Vaccine and Vaccination Practice Questions

Q: In which of the following conditions is the 23-serotype pneumococcal vaccine most useful?

Sickle cell anaemia. ***Sickle cell anaemia*** - Patients with **sickle cell anaemia** are highly susceptible to **encapsulated bacterial infections**, particularly _Streptococcus pneumoniae_, due to functional **asplenia** [1]. - The **23-serotype pneumococcal vaccine (PPSV23)** provides protection against a broad range of pneumococcal serotypes, crucial for preventing severe infections in this vulnerable population. *Child less than 2 years* - Children under 2 years typically receive the **pneumococcal conjugate vaccine (PCV13 or PCV15)**, which elicits a T-cell-dependent immune response, rather than the PPSV23. - **PPSV23** is a polysaccharide vaccine and is **less immunogenic** in very young children due to their immature immune systems. *Recurrent otitis media & sinusitis* - While pneumococcal infections can cause these conditions, the **conjugated pneumococcal vaccines (PCV13/15)** are generally preferred for preventing recurrent infections in children, targeting common causative serotypes. - The benefit of PPSV23 is more pronounced in **immunocompromised individuals** or those with specific high-risk conditions. *Cystic fibrosis* - Individuals with **cystic fibrosis** are at increased risk for respiratory infections, but primarily from organisms like **_Pseudomonas aeruginosa_** and **_Staphylococcus aureus_**, rather than solely _Streptococcus pneumoniae_. - While pneumococcal vaccination is recommended, their primary risk for severe disease isn't exclusively tied to pneumococcal disease to the same extent as persons with functional asplenia.

Q: Which of the following are the core components present in all acellular pertussis vaccines?

Pertactin, pertussis toxin, filamentous hemagglutinin. ***Correct: Pertactin, pertussis toxin, filamentous hemagglutinin*** - The **acellular pertussis vaccine (DTaP/Tdap)** contains purified components of *Bordetella pertussis* to elicit immunity without causing disease - The **three core components** present in ALL acellular pertussis vaccine formulations are: - **Pertussis toxoid (PT)** - inactivated pertussis toxin, critical for neutralizing the main virulence factor - **Filamentous hemagglutinin (FHA)** - adhesion protein essential for bacterial attachment - **Pertactin (PRN)** - outer membrane protein important for adhesion and immune response - These components are immunogenic and necessary for protective immunity while minimizing adverse reactions *Incorrect: Pertactin, filamentous hemagglutinin, cytotoxin, endotoxin* - While **pertactin** and **filamentous hemagglutinin** are correct, "cytotoxin" is too vague (likely refers to pertussis toxin which should be named specifically) - **Endotoxin** (lipopolysaccharide) is intentionally excluded from acellular vaccines due to its high reactogenicity and pro-inflammatory effects *Incorrect: Pertactin, filamentous hemagglutinin, fimbriae, endotoxin* - **Pertactin** and **filamentous hemagglutinin** are correct core components - While **fimbriae (types 2 and 3)** are included in some vaccine formulations (3-component vs 5-component vaccines), they are not present in ALL formulations - **Endotoxin** is excluded due to reactogenicity *Incorrect: Filamentous hemagglutinin, pertussis toxin, fimbriae, pertactin* - This option includes all three core components correctly - However, **fimbriae** are additional components in some enhanced formulations (5-component vaccines) but not universally present in all acellular pertussis vaccines (3-component vaccines contain only PT, FHA, and PRN) - Since the question asks for components in ALL vaccines, fimbriae cannot be included

Q: Neurological complications following rabies vaccine are common with

Semple Vaccine. ***Semple Vaccine*** - The **Semple vaccine (nerve tissue vaccine)** is associated with a higher incidence of **neurological complications** due to sensitisation to neural tissue components. - These complications can include **demyelinating encephalomyelitis** and paralysis, making it a less safe option compared to modern vaccines. *HDCS Vaccine* - The **Human Diploid Cell Vaccine (HDCV)** is a modern, highly purified rabies vaccine with a significantly **lower risk of neurological complications**. - It is considered one of the **safest and most effective** rabies vaccines available, rarely causing severe adverse events. *Chick embryo Vaccine* - **Chick embryo vaccines (CEV)** are produced in avian embryos and generally have a **low incidence of neurological complications** compared to nerve tissue vaccines. - While safer than older formulations, they are typically less used now than cell culture vaccines. *Duck Egg Vaccine* - **Duck embryo vaccines (DEV)** were an improvement over nerve tissue vaccines, offering a **reduced risk of neurological side effects**. - However, they still carried a slightly higher risk of adverse reactions compared to modern cell culture-derived vaccines.

