant for Hepatitis B and Tetanus Toxoid (TT) vaccines.

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.

Question 1

Which vaccine is administered as nasal drops?

Accepted Answer

Influenza

Answer

Rubella

Answer

Poliomyelitis

Answer

Measles

Question 2

Dukoral vaccine is used for which of the following diseases?

Accepted Answer

Cholera

Answer

Typhoid

Answer

Yellow fever

Answer

Influenza

Question 3

A wildlife officer presents for pre-exposure rabies vaccination. How many doses of HDCV (Human Diploid Cell Vaccine) are recommended for rabies pre-exposure prophylaxis?

Accepted Answer

3

Answer

1

Answer

2

Answer

4

Question 4

Which of the following vaccines is NOT included in the National Immunization Programme?

Accepted Answer

Hepatitis B

Answer

Tetanus Toxoid (TT)

Answer

Oral Polio Vaccine (OPV)

Answer

Measles

Question 5

Acute flaccid paralysis is reported in a child aged:

Accepted Answer

0-15 years

Answer

0-3 years

Answer

3-5 years

Answer

15-19 years

Question 6

In which year was the Pulse Polio immunization program introduced?

Accepted Answer

1995

Answer

2000

Answer

1999

Answer

2001

Question 7

All of the following vaccinations are administered via the subcutaneous route, except:

Accepted Answer

Hepatitis B

Answer

Japanese encephalitis

Answer

Measles

Answer

MR

Question 8

What adjuvant is used in the DPT vaccine?

Accepted Answer

Aluminium

Answer

Magnesium

Answer

Manganese

Answer

Silica

Question 9

Active and passive immunity should be given together in all of the following conditions except?

Accepted Answer

Measles

Answer

Tetanus

Answer

Rabies

Answer

Hepatitis B

Question 10

Immunization with Rotavirus should be completed by what age?

Accepted Answer

12 months

Answer

2 months

Answer

3 months

Answer

18 months

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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