Q.1 Which of the following is a primary goal of vaccine development?
Increase vaccine price
Reduce the need for herd immunity
Provide safe and effective protection against a specific pathogen
Eliminate the need for cold chain storage
Explanation - The fundamental aim of vaccine development is to elicit a protective immune response that prevents disease without causing adverse effects.
Correct answer is: Provide safe and effective protection against a specific pathogen
Q.2 What type of vaccine uses a killed version of the virus?
Live attenuated
Inactivated
mRNA
DNA
Explanation - Inactivated or killed vaccines contain viruses that have been inactivated so they cannot replicate, providing antigenic exposure without infection.
Correct answer is: Inactivated
Q.3 Adjuvants in vaccines primarily serve to:
Preserve the vaccine at room temperature
Increase the amount of antigen used
Enhance the immune response to the antigen
Provide a stabilizing buffer
Explanation - Adjuvants boost the immunogenicity of antigens, often allowing for dose sparing and stronger, longer-lasting immunity.
Correct answer is: Enhance the immune response to the antigen
Q.4 Which of the following is NOT a typical phase of clinical trials?
Phase I
Phase II
Phase III
Phase V
Explanation - Clinical trials are divided into Phase I, II, and III. Phase IV occurs after approval for post-marketing surveillance.
Correct answer is: Phase V
Q.5 mRNA vaccines rely on cellular machinery to produce:
DNA antigens
Proteins encoded by the mRNA
Viral vectors
Whole inactivated viruses
Explanation - mRNA vaccines deliver genetic instructions that host cells translate into antigens, triggering an immune response.
Correct answer is: Proteins encoded by the mRNA
Q.6 A viral vector vaccine uses:
A killed virus
An inactivated virus
A harmless virus carrying genetic material
Synthetic peptides
Explanation - Viral vectors are engineered to be replication-deficient while delivering antigenic genes to host cells.
Correct answer is: A harmless virus carrying genetic material
Q.7 Which regulatory body typically grants emergency use authorization for a new vaccine?
WHO
FDA
CDC
ECDC
Explanation - In the U.S., the Food and Drug Administration (FDA) can issue Emergency Use Authorization (EUA) for vaccines during public health emergencies.
Correct answer is: FDA
Q.8 Herd immunity is achieved when:
Everyone receives a live attenuated vaccine
A significant portion of the population is immune to a disease
Vaccines are only given to children
Only the elderly are vaccinated
Explanation - High immunity levels reduce overall disease spread, protecting even those who are not fully immune.
Correct answer is: A significant portion of the population is immune to a disease
Q.9 In vaccine formulation, the buffer system primarily ensures:
Antigen stability at high temperatures
Neutral pH for optimal antigen presentation
Inclusion of adjuvant
Removal of residual host cell proteins
Explanation - Buffers maintain physiological pH, which preserves antigen structure and function during storage and administration.
Correct answer is: Neutral pH for optimal antigen presentation
Q.10 Which component of a vaccine is typically responsible for stimulating cellular immunity?
Antibody
T-helper cells
Antigen presented via MHC class I
Adjuvant
Explanation - Antigens processed through the endogenous pathway are presented on MHC I molecules, activating CD8+ cytotoxic T cells.
Correct answer is: Antigen presented via MHC class I
Q.11 The 'cold chain' requirement in vaccine distribution refers to:
A chain of command for approval
Storing vaccines at room temperature only
Maintaining vaccines at low temperatures throughout transport and storage
A specific type of refrigeration unit
Explanation - Many vaccines degrade if not stored within a specific temperature range, necessitating a cold chain logistics system.
Correct answer is: Maintaining vaccines at low temperatures throughout transport and storage
Q.12 DNA vaccines are designed to be:
Delivered via lipid nanoparticles
Integrated into the host genome
Expressed by host cell DNA after plasmid uptake
Killed bacterial spores
Explanation - Plasmid DNA enters host cells, where it is transcribed and translated into antigenic proteins that trigger immunity.
Correct answer is: Expressed by host cell DNA after plasmid uptake
Q.13 What is the main advantage of protein subunit vaccines?
No live components, reducing safety concerns
They are the most affordable
They require no adjuvants
They provide immediate immunity
Explanation - Subunit vaccines contain only specific protein pieces of the pathogen, offering a high safety profile with minimal risk of infection.
Correct answer is: No live components, reducing safety concerns
Q.14 Which of the following is a key step in the GMP (Good Manufacturing Practice) for vaccine production?
Random batch sampling
Batch record documentation
In-situ antigen synthesis
Use of untested reagents
Explanation - GMP requires meticulous record-keeping to ensure traceability, quality, and regulatory compliance.
Correct answer is: Batch record documentation
Q.15 The term 'epitope' refers to:
The entire antigenic protein
The region of an antigen that is recognized by a specific antibody or T-cell receptor
A vaccine's adjuvant
The manufacturing facility
Explanation - Epitope is the specific part of an antigen that is bound by immune receptors, critical for vaccine design.
Correct answer is: The region of an antigen that is recognized by a specific antibody or T-cell receptor
Q.16 What is the purpose of a 'challenge study' in vaccine trials?
To evaluate the vaccine's effect against a live pathogen in a controlled setting
To determine the vaccine's shelf life
To assess manufacturing scale-up
To test the vaccine's stability at high temperatures
Explanation - Challenge studies expose volunteers to the pathogen after vaccination to directly measure protection efficacy.
Correct answer is: To evaluate the vaccine's effect against a live pathogen in a controlled setting
Q.17 Which technique is commonly used for the purification of recombinant viral proteins in vaccine production?
Ion exchange chromatography
Gel electrophoresis
PCR amplification
Mass spectrometry
Explanation - Ion exchange chromatography separates proteins based on charge and is widely used for purifying vaccine antigens.
Correct answer is: Ion exchange chromatography
Q.18 A major advantage of using mRNA vaccines is that:
They can be stored at room temperature indefinitely
They do not require a cold chain
They can be rapidly designed and synthesized
They induce a stronger humoral response than all other types
Explanation - mRNA vaccines can be quickly engineered once the viral sequence is known, accelerating development timelines.
