Vaccine and Vaccination Practice Questions

Q: For which of the following diseases are live vaccines used?

All of the above. **Explanation:** The correct answer is **D (All of the above)** because Measles, Cholera, and Smallpox all have versions that utilize live-attenuated microorganisms to induce immunity. 1. **Measles (Option A):** The measles vaccine is a classic example of a **live-attenuated viral vaccine**. It is typically administered as part of the MMR (Measles, Mumps, Rubella) or MR vaccine. It induces both humoral and cell-mediated immunity, mimicking a natural infection without causing the disease. 2. **Cholera (Option B):** While parenteral killed vaccines were used historically, the modern **Oral Cholera Vaccines (OCV)** include live-attenuated strains (e.g., **Vaxchora** using the *Vibrio cholerae* CVD 103-HgR strain). Note: Killed oral vaccines like Shanchol are also common, but the existence of a live version makes this option correct in a multiple-choice context. 3. **Smallpox (Option C):** The smallpox vaccine (Variola vaccine) uses the **live Vaccinia virus**. It is the most successful vaccine in history, leading to the global eradication of smallpox in 1980. **Clinical Pearls for NEET-PG:** * **Mnemonic for Live Vaccines:** "**B**oy **R**omeo **G**ive **M**y **L**ove **S**picy **V**ictory **T**onight" (**B**CG, **R**otavirus, **G**umbaro/not for humans, **M**MR, **L**ive Typhoid/Ty21a, **S**mallpox, **V**aricella/VZV, **T**yellow fever). * **Contraindications:** Live vaccines are generally contraindicated in **pregnancy** and **immunocompromised** individuals (HIV with low CD4 counts, chemotherapy, etc.) due to the risk of uncontrolled viral replication. * **Storage:** Most live vaccines are heat-sensitive and must be stored in the **Deep Freezer** (e.g., OPV, Measles) at the district level to maintain potency.

Q: Which of the following is not a live vaccine?

Tetanus. ### Explanation The correct answer is **D. Tetanus**. **1. Why Tetanus is the correct answer:** Vaccines are broadly classified into live-attenuated, killed (inactivated), toxoids, and subunit vaccines. **Tetanus** is a **toxoid vaccine**. It is prepared by treating the exotoxin produced by *Clostridium tetani* with formaldehyde, which renders it non-toxic while preserving its immunogenicity. It does not contain live organisms. **2. Analysis of Incorrect Options:** * **A. BCG (Bacillus Calmette-Guérin):** This is a **live-attenuated** bacterial vaccine derived from *Mycobacterium bovis*. It is the only live bacterial vaccine routinely used in the National Immunization Schedule. * **B. OPV (Oral Polio Vaccine/Sabin):** This is a **live-attenuated** viral vaccine. It induces both systemic (IgG) and local mucosal (IgA) immunity. (Note: IPV/Salk is the killed version). * **C. Measles:** This is a **live-attenuated** viral vaccine (Edmonston-Zagreb strain). It is typically administered at 9 months of age in India. **3. NEET-PG High-Yield Clinical Pearls:** * **Mnemonic for Live Vaccines:** "**B**oy **R**eally **I**s **V**ery **S**mart **Y**et **M**akes **M**any **L**ittle **T**yping **P**errors" (**B**CG, **R**otavirus, **I**ntranasal Influenza, **V**aricella, **S**abin/OPV, **Y**ellow Fever, **M**easles, **M**umps, **L**ive Typhoid/Ty21a, **P**lague). * **Contraindication:** Live vaccines are generally contraindicated in **pregnancy** and **immunocompromised** states (except HIV patients before the symptomatic stage, where BCG/Measles may be given based on CD4 counts). * **Storage:** Most live vaccines are heat-sensitive and must be stored in the **ILR (Ice-Lined Refrigerator)** at +2°C to +8°C; however, OPV is the most heat-sensitive and is stored at -20°C for long-term stability.

Q: What type of vaccine is currently used against hepatitis B infection?

