Vaccine types and classification MCQs With Answer

Introduction: Vaccine types and classification MCQs With Answer is a focused quiz resource tailored for M.Pharm students studying Immunotechnology. This blog provides 20 carefully designed multiple-choice questions that cover core vaccine platforms—live attenuated, inactivated, subunit, toxoid, conjugate, viral vectors, VLP, DNA/RNA—and key concepts such as adjuvants, cold chain, immunogenicity in infants, reverse vaccinology and prime-boost strategies. Questions emphasize mechanistic understanding, formulation and regulatory-relevant distinctions to deepen conceptual clarity and aid exam preparation. Each MCQ includes plausible distractors and the correct answer to help students evaluate strengths and limitations of different vaccine types and their practical implications in pharmaceutical practice and research.

Q1. Which of the following is an example of a live attenuated vaccine?

• Inactivated polio vaccine (IPV)
• Recombinant hepatitis B vaccine
• BCG (Bacillus Calmette–Guérin)
• Toxoid vaccine for tetanus

Correct Answer: BCG (Bacillus Calmette–Guérin)

Q2. Which chemical is most commonly used historically to inactivate pathogens for whole-cell inactivated vaccines?

• Formaldehyde
• Sodium hypochlorite
• Ethanol
• Glyphosate

Correct Answer: Formaldehyde

Q3. What is the primary immunological purpose of conjugating a polysaccharide antigen to a carrier protein?

• To reduce antigenicity of the polysaccharide
• To convert a T-independent response into a T-dependent response
• To make the vaccine thermostable
• To target antigens to the innate immune system exclusively

Correct Answer: To convert a T-independent response into a T-dependent response

Q4. Which vaccine type is best represented by diphtheria and tetanus components?

• Subunit recombinant vaccine
• Toxoid vaccine
• Live attenuated vaccine
• Polysaccharide vaccine

Correct Answer: Toxoid vaccine

Q5. Which vaccine platform is based on self-assembling viral proteins that mimic the native virus structure without genetic material?

• Conjugate vaccine
• Virus-like particle (VLP) vaccine such as HPV vaccine
• DNA plasmid vaccine
• Inactivated whole-cell vaccine

Correct Answer: Virus-like particle (VLP) vaccine such as HPV vaccine

Q6. The principal mechanism by which mRNA vaccines elicit immunity is:

• Delivery of viral proteins directly to antigen-presenting cells
• Introduction of DNA that integrates into the host genome
• Delivery of mRNA encoding the antigen inside lipid nanoparticles leading to in situ antigen expression
• Presentation of inactivated whole virus to B cells

Correct Answer: Delivery of mRNA encoding the antigen inside lipid nanoparticles leading to in situ antigen expression

Q7. Adenovirus-based vaccines are an example of which vaccine class?

• Polysaccharide vaccine
• Recombinant protein subunit vaccine
• Viral vector vaccine
• Toxoid vaccine

Correct Answer: Viral vector vaccine

Q8. Which category of vaccines generally requires the most stringent cold chain maintenance to preserve viability?

• Inactivated whole-cell vaccines
• Live-attenuated vaccines
• Subunit recombinant vaccines
• Toxoid vaccines

Correct Answer: Live-attenuated vaccines

Q9. In veterinary and some human vaccine contexts, the acronym DIVA refers to:

• Direct Intramuscular Vaccine Administration
• Differentiating Infected from Vaccinated Animals
• Determinant-Induced Variable Antigenicity
• Double Inactivated Viral Antigen

Correct Answer: Differentiating Infected from Vaccinated Animals

Q10. Which adjuvant has been used for decades in licensed human vaccines to enhance antibody responses?

• Aluminum salts (alum)
• CpG oligodeoxynucleotides exclusively
• Squalene without emulsifiers
• Complete Freund’s adjuvant

Correct Answer: Aluminum salts (alum)

Q11. Which laboratory assay is most appropriate to measure functional neutralizing antibody responses as a correlate of vaccine potency?

• Western blot
• Enzyme-linked immunosorbent assay (ELISA) measuring total IgG
• Neutralization assay (virus neutralization test)
• Polymerase chain reaction (PCR) for antigen DNA

Correct Answer: Neutralization assay (virus neutralization test)

Q12. Reverse vaccinology primarily uses which resource to identify candidate vaccine antigens?

• High-throughput serology from convalescent patients
• Pathogen genome and bioinformatic analysis
• Traditional attenuation by serial passage
• Random peptide library screening only

Correct Answer: Pathogen genome and bioinformatic analysis

Q13. Which vaccine approach is most likely to elicit strong mucosal IgA responses when administered orally?

• Inactivated intramuscular vaccines
• Subunit protein vaccines delivered intradermally
• Live attenuated oral vaccines (e.g., oral polio vaccine)
• Toxoid vaccines given intramuscularly

Correct Answer: Live attenuated oral vaccines (e.g., oral polio vaccine)

Q14. Which carrier protein is commonly used for conjugate vaccines to enhance T-cell help?

• Bovine serum albumin (BSA)
• CRM197 (a non-toxic diphtheria toxin mutant)
• Ovalbumin
• Keyhole limpet hemocyanin (KLH) exclusively

Correct Answer: CRM197 (a non-toxic diphtheria toxin mutant)

Q15. Why are plain polysaccharide vaccines generally ineffective in infants under 2 years of age?

• Infants lack the innate immune system
• Polysaccharides are degraded too quickly in infants
• They elicit T-independent B-cell responses which infants cannot mount effectively
• Infants have pre-existing tolerance to polysaccharides

Correct Answer: They elicit T-independent B-cell responses which infants cannot mount effectively

Q16. Which vaccine platform demonstrated the fastest design-to-clinic timeline during recent pandemics due to its synthetic manufacturing process?

• Live attenuated virus production
• mRNA vaccine platforms
• Egg-based inactivated vaccines
• Conjugate polysaccharide vaccines

Correct Answer: mRNA vaccine platforms

Q17. A heterologous prime-boost vaccination strategy is used primarily to:

• Reduce the number of vaccine doses below one
• Broaden or enhance the magnitude and quality of the immune response
• Ensure vaccine components physically mix in the same vial
• Avoid the need for adjuvants entirely

Correct Answer: Broaden or enhance the magnitude and quality of the immune response

Q18. Which formulation change is most commonly associated with increased local reactogenicity in human vaccines?

• Removal of preservative
• Formulation with adjuvants such as oil-in-water emulsions or alum
• Lowering antigen dose substantially
• Using saline-only placebo

Correct Answer: Formulation with adjuvants such as oil-in-water emulsions or alum

Q19. Which of the following is NOT considered a vaccine type or platform?

• Live attenuated vaccine
• Inactivated whole-cell vaccine
• Toxoid vaccine
• Monoclonal antibody therapy

Correct Answer: Monoclonal antibody therapy

Q20. Which formulation or manufacturing strategy is frequently used to improve thermostability and shelf life of vaccines for easier distribution?

• Lyophilization (freeze-drying)
• Increasing pH to alkaline extremes
• Removing buffering agents completely
• Storing at room temperature with no stabilizers

Correct Answer: Lyophilization (freeze-drying)

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