Correct answer is: They can be rapidly designed and synthesized
Q.19 Which of the following is NOT typically monitored during a Phase III vaccine trial?
Efficacy endpoints
Adverse event reporting
In vitro antigen stability
Immunogenicity biomarkers
Explanation - Phase III focuses on real-world efficacy and safety, not laboratory stability studies, which are done earlier.
Correct answer is: In vitro antigen stability
Q.20 Live attenuated vaccines are formulated to:
Contain no viral particles
Be killed but still immunogenic
Use weakened viruses that can replicate minimally
Use synthetic peptides
Explanation - Attenuated viruses maintain limited replication capability, stimulating robust immunity while minimizing disease risk.
Correct answer is: Use weakened viruses that can replicate minimally
Q.21 Which of the following best describes a 'platform technology' in vaccine development?
A single antigen used for all vaccines
A production method that can be adapted to different antigens
A type of adjuvant
A storage facility
Explanation - Platform technologies, like mRNA or viral vectors, provide a modular basis for quickly creating new vaccines.
Correct answer is: A production method that can be adapted to different antigens
Q.22 Which of the following is a typical end product of a vaccine manufacturing process?
DNA plasmid
Viral vector
Formulated vaccine dose
Cell line culture medium
Explanation - The final product is the formulated dose ready for administration, not the intermediate components.
Correct answer is: Formulated vaccine dose
Q.23 In the context of vaccine supply chain, what does 'buffer stock' refer to?
Extra vaccine doses kept to meet unexpected demand
A chemical used in formulation
A storage container
A type of preservative
Explanation - Buffer stock ensures availability during surges or disruptions in supply.
Correct answer is: Extra vaccine doses kept to meet unexpected demand
Q.24 Which of the following is a key challenge in global vaccine distribution?
High rates of vaccine side effects worldwide
Uniform acceptance across cultures
Universal availability of cold chain infrastructure
Limited production capacity of all vaccines
Explanation - Cold chain logistics are critical but often lacking in low-resource settings, hindering effective distribution.
Correct answer is: Universal availability of cold chain infrastructure
Q.25 Which analytical method is commonly used to verify the purity of recombinant proteins in vaccines?
Western blotting
Thin-layer chromatography
High-performance liquid chromatography (HPLC)
Northern blotting
Explanation - HPLC provides precise separation and quantification of protein purity in vaccine preparations.
Correct answer is: High-performance liquid chromatography (HPLC)
Q.26 A vaccine that uses a non-replicating viral vector is considered:
Live attenuated
Inactivated
Subunit
Viral vector (non-replicating)
Explanation - Non-replicating vectors deliver genetic material but cannot propagate, reducing safety concerns.
Correct answer is: Viral vector (non-replicating)
Q.27 The 'WHO International Standard' for a vaccine refers to:
A globally recognized potency reference
The most expensive vaccine brand
The largest vaccine manufacturer
A standard temperature for storage
Explanation - International standards enable cross-laboratory potency comparisons and quality control.
Correct answer is: A globally recognized potency reference
Q.28 Which of the following best describes a 'prime-boost' strategy?
Using a single vaccine dose twice in a row
Administering a live vaccine followed by a killed one
Giving an initial vaccine dose (prime) and a subsequent dose (boost) to enhance immunity
Testing the vaccine on one group and then boosting the entire population
Explanation - Prime-boost regimens aim to achieve stronger and longer-lasting immunity by stimulating the immune system multiple times.
Correct answer is: Giving an initial vaccine dose (prime) and a subsequent dose (boost) to enhance immunity
Q.29 What does 'sterility assurance level' (SAL) represent in vaccine manufacturing?
The maximum allowed temperature during production
The probability of a product being free of viable microorganisms
The time needed for vaccine to become sterile
The amount of preservative used
Explanation - SAL quantifies the likelihood that a batch contains no viable microorganisms, ensuring product safety.
Correct answer is: The probability of a product being free of viable microorganisms
Q.30 The term 'potency' in vaccine testing refers to:
The vaccine's shelf life
The maximum safe dose
The ability to induce an immune response at a specific dose
The amount of adjuvant present
Explanation - Potency tests measure the biological activity of a vaccine, ensuring each dose meets efficacy criteria.
Correct answer is: The ability to induce an immune response at a specific dose
Q.31 Which of the following is an example of a 'protein-based' vaccine?
Bacillus Calmette–Guérin (BCG)
Measles–Mumps–Rubella (MMR)
Influenza subunit vaccine
Polio inactivated vaccine
Explanation - Protein-based (subunit) vaccines contain purified viral proteins rather than whole viruses or attenuated organisms.
Correct answer is: Influenza subunit vaccine
Q.32 Which of the following is a critical component for stabilizing mRNA vaccines during storage?
Polyethylene glycol
Lipid nanoparticles
Calcium chloride
Sodium chloride
Explanation - Lipid nanoparticles encapsulate mRNA, protecting it from degradation and facilitating cellular uptake.
Correct answer is: Lipid nanoparticles
Q.33 The 'cold chain' for mRNA vaccines typically requires:
Room temperature
4°C
-20°C
-80°C
Explanation - mRNA vaccines are highly temperature-sensitive and usually stored at ultra-low temperatures, like -80°C.
Correct answer is: -80°C
Q.34 Which of the following is a commonly used adjuvant in licensed vaccines?
Aluminum salts (alum)
Glutaraldehyde
Polyethylene glycol
Tween 20
Explanation - Alum is the most widely used adjuvant, enhancing humoral immune responses in many vaccines.
Correct answer is: Aluminum salts (alum)
Q.35 In vaccine nomenclature, what does 'DTP' stand for?
Diphtheria, Tetanus, Pertussis
Dengue, Typhoid, Polio
Dermatitis, Tuberculosis, Parvovirus
Dysentery, Tetanus, Pneumococcus
Explanation - DTP is a combination vaccine protecting against diphtheria, tetanus, and pertussis.