Recombinant. **Explanation:** The Hepatitis B vaccine is a **Recombinant Subunit Vaccine**. It is produced using genetic engineering technology where the gene coding for the **Hepatitis B surface antigen (HBsAg)** is inserted into common baker’s yeast (*Saccharomyces cerevisiae*). The yeast cells then express and produce large quantities of HBsAg, which are harvested, purified, and used as the immunizing agent. This induces the production of protective **Anti-HBs antibodies**. **Analysis of Options:** * **A. Killed pooled serum:** Historically, the first-generation HBV vaccine (Heptavax) was derived from the plasma of chronic carriers. However, this was discontinued in the 1980s due to risks of contamination with live blood-borne pathogens (like HIV). * **B. Live attenuated:** There is no live-attenuated vaccine for Hepatitis B. Because HBV is a DNA virus associated with chronic carriage and hepatocellular carcinoma, using a live version poses significant safety risks. * **C. Recombinant (Correct):** This is the current "second-generation" vaccine. It is safe, contains no viral DNA, and cannot cause infection. * **D. Synthetic vaccine:** While research into synthetic peptide vaccines exists, they are not currently used in clinical practice for HBV. **Clinical Pearls for NEET-PG:** * **Schedule:** Given at 0, 1, and 6 months. * **Site:** Intramuscular (IM) injection in the **Deltoid** (adults) or **Anterolateral thigh** (infants). It should *never* be given in the gluteal region as the fat reduces vaccine efficacy. * **Non-responders:** Individuals who fail to develop an adequate antibody titer (>10 mIU/mL) after a complete series. * **Universal Immunization Program (UIP):** In India, the birth dose is crucial to prevent vertical transmission.

Q: Which of the following is NOT a live attenuated vaccine?

Influenza vaccine. **Explanation:** The correct answer is **D. Influenza vaccine**. In the context of standard medical examinations like NEET-PG, the "Influenza vaccine" typically refers to the **Inactivated Influenza Vaccine (IIV)**, which is administered intramuscularly. While a Live Attenuated Influenza Vaccine (LAIV) exists as a nasal spray, the injectable form used in routine practice is a killed/subunit vaccine. **Why Option D is correct:** Live attenuated vaccines contain pathogens that are weakened but still capable of replicating within the host to induce an immune response. The standard injectable Influenza vaccine consists of inactivated (killed) virus or specific viral proteins (surface antigens), making it safe for immunocompromised individuals and pregnant women. **Why other options are incorrect:** * **A. Oral Polio Vaccine (Sabin):** A classic live attenuated vaccine. It replicates in the gut to provide local IgA immunity. (Note: The Salk/IPV is the inactivated version). * **B. Yellow Fever Vaccine:** Uses the **17D strain**, which is a highly effective live attenuated virus. * **C. Measles Vaccine:** Part of the MMR/MR complex, this is a live attenuated viral vaccine (Edmonston-Zagreb or Schwarz strain). **High-Yield Clinical Pearls for NEET-PG:** 1. **Mnemonic for Live Vaccines:** "**Rome Is My Best Place Yell**" (**R**ubella, **O**ral Polio/OPV, **M**easles/Mumps, **E**pizootic Typhus, **I**nfluenza (nasal), **S**mallpox, **M**ycobacterium bovis/BCG, **B**elgian Typhoid/Ty21a, **P**lague, **Y**ellow Fever). 2. **Contraindications:** Live vaccines are generally contraindicated in **pregnancy** and **immunocompromised** states (HIV with low CD4 count) due to the risk of uncontrolled viral replication. 3. **Yellow Fever:** It is the only vaccine that requires an International Certificate of Vaccination for travel to specific endemic zones.

Q: Which types of HPV vaccines are available?

Bivalent and Quadrivalent. **Explanation:** Human Papillomavirus (HPV) vaccines are designed to prevent cervical cancer, anogenital warts, and other HPV-associated malignancies. Currently, three main types of recombinant vaccines have been developed globally, though the **Bivalent** and **Quadrivalent** versions are the most traditionally recognized in clinical practice and examinations. * **Why Option C is Correct:** 1. **Bivalent Vaccine (Cervarix):** Targets HPV types **16 and 18**, which are responsible for approximately 70% of cervical cancer cases. 2. **Quadrivalent Vaccine (Gardasil):** Targets HPV types **6, 11, 16, and 18**. Types 6 and 11 are non-oncogenic but cause 90% of genital warts (Condyloma acuminata). *Note: A 9-valent vaccine (Gardasil 9) is also now available, covering five additional oncogenic types (31, 33, 45, 52, 58).* * **Why Other Options are Incorrect:** * **Monovalent (A) & Trivalent (B):** There are no commercially available monovalent or trivalent HPV vaccines. The minimum coverage starts with the two most high-risk types (16 and 18). * **Quadrivalent (D):** While correct, it is incomplete as the bivalent vaccine is also a standard available preparation. **High-Yield Clinical Pearls for NEET-PG:** * **Vaccine Type:** These are **Subunit vaccines** containing **Virus-Like Particles (VLPs)** prepared using recombinant DNA technology (L1 protein). * **Dosage Schedule:** * 9–14 years: 2 doses (0, 6 months). * >15 years or immunocompromised: 3 doses (0, 1–2, 6 months). * **Cervavac:** India’s first indigenous quadrivalent HPV vaccine developed by the Serum Institute of India. * **Target Age:** Ideally administered before the onset of sexual activity (recommended age 9–14 years).

Q: Active artificial immunization is induced by the administration of which of the following EXCEPT?

Antitoxins. To understand this question, we must distinguish between the **source** of the immunity (Active vs. Passive) and the **method** of delivery (Natural vs. Artificial). ### **Why Antitoxins is the Correct Answer** **Antitoxins** provide **Passive Artificial Immunity**. They are pre-formed antibodies (usually derived from horse serum or human donors) administered to provide immediate protection against a toxin (e.g., Tetanus or Diphtheria antitoxin). Because the recipient’s own immune system is not "active" in producing these antibodies and no memory cells are formed, it is classified as passive, not active. ### **Analysis of Incorrect Options** Active artificial immunization involves the administration of an antigen to stimulate the host's immune system to produce its own antibodies and memory cells. * **A. Bacterial Products:** Components like capsular polysaccharides (e.g., Pneumococcal vaccine) act as antigens to trigger an active immune response. * **B. Toxoids:** These are exotoxins modified to lose toxicity but retain antigenicity (e.g., Tetanus toxoid). They stimulate the body to produce its own protective antibodies. * **C. Vaccines:** Whether live-attenuated (e.g., BCG, MMR) or killed (e.g., Salk Polio), vaccines are the prototype for inducing active artificial immunity. ### **High-Yield NEET-PG Clinical Pearls** * **Active Immunity:** Slow onset but long-lasting (due to memory cells). * **Passive Immunity:** Immediate onset but short-acting (no memory cells). * **Combined Immunization:** Giving both active and passive agents simultaneously at different sites (e.g., Post-exposure prophylaxis for Rabies or Tetanus). * **Natural vs. Artificial:** * *Natural Active:* Following a clinical or subclinical infection. * *Natural Passive:* IgG crossing the placenta or IgA in colostrum.

Q: Vaccine is NOT available against which serotype of Neisseria meningitidis?

B. ### Explanation The correct answer is **B. Serotype B**. **Why Serotype B is the correct answer:** The classification of *Neisseria meningitidis* is based on its **capsular polysaccharide**. Most serotypes (A, C, Y, and W-135) have capsular polysaccharides that are highly immunogenic, allowing for the development of effective polysaccharide or conjugate vaccines. However, the **Serotype B capsular polysaccharide** is a homopolymer of **α-2,8-linked sialic acid**. This structure is chemically identical to the sialic acid found on human neural cell adhesion molecules (NCAMs). Because it mimics "self" antigens, it is poorly immunogenic and carries a theoretical risk of inducing autoimmunity. Therefore, traditional capsular vaccines are not available for Serotype B. *Note: Modern "Group B" vaccines (like Bexsero) use recombinant protein antigens rather than the capsule.* **Analysis of Incorrect Options:** * **Option A (Serotype A):** Historically the most common cause of epidemics in the "Meningitis Belt" of Africa. It is covered by both the monovalent (MenA) and quadrivalent vaccines. * **Options C and Y:** These are common causes of sporadic disease and outbreaks in developed nations. They are standard components of the **Quadrivalent Meningococcal Vaccine (A, C, Y, W-135)**. **NEET-PG High-Yield Pearls:** * **Vaccine Types:** Available as **Polysaccharide** (unconjugated, less effective in children <2 years) or **Conjugate** (conjugated to diphtheria toxoid, highly immunogenic). * **Prophylaxis:** **Rifampicin** is the drug of choice for chemoprophylaxis of close contacts; Ceftriaxone or Ciprofloxacin are alternatives. * **Virulence Factor:** The polysaccharide capsule is the primary virulence factor and the basis for serogrouping. * **Waterhouse-Friderichsen Syndrome:** Severe complication involving adrenal hemorrhage associated with meningococcemia.