Correct answer is: Diphtheria, Tetanus, Pertussis
Q.36 Which of the following is NOT a typical component of a vaccine formulation?
Antigen
Adjuvant
Antibiotic
Buffer
Explanation - Vaccines normally do not contain antibiotics; they may contain preservatives instead.
Correct answer is: Antibiotic
Q.37 The principle of 'mosaic vaccines' involves:
Using the same antigen across different viruses
Incorporating multiple antigenic variants into one vaccine
Administering vaccines in a mosaic pattern in the body
Using a single adjuvant for multiple vaccines
Explanation - Mosaic vaccines aim to broaden protection by presenting diverse epitopes from various strains.
Correct answer is: Incorporating multiple antigenic variants into one vaccine
Q.38 What is the primary function of a 'fill-finish' operation in vaccine production?
Purify the antigen
Add stabilizers
Dispense the vaccine into final dosage forms
Validate the manufacturing process
Explanation - Fill-finish involves filling vials, syringes, or other containers with the final vaccine product.
Correct answer is: Dispense the vaccine into final dosage forms
Q.39 Which of the following best describes the 'reverse vaccinology' approach?
Starting from pathogen genome to identify antigens
Using live pathogens to generate immunity
Reversing the dosage schedule
Vaccinating against reverse mutations
Explanation - Reverse vaccinology uses genomic data to predict protective antigens before laboratory testing.
Correct answer is: Starting from pathogen genome to identify antigens
Q.40 Which of the following is a common challenge in the scalability of mRNA vaccine production?
Difficulty in extracting nucleic acids
High cost of lipid nanoparticles
Longer shelf life
Limited antigen selection
Explanation - Lipid nanoparticles are essential but expensive, affecting large-scale production costs.
Correct answer is: High cost of lipid nanoparticles
Q.41 What does 'sterility testing' aim to detect in a vaccine batch?
Presence of any residual antigen
Presence of viable microorganisms
Immunogenic potency
Chemical contaminants
Explanation - Sterility testing ensures that the final product is free from live bacterial or fungal contamination.
Correct answer is: Presence of viable microorganisms
Q.42 Which of the following is a regulatory pathway for a vaccine under expedited review in the U.S.?
Full review
Accelerated approval
Priority review
No review
Explanation - Priority review shortens the FDA's review time for products that offer significant therapeutic benefits.
Correct answer is: Priority review
Q.43 An inactivated influenza vaccine typically contains:
Live attenuated viruses
Whole killed viruses
Recombinant hemagglutinin proteins
DNA plasmids
Explanation - Inactivated vaccines use viruses that have been killed, providing safety while presenting full antigenic profiles.
Correct answer is: Whole killed viruses
Q.44 Which of the following is a primary immune response indicator in vaccine trials?
Seroconversion rate
Blood pressure change
Heart rate variability
Body temperature
Explanation - Seroconversion refers to the development of detectable specific antibodies, indicating an immune response.
Correct answer is: Seroconversion rate
Q.45 Which of the following is a key advantage of using DNA vaccines?
They can be stored at room temperature for long periods
They trigger a strong antibody response without cellular immunity
They are stable and can be produced quickly
They do not require regulatory approval
Explanation - DNA vaccines are relatively stable and can be synthesized rapidly, facilitating quick response to emerging pathogens.
Correct answer is: They are stable and can be produced quickly
Q.46 Which of the following is the most common type of vaccine used to protect infants in many countries?
Live attenuated
Inactivated
Subunit
Whole organism
Explanation - Inactivated vaccines are preferred for infants due to safety and the immature immune system.
Correct answer is: Inactivated
Q.47 The term 'epitope mapping' refers to:
Identifying the best storage temperature
Determining the exact location of epitopes on an antigen
Mapping vaccine distribution routes
Mapping immune system cell types
Explanation - Epitope mapping identifies the precise amino acid sequences recognized by immune receptors.
Correct answer is: Determining the exact location of epitopes on an antigen
Q.48 What is a key reason for using 'adjuvants' in subunit vaccines?
To reduce vaccine cost
To increase the antigen's immunogenicity
To neutralize the vaccine
To preserve the vaccine at high temperatures
Explanation - Subunit vaccines have lower immunogenicity, so adjuvants help stimulate a stronger immune response.
Correct answer is: To increase the antigen's immunogenicity
Q.49 Which of the following is a common method for measuring antibody titers in vaccine studies?
ELISA
Western blot
PCR
Flow cytometry
Explanation - ELISA (enzyme-linked immunosorbent assay) quantifies specific antibodies in serum samples.
Correct answer is: ELISA
Q.50 The 'WHO prequalification' process ensures that a vaccine:
Is sold at the lowest possible price
Is manufactured in a WHO facility
Meets global standards of quality, safety, and efficacy
Contains no adjuvants
Explanation - WHO prequalification evaluates vaccines to ensure they meet international standards for distribution in low- and middle-income countries.
Correct answer is: Meets global standards of quality, safety, and efficacy
Q.51 Which of the following best describes the 'cold chain' for a protein subunit vaccine?
Storage at room temperature only
Storage at 2–8°C throughout the supply chain
Storage at -20°C only
No temperature control needed
Explanation - Protein subunit vaccines typically require refrigeration at 2–8°C to maintain stability.
Correct answer is: Storage at 2–8°C throughout the supply chain
Q.52 In vaccine quality control, 'in-process controls' are used to:
Verify final product purity
Monitor critical parameters during manufacturing
Determine shelf life
Calculate dosage errors
Explanation - In-process controls assess parameters like temperature, pH, and product concentration during production.
Correct answer is: Monitor critical parameters during manufacturing
Q.53 Which of the following is a main advantage of using viral vectors for vaccine delivery?
They are completely inert
They can be easily visualized under a microscope
They can induce strong cellular immunity
They eliminate the need for adjuvants
Explanation - Viral vectors mimic natural infection, stimulating both humoral and cellular immune responses.