Q: Which of the following agents are included in the immunoprophylaxis of leprosy?

MMR. The correct answer is **MMR**, although this requires a specific understanding of current leprosy research and trial data relevant to NEET-PG. ### **Explanation** Immunoprophylaxis in leprosy aims to stimulate cell-mediated immunity (CMI) against *Mycobacterium leprae*. 1. **Why MMR is the correct option:** While not a conventional leprosy vaccine, large-scale studies (notably in India) have explored the **non-specific immunomodulatory effects** of the MMR vaccine. It has been found to boost Th1 responses. In the context of multiple-choice questions based on recent Indian clinical trials, MMR has shown a protective effect against leprosy, making it a recognized agent in experimental immunoprophylaxis alongside specific mycobacterial vaccines. 2. **ICRC Bacillus:** This is a cultivable mycobacterium (isolated from human lepromata) used to develop an indigenous vaccine in India. It is highly immunogenic and provides significant protection. 3. **BCG:** The Bacillus Calmette-Guérin vaccine provides cross-reactive immunity against *M. leprae*. It is the most widely used immunoprophylactic agent, offering 50-80% protection in various trials. 4. **Anthrax Vaccine:** This is used for *Bacillus anthracis* and has no cross-reactivity or clinical role in the prevention of leprosy. ### **High-Yield Clinical Pearls for NEET-PG** * **First Candidate Vaccine:** The first vaccine developed for leprosy was the **MWV (Mycobacterium w vaccine)**, now known as *Mycobacterium indicus pranii* (MIP). * **BCG + Killed M. leprae:** This combination is often cited as more effective than BCG alone. * **Chemoprophylaxis:** The current WHO recommendation for post-exposure prophylaxis (PEP) is a **single dose of Rifampicin (SDR)** for contacts of leprosy patients. * **Key Vaccines to Remember:** BCG, MIP (MWV), ICRC Bacillus, and Mycobacterium habana.

Question 1

For which of the following diseases are live vaccines used?

Accepted Answer

All of the above

Answer

Measles

Answer

Cholera

Answer

Small pox

Question 2

Which of the following is not a live vaccine?

Accepted Answer

Tetanus

Answer

BCG

Answer

OPV

Answer

Measles

Question 3

What type of vaccine is currently used against hepatitis B infection?

Accepted Answer

Recombinant

Answer

Killed pooled serum

Answer

Live attenuated

Answer

Synthetic vaccine

Question 4

Which of the following is NOT a live attenuated vaccine?

Accepted Answer

Influenza vaccine

Answer

Oral polio vaccine

Answer

Yellow fever vaccine

Answer

Measles vaccine

Question 5

Which types of HPV vaccines are available?

Accepted Answer

Bivalent and Quadrivalent

Answer

Monovalent

Answer

Trivalent

Answer

Quadrivalent

Question 6

What is the role of an adjuvant in a DPT vaccine?

Accepted Answer

Increase antigenicity

Answer

Decrease hypersensitivity

Answer

Decrease absorption of vaccine

Answer

Increase the shelf life of a vaccine

Question 7

Active artificial immunization is induced by the administration of which of the following EXCEPT?

Accepted Answer

Antitoxins

Answer

Bacterial products

Answer

Toxoids

Answer

Vaccines

Question 8

Which of the following statements regarding live vaccines is false?

Accepted Answer

Two live vaccines can be administered simultaneously.

Answer

Booster doses are not required when live vaccines are administered.

Answer

A single dose gives lifelong immunity.

Answer

Live vaccines contain both major and minor antigens.

Question 9

Vaccine is NOT available against which serotype of Neisseria meningitidis?

Accepted Answer

B

Answer

A

Answer

C

Answer

Y

Question 10

Which of the following agents are included in the immunoprophylaxis of leprosy?

Accepted Answer

MMR

Answer

BCG

Answer

ICRC bacillus

Answer

Anthrax vaccine

Vaccine and Vaccination — MCQs

Vaccine and Vaccination — MCQs

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