Correct answer is: They can induce strong cellular immunity
Q.54 What does the term 'seroprotection' refer to in vaccine studies?
The presence of antibodies that provide protective levels of immunity
The percentage of vaccine recipients who experience side effects
The duration of vaccine efficacy
The ratio of B-cells to T-cells after vaccination
Explanation - Seroprotection indicates a serum antibody concentration that is considered protective against infection.
Correct answer is: The presence of antibodies that provide protective levels of immunity
Q.55 Which of the following best explains 'cross-reactivity' in vaccine-induced immunity?
The vaccine induces immunity to unrelated pathogens
The immune response is limited to the exact antigen
The vaccine triggers immune response to similar epitopes on different pathogens
The vaccine's antigen is degraded in the body
Explanation - Cross-reactivity occurs when immune receptors recognize similar antigenic determinants across multiple pathogens.
Correct answer is: The vaccine triggers immune response to similar epitopes on different pathogens
Q.56 Which of the following is a typical component of a vaccine's 'fill-finish' process?
Antigen purification
Vaccine formulation in pre-filled syringes
Genetic sequencing of the pathogen
Cell culture expansion
Explanation - Fill-finish converts the liquid vaccine into finished dosage forms such as vials or pre-filled syringes.
Correct answer is: Vaccine formulation in pre-filled syringes
Q.57 What is the primary purpose of using 'culture media' in vaccine production?
To sterilize the vaccine
To grow the vaccine-producing cells or viruses
To preserve the vaccine
To provide adjuvants
Explanation - Culture media supplies nutrients needed for the proliferation of cells or viruses used in vaccine manufacture.
Correct answer is: To grow the vaccine-producing cells or viruses
Q.58 Which of the following is a major factor in determining vaccine immunogenicity?
The color of the vaccine
The dosage form (vial vs syringe)
The route of administration
The time of day the vaccine is taken
Explanation - Intramuscular, subcutaneous, oral, and intranasal routes can significantly influence the immune response.
Correct answer is: The route of administration
Q.59 Which of the following best describes a 'biological safety level' (BSL) in vaccine labs?
The number of safety protocols required
The temperature control level
The level of containment needed for handling pathogens
The storage cost for vaccines
Explanation - BSL designates the containment measures appropriate for different classes of biological agents.
Correct answer is: The level of containment needed for handling pathogens
Q.60 What is the purpose of a 'pharmacokinetic study' in the context of a vaccine?
To measure how long the vaccine remains in the body
To assess the vaccine's potency
To determine the cost of vaccine production
To identify side effects
Explanation - Pharmacokinetics studies the absorption, distribution, metabolism, and excretion of vaccine components.
Correct answer is: To measure how long the vaccine remains in the body
Q.61 Which of the following is a common method for delivering mRNA into cells?
Transfection with lipid nanoparticles
Direct injection into the bloodstream
Topical application on skin
Oral administration
Explanation - Lipid nanoparticles encapsulate mRNA and facilitate its uptake by host cells.
Correct answer is: Transfection with lipid nanoparticles
Q.62 In vaccine development, what does 'strain selection' involve?
Choosing the cheapest manufacturing partner
Selecting the viral or bacterial strain to use as antigen
Determining the best storage temperature
Choosing the most potent adjuvant
Explanation - Strain selection identifies the specific isolate that provides optimal immunogenicity and safety.
Correct answer is: Selecting the viral or bacterial strain to use as antigen
Q.63 Which of the following best describes the 'mosaic' approach to vaccine design?
Using a single antigen for all viruses
Combining multiple antigenic variants into one vaccine
Developing a vaccine with a mosaic pattern on the vial
Using only mosaic adjuvants
Explanation - Mosaic vaccines include a diverse set of epitopes to broaden protection against multiple strains.
Correct answer is: Combining multiple antigenic variants into one vaccine
Q.64 Which of the following is a key element of a vaccine's 'quality assurance' (QA) program?
Random sampling of finished batches
Public announcement of manufacturing costs
Weekly budget reviews
Annual marketing plans
Explanation - QA ensures product consistency through sampling, testing, and documentation across production.
Correct answer is: Random sampling of finished batches
Q.65 A 'phase IV' study primarily focuses on:
Pre-clinical safety
Early-phase human trials
Post-marketing surveillance of vaccine safety and effectiveness
Manufacturing scale-up
Explanation - Phase IV monitors long-term safety and efficacy in a large population after approval.
Correct answer is: Post-marketing surveillance of vaccine safety and effectiveness
Q.66 Which of the following best describes 'heterologous prime-boost' in vaccine strategies?
Using the same vaccine formulation twice
Using different vaccine platforms for prime and boost
Prime only without a boost
Boosting with a placebo
Explanation - Heterologous prime-boost combines distinct vaccine modalities to maximize immune responses.
Correct answer is: Using different vaccine platforms for prime and boost
Q.67 Which of the following is an advantage of inactivated vaccines?
They can induce lifelong immunity automatically
They are safe for immunocompromised individuals
They do not require any adjuvants
They can be administered orally without a dose limit
Explanation - Since the pathogen cannot replicate, inactivated vaccines are safe for those with weakened immune systems.
Correct answer is: They are safe for immunocompromised individuals
Q.68 In vaccine trials, a 'double-blind' design means:
Neither participants nor investigators know which group receives the vaccine or placebo
Both participants and investigators know the assignment
Only participants are unaware of their assignment
Only investigators are unaware of the assignment
Explanation - Double-blind trials minimize bias by keeping both parties unaware of group allocations.
Correct answer is: Neither participants nor investigators know which group receives the vaccine or placebo
Q.69 Which of the following is a typical end-point in a Phase II vaccine trial?
Overall mortality rate in the general population
Safety profile and immunogenicity in a specific population
Shelf life determination
Cost of production analysis
Explanation - Phase II evaluates safety and immune responses in a larger but still limited group.
Correct answer is: Safety profile and immunogenicity in a specific population
Q.70 The 'WHO Global Vaccine Action Plan' primarily aims to:
Standardize vaccine pricing globally
Eliminate vaccine hesitancy worldwide
Ensure equitable access to essential vaccines
Create new vaccine platforms
Explanation - The Global Vaccine Action Plan focuses on universal vaccine coverage and access, especially in low-resource settings.
Correct answer is: Ensure equitable access to essential vaccines
Q.71 Which of the following is a standard measure of vaccine potency?
Antigen concentration per dose
Color of the vial
Time to produce the vaccine
Number of batches produced
Explanation - Potency tests verify that each dose contains the correct amount of antigen to elicit a response.
Correct answer is: Antigen concentration per dose
Q.72 What is the role of 'buffer capacity' in a vaccine formulation?
To maintain the vaccine's color
To preserve the vaccine's antigenicity by maintaining pH
To provide a preservative
To enhance the vaccine's potency
Explanation - Buffer capacity ensures the vaccine remains stable across a range of temperatures and conditions.
Correct answer is: To preserve the vaccine's antigenicity by maintaining pH
Q.73 Which of the following is a common method for measuring vaccine potency using live virus?
Hemagglutination inhibition assay
Virus neutralization assay
PCR amplification
Flow cytometry
Explanation - Virus neutralization assays assess the ability of antibodies to inhibit viral infectivity, a key potency indicator.
Correct answer is: Virus neutralization assay
Q.74 Which of the following best describes a 'multivalent' vaccine?
A vaccine that protects against a single pathogen
A vaccine that protects against multiple pathogens
A vaccine that uses multiple adjuvants
A vaccine that is delivered through multiple routes
Explanation - Multivalent vaccines contain antigens from more than one pathogen in a single formulation.
Correct answer is: A vaccine that protects against multiple pathogens
Q.75 Which of the following is a key advantage of DNA vaccines for rapid response to pandemics?
They can be administered orally
They can be stored at room temperature
They can be synthesized quickly once the genome is sequenced
They induce no cellular immunity
Explanation - DNA vaccines rely on plasmid construction, which can be rapidly done after pathogen sequencing.
Correct answer is: They can be synthesized quickly once the genome is sequenced
Q.76 Which of the following is NOT a typical component in a vaccine's 'fill-finish' step?
Sterile filtration
Vial filling
Packaging
Cell culture expansion
Explanation - Cell culture expansion occurs earlier during production, not during the final fill-finish stage.
Correct answer is: Cell culture expansion
Q.77 Which of the following best describes the 'cold chain' requirement for a DNA vaccine?
Storage at 4°C during distribution
Storage at -20°C during distribution
No temperature control needed
Storage at 20–25°C
Explanation - DNA vaccines are relatively stable but still require refrigeration to maintain integrity.
Correct answer is: Storage at 4°C during distribution
Q.78 Which of the following is a typical purpose of 'sterilization' in vaccine manufacturing?
To remove endotoxins from the vaccine
To eliminate viable microorganisms
To sterilize the storage containers only
To reduce the vaccine dose
Explanation - Sterilization ensures that the vaccine product is free from live bacterial or fungal contaminants.
Correct answer is: To eliminate viable microorganisms
Q.79 Which of the following is a key benefit of using adjuvants with subunit vaccines?
They eliminate the need for boosters
They increase the vaccine’s shelf life
They enhance the immune response to the small antigen
They remove the antigen entirely
Explanation - Subunit vaccines contain limited antigenic material; adjuvants help elicit a robust immune response.
Correct answer is: They enhance the immune response to the small antigen
Q.80 In the context of vaccine safety, a 'reactogenicity' assessment measures:
The vaccine’s ability to induce an immune response
The local or systemic reactions following vaccination
The manufacturing cost per dose
The vaccine’s shelf life
Explanation - Reactogenicity evaluates immediate adverse events such as pain, fever, or swelling after vaccination.
Correct answer is: The local or systemic reactions following vaccination
Q.81 Which of the following is a common reason for a vaccine's 'batch record' to be audited?
To confirm the vaccine’s potency
To verify that the vaccine was manufactured according to GMP
To analyze patient data
To calculate the vaccine price
Explanation - Batch record audits ensure compliance with Good Manufacturing Practices during production.
Correct answer is: To verify that the vaccine was manufactured according to GMP
Q.82 Which of the following is an advantage of using viral vectors for delivering antigens?
They are inherently inactivated
They can be stored at room temperature
They can mimic natural infection and trigger both humoral and cellular immunity
They do not require any purification steps
Explanation - Viral vectors stimulate strong cellular and humoral responses by delivering antigenic genes to host cells.
Correct answer is: They can mimic natural infection and trigger both humoral and cellular immunity
Q.83 Which of the following best describes a 'biologics' in the context of vaccines?
A chemical compound used as a drug
A product derived from living organisms used for therapeutic purposes
An industrial solvent
A type of synthetic polymer
Explanation - Vaccines are considered biologics because they are produced from biological systems.
Correct answer is: A product derived from living organisms used for therapeutic purposes
Q.84 In vaccine development, 'antigenic drift' refers to:
The gradual accumulation of mutations in the antigenic sites of a virus
The process of moving vaccine antigens between different cell lines
The reduction of vaccine potency over time
The change in vaccine storage temperature
Explanation - Antigenic drift can lead to decreased vaccine effectiveness if the vaccine does not match circulating strains.
Correct answer is: The gradual accumulation of mutations in the antigenic sites of a virus
Q.85 Which of the following is a typical component of an 'inactivated vaccine' formulation?
Live virus particles
Killed virus particles
Synthetic peptides
Genetic material
Explanation - Inactivated vaccines contain viruses that have been chemically or physically inactivated.
Correct answer is: Killed virus particles
Q.86 What is the purpose of a 'buffer system' in a vaccine?
To increase the vaccine’s potency
To maintain pH and stabilize the antigen
To provide an adjuvant
To reduce the vaccine dose
Explanation - Buffer systems preserve the physical and chemical stability of vaccine components.
Correct answer is: To maintain pH and stabilize the antigen
Q.87 Which of the following is a common method used to evaluate the stability of a vaccine?
Accelerated degradation testing at elevated temperatures
Counting the number of vials
Measuring the vaccine’s color
Checking the vaccine’s price
Explanation - Accelerated stability tests simulate long-term storage by exposing the product to higher temperatures.
Correct answer is: Accelerated degradation testing at elevated temperatures
Q.88 Which of the following is a typical characteristic of a 'live attenuated' vaccine?
It cannot replicate in the host
It can replicate but has reduced virulence
It uses a killed pathogen
It requires a high dose
Explanation - Live attenuated vaccines contain weakened organisms that can replicate, mimicking natural infection.
Correct answer is: It can replicate but has reduced virulence
Q.89 Which of the following is a typical role of the WHO in vaccine development?
Setting vaccine production quotas
Providing a global standard for vaccine efficacy
Funding vaccine production in high-income countries only
Setting vaccine manufacturing costs
Explanation - WHO establishes standards and guidelines to ensure vaccine quality and safety worldwide.
Correct answer is: Providing a global standard for vaccine efficacy
Q.90 Which of the following is a primary safety concern in subunit vaccines?
Uncontrolled viral replication
Potential for allergic reactions to adjuvants
Risk of insertional mutagenesis
Risk of producing live virus
Explanation - Subunit vaccines rely on adjuvants, which can sometimes cause hypersensitivity or allergic reactions.
Correct answer is: Potential for allergic reactions to adjuvants
Q.91 Which of the following is a key factor influencing the choice of vaccine delivery route?
The color of the vaccine vial
The cost of the vaccine
The immune response desired (e.g., mucosal vs systemic)
The brand of the syringe used
Explanation - The route of administration determines whether the immune response will be mucosal or systemic.
Correct answer is: The immune response desired (e.g., mucosal vs systemic)
Q.92 Which of the following is NOT a typical component of a vaccine's 'adjuvant' formulation?
Aluminum salts
Oil-in-water emulsions
Preservatives
Genetic plasmids
Explanation - Adjuvants are chemical or biological substances that enhance immunogenicity, not plasmids.
Correct answer is: Genetic plasmids
Q.93 Which of the following is a common measure of vaccine immunogenicity?
Serum IgG concentration
Number of vials shipped
Time to produce the vaccine
Vaccine color
Explanation - IgG titers are a key marker of humoral immunity following vaccination.
Correct answer is: Serum IgG concentration
Q.94 Which of the following best describes the purpose of a 'preclinical safety study'?
To test the vaccine in humans for the first time
To assess safety and toxicity in animal models
To evaluate vaccine pricing
To analyze market potential
Explanation - Preclinical studies evaluate safety before moving to human clinical trials.
Correct answer is: To assess safety and toxicity in animal models
Q.95 Which of the following is a typical challenge in vaccine formulation?
Choosing the right packaging color
Ensuring antigen stability during storage
Selecting a manufacturer
Deciding the price for consumers
Explanation - Maintaining antigen integrity during manufacturing and distribution is critical for vaccine efficacy.
Correct answer is: Ensuring antigen stability during storage
Q.96 Which of the following best describes the 'cold chain' for a protein subunit vaccine?
Storage at 2–8°C throughout the supply chain
Storage at -20°C throughout the supply chain
No temperature control required
Storage at 20–25°C
Explanation - Protein subunit vaccines typically require refrigeration at 2–8°C to remain stable.
Correct answer is: Storage at 2–8°C throughout the supply chain
Q.97 Which of the following best describes 'mRNA vaccine stability'?
mRNA is stable at room temperature indefinitely
mRNA must be stored at ultra-low temperatures, such as -80°C
mRNA can only be stored at -20°C
mRNA does not need any special storage
Explanation - mRNA molecules are highly labile and require ultra-low temperature storage to prevent degradation.
Correct answer is: mRNA must be stored at ultra-low temperatures, such as -80°C
Q.98 Which of the following is an example of a 'live attenuated' vaccine?
Polio inactivated vaccine
Measles, mumps, and rubella (MMR) vaccine
Hepatitis B vaccine
Influenza subunit vaccine
Explanation - MMR contains weakened live viruses that can replicate but are non-pathogenic.
Correct answer is: Measles, mumps, and rubella (MMR) vaccine
Q.99 Which of the following best describes the role of the 'GMP' (Good Manufacturing Practice) in vaccine production?
It sets the vaccine price
It ensures consistent quality and safety throughout manufacturing
It defines the marketing strategy
It determines the shelf life of a vaccine
Explanation - GMP standards govern all aspects of production to guarantee product safety and efficacy.
Correct answer is: It ensures consistent quality and safety throughout manufacturing
Q.100 Which of the following is a typical component of a vaccine's 'buffer'?
Sodium chloride
Aluminum hydroxide
Polysorbate 80
Sodium phosphate
Explanation - Sodium phosphate acts as a pH stabilizer in many vaccine formulations.
Correct answer is: Sodium phosphate
Q.101 What does the term 'antibody titer' refer to?
The number of vaccine vials in a batch
The concentration of specific antibodies in a sample
The age of the vaccine manufacturer
The amount of adjuvant per dose
Explanation - Antibody titer quantifies how many antibodies are present, indicating immune response magnitude.
Correct answer is: The concentration of specific antibodies in a sample
Q.102 Which of the following is a common reason for a vaccine to undergo a Phase III trial?
To evaluate safety in a small group of healthy volunteers
To confirm efficacy and monitor large-scale safety in the target population
To determine the vaccine's shelf life
To develop the manufacturing process
Explanation - Phase III trials assess effectiveness and safety in large, diverse populations.
Correct answer is: To confirm efficacy and monitor large-scale safety in the target population
Q.103 Which of the following is a typical measure used to assess the potency of a viral vaccine?
Hemagglutination inhibition assay
Potency assay via plaque reduction
Colorimetric assay
PCR-based quantification
Explanation - Plaque reduction neutralization tests determine how much antigen is required to neutralize virus infection.
Correct answer is: Potency assay via plaque reduction
Q.104 Which of the following best describes a 'heterologous prime-boost' vaccination strategy?
Using the same vaccine platform for both prime and boost
Using different vaccine platforms for prime and boost
Administering only a prime dose
Administering a booster dose that contains no antigen
Explanation - Heterologous prime-boost uses distinct vaccine types to maximize immunogenicity.
Correct answer is: Using different vaccine platforms for prime and boost
Q.105 What is a key advantage of using an 'inactivated' vaccine for elderly populations?
They provide stronger immunity than live vaccines
They eliminate the risk of infection
They can be administered without needles
They are cheaper to produce
Explanation - Elderly individuals often have weaker immune systems; inactivated vaccines pose no infection risk.
Correct answer is: They eliminate the risk of infection
Q.106 Which of the following is a potential risk associated with a 'live attenuated' vaccine?
Risk of reversion to a virulent form
Risk of immediate allergic reaction
Risk of rapid degradation
Risk of contamination with host DNA
Explanation - Live attenuated strains may occasionally revert to a more pathogenic form, posing safety concerns.
Correct answer is: Risk of reversion to a virulent form
Q.107 Which of the following is a typical component of a vaccine's 'fill-finish' operation?
Sterile filtration
Cell line expansion
Antigen purification
Genetic sequencing
Explanation - Fill-finish includes final filtration to ensure sterility before packaging.
Correct answer is: Sterile filtration
Q.108 Which of the following best describes a 'subunit' vaccine?
Contains live virus
Contains killed virus
Contains a fragment or subpart of the pathogen
Contains whole organism
Explanation - Subunit vaccines use isolated antigens rather than whole pathogens.
Correct answer is: Contains a fragment or subpart of the pathogen
Q.109 Which of the following is a common method for measuring vaccine immunogenicity?
Hemagglutination inhibition assay
Western blotting
Mass spectrometry
PCR amplification
Explanation - HI assay is used for influenza vaccine potency by measuring antibody inhibition of virus-induced agglutination.
Correct answer is: Hemagglutination inhibition assay
Q.110 Which of the following best describes the 'WHO prequalification' process for vaccines?
It guarantees the vaccine is the cheapest option
It confirms the vaccine meets international quality and safety standards
It approves the vaccine for use only in high-income countries
It sets a global price for the vaccine
Explanation - WHO prequalification ensures vaccines meet global standards before procurement by UN agencies.
Correct answer is: It confirms the vaccine meets international quality and safety standards
Q.111 Which of the following is a typical purpose of 'adjuvants' in a subunit vaccine?
To increase the antigen's immunogenicity
To act as a preservative
To eliminate the need for a buffer
To reduce the manufacturing cost
Explanation - Adjuvants enhance the immune response to otherwise weak antigens in subunit vaccines.
Correct answer is: To increase the antigen's immunogenicity
Q.112 Which of the following is a key factor in selecting an 'antigen' for a vaccine?
Its color
Its ability to elicit a protective immune response
The cost of the antigen
The number of vials required
Explanation - The antigen must be immunogenic and safe to provoke protective immunity.
Correct answer is: Its ability to elicit a protective immune response
Q.113 Which of the following is a common method to test the stability of a vaccine during storage?
Accelerated degradation testing at elevated temperature
Counting the number of vials
Measuring the color intensity
Determining the price per dose
Explanation - Stability studies expose the vaccine to higher temperatures to predict shelf-life under normal conditions.
Correct answer is: Accelerated degradation testing at elevated temperature
Q.114 Which of the following best describes a 'mRNA vaccine'?
A vaccine that uses inactivated virus particles
A vaccine that contains viral DNA
A vaccine that delivers messenger RNA encoding the antigen
A vaccine that uses a live attenuated virus
Explanation - mRNA vaccines introduce genetic instructions for host cells to produce the antigenic protein.
Correct answer is: A vaccine that delivers messenger RNA encoding the antigen
Q.115 Which of the following is a typical safety assessment performed in a Phase I clinical trial?
Efficacy in a large population
Safety and tolerability in a small group of healthy volunteers
Long-term surveillance of vaccine recipients
Regulatory approval
Explanation - Phase I trials primarily assess safety and dosage tolerability.
Correct answer is: Safety and tolerability in a small group of healthy volunteers
Q.116 Which of the following best explains the importance of 'sterility assurance level' (SAL) in vaccine manufacturing?
It indicates the maximum allowable temperature during storage
It reflects the probability that a product contains no viable microorganisms
It determines the vaccine's shelf life
It sets the vaccine's potency level
Explanation - SAL ensures the vaccine is free from living contaminants that could cause infection.
Correct answer is: It reflects the probability that a product contains no viable microorganisms
Q.117 Which of the following is an advantage of using a 'viral vector' in vaccine delivery?
It eliminates the need for a host cell culture system
It can produce high levels of antigen in a short time
It requires no purification steps
It can be stored at room temperature indefinitely
Explanation - Viral vectors efficiently deliver genes to host cells, enabling rapid antigen expression.
Correct answer is: It can produce high levels of antigen in a short time
Q.118 Which of the following best describes the role of 'in vitro potency assays' for a live attenuated vaccine?
Measure the vaccine's color
Determine the number of viable cells in the vaccine
Assess the antigenic activity of the vaccine
Evaluate the vaccine's shelf life
Explanation - Potency assays confirm that each dose contains sufficient live attenuated organisms to elicit immunity.
Correct answer is: Assess the antigenic activity of the vaccine
Q.119 Which of the following best explains 'antibody-dependent cellular cytotoxicity' (ADCC) in vaccine immunity?
Antibodies directly killing infected cells
Antibodies facilitating phagocytosis of the pathogen
Antibody-mediated recruitment of natural killer cells to kill infected cells
Antibody-mediated neutralization of toxins
Explanation - ADCC involves antibody-coated infected cells being targeted by NK cells, leading to cytotoxicity.
Correct answer is: Antibody-mediated recruitment of natural killer cells to kill infected cells
Q.120 Which of the following is a common component of a vaccine's 'buffer system'?
Sodium chloride
Aluminum hydroxide
Polyethylene glycol
Sodium phosphate
Explanation - Sodium phosphate is used as a buffering agent to maintain pH stability in many vaccine formulations.
Correct answer is: Sodium phosphate
Q.121 Which of the following best describes a 'mosaic' vaccine strategy?
A vaccine that uses a single antigen from a virus
A vaccine that combines multiple antigenic variants from diverse strains
A vaccine that mimics a mosaic pattern on the vial surface
A vaccine that is delivered via a mosaic of routes
Explanation - Mosaic vaccines include a mix of epitopes from various strains to broaden protective coverage.
Correct answer is: A vaccine that combines multiple antigenic variants from diverse strains
Q.122 Which of the following is a typical role of a 'pharmacokinetic study' for a vaccine?
Measure how long a vaccine stays in the body and how it is processed
Determine the price of the vaccine
Analyze the vaccine’s color stability
Evaluate the vaccine’s packaging
Explanation - Pharmacokinetics assesses absorption, distribution, metabolism, and elimination of the vaccine components.
Correct answer is: Measure how long a vaccine stays in the body and how it is processed
Q.123 Which of the following best describes the term 'immunogenicity'?
The vaccine’s ability to produce a strong immune response
The vaccine’s stability at high temperatures
The vaccine’s cost to produce
The vaccine’s shelf life
Explanation - Immunogenicity refers to the capacity of a vaccine to stimulate an immune response.
Correct answer is: The vaccine’s ability to produce a strong immune response
Q.124 Which of the following best explains 'adjuvant' in the context of a vaccine?
A component that increases the vaccine’s potency by enhancing the immune response
A preservative that prevents spoilage
A stabilizer that maintains pH
An excipient that reduces cost
Explanation - Adjuvants boost the immunogenicity of antigens, especially in subunit vaccines.
Correct answer is: A component that increases the vaccine’s potency by enhancing the immune response
Q.125 Which of the following is a typical method for measuring the potency of an inactivated vaccine?
Plaque reduction neutralization assay
Hemagglutination inhibition assay
Western blot
PCR-based assay
Explanation - Plaque reduction tests measure the ability of antibodies to prevent viral infection in cell culture.
Correct answer is: Plaque reduction neutralization assay
Q.126 Which of the following is a key advantage of using an 'mRNA vaccine' during a pandemic?
It can be produced rapidly once the viral sequence is known
It requires no storage temperature
It does not need any adjuvant
It is more stable than all other vaccine types
Explanation - mRNA vaccine platforms allow quick design and synthesis, accelerating response to new pathogens.
Correct answer is: It can be produced rapidly once the viral sequence is known
Q.127 Which of the following is a common component of a 'live attenuated vaccine'?
Killed virus
Whole organism that can replicate but with reduced virulence
Subunit protein
DNA plasmid
Explanation - Live attenuated vaccines contain weakened organisms that can replicate, eliciting a strong immune response.
Correct answer is: Whole organism that can replicate but with reduced virulence
Q.128 Which of the following best describes the role of 'biological safety level' (BSL) in vaccine labs?
It sets the temperature for the cold chain
It dictates the level of containment needed for working with biological agents
It determines the vaccine cost
It specifies the packaging design
Explanation - BSL levels guide biosafety practices for handling infectious materials.
Correct answer is: It dictates the level of containment needed for working with biological agents
Q.129 Which of the following best explains a 'prime-boost' vaccination strategy?
A single dose given twice with no booster
Two doses of the same vaccine to enhance immunity
Administration of a vaccine followed by a placebo
A vaccine that does not require a booster dose
Explanation - Prime-boost strategies involve an initial dose (prime) and a subsequent dose (boost) to maximize the immune response.
Correct answer is: Two doses of the same vaccine to enhance immunity
Q.130 Which of the following is a primary safety assessment performed in preclinical studies?
Human efficacy trials
Animal toxicity studies
Market analysis
Pricing studies
Explanation - Preclinical safety involves testing the vaccine in animal models before human trials.
Correct answer is: Animal toxicity studies
Q.131 Which of the following best describes a 'mRNA vaccine'?
A vaccine that uses inactivated virus particles
A vaccine that contains genetic material encoding the antigen
A vaccine that uses a live attenuated organism
A vaccine that consists of purified proteins
Explanation - mRNA vaccines deliver messenger RNA that instructs host cells to produce the antigenic protein.
Correct answer is: A vaccine that contains genetic material encoding the antigen
Q.132 Which of the following best describes 'inactivated vaccine' production?
Culturing live viruses and then inactivating them
Using a killed or chemically treated pathogen
Purifying subunit proteins
Using DNA plasmids
Explanation - Inactivated vaccines are produced by growing viruses and then chemically or heat inactivating them.
Correct answer is: Culturing live viruses and then inactivating them
Q.133 Which of the following best explains the concept of 'antigenic drift'?
A virus losing its ability to infect cells
The accumulation of small genetic changes in a virus over time
The process of removing antigen from a vaccine
The reduction of a vaccine’s potency after storage
Explanation - Antigenic drift refers to minor mutations that can alter a virus’s antigenic profile.
Correct answer is: The accumulation of small genetic changes in a virus over time
Q.134 Which of the following is a common reason for a vaccine to undergo a Phase III clinical trial?
To evaluate vaccine safety in a small group of volunteers
To confirm efficacy in a large population and monitor large-scale safety
To determine the vaccine’s shelf life
To develop the manufacturing process
Explanation - Phase III trials are the largest trials to evaluate effectiveness and safety across diverse populations.
Correct answer is: To confirm efficacy in a large population and monitor large-scale safety