Q: Adjuvants given along with antigens are going to

increase antigenicity. ***increase antigenicity*** - Adjuvants are substances added to vaccines to **enhance the immune response** to the co-administered antigen. - They work by various mechanisms, such as forming an antigen depot, activating antigen-presenting cells, and stimulating cytokine production, all leading to a **stronger and more prolonged immune response**. *reduce the antigenicity* - This statement is incorrect as adjuvants are specifically designed to **potentiate, not diminish**, the immune response to an antigen. - Reducing antigenicity would counteract the primary purpose of vaccination, which is to induce protective immunity. *reduce the toxigenicity* - Adjuvants generally do not directly impact the **toxigenicity** of an antigen, which refers to its ability to produce toxins. - While some vaccines detoxify bacterial toxins (e.g., toxoids), this is a separate process from the action of adjuvants that boost immune recognition. *increase toxigenicity* - This is incorrect; adjuvants are not intended to make an antigen more toxic. - Their role is to enhance immunogenicity safely, and increasing toxicity would be counterproductive and harmful.

Q: Conjugate vaccines are available for the prevention of invasive disease caused by all of the following except

N. Meningitidis (group B). ***N. Meningitidis (group B)*** - While conjugate vaccines are available for several serogroups of *N. meningitidis*, a **polysaccharide-protein conjugate vaccine** for **serogroup B** has been challenging to develop due to its **less immunogenic capsule** and antigenic mimicry with human tissues. - Currently, available vaccines against **meningococcal serogroup B** are **recombinant protein-based vaccines** (e.g., Bexsero, Trumenba), not traditional polysaccharide-protein conjugate vaccines. *Strep pneumoniae* - **Pneumococcal conjugate vaccines (PCVs)**, such as PCV13 and PCV15, effectively prevent invasive disease caused by *Streptococcus pneumoniae* in both children and adults. - These vaccines conjugate **polysaccharide capsular antigens** to carrier proteins, enhancing immunogenicity, especially in young children. *H influenzae* - The **Haemophilus influenzae type b (Hib) conjugate vaccine** is highly effective in preventing invasive Hib disease, including meningitis and epiglottitis. - This vaccine links the **Hib polysaccharide capsule** to a protein carrier, eliciting a T-cell-dependent immune response. *N. Meningitidis (group C)* - **Meningococcal conjugate vaccines** are widely available and routinely used to prevent invasive disease caused by *Neisseria meningitidis* serogroup C. - These vaccines include **monovalent (e.g., MenC)** and **quadrivalent (e.g., MenACWY)** formulations that target serogroup C.

Q: The following vaccine is developed against cholera -

Dukoral. ***Dukoral*** - **Dukoral** is an **oral cholera vaccine** that contains inactivated *Vibrio cholerae* O1 and O139 bacteria and recombinant B subunit of cholera toxin, providing protection against cholera. - It is often recommended for travelers visiting areas where **cholera** is endemic. *Ty 21a oral* - **Ty21a oral** is an **attenuated live oral vaccine** used for the prevention of **typhoid fever**, caused by *Salmonella Typhi*. - It does not offer protection against cholera. *Rotavirus vaccine* - **Rotavirus vaccine** is an **oral vaccine** used to prevent severe **rotavirus gastroenteritis** in infants and young children. - While it protects against diarrheal disease, it is not effective against cholera, which is caused by *Vibrio cholerae*. *Vi polysaccharide* - **Vi polysaccharide vaccine** is an **injectable vaccine** used for the prevention of **typhoid fever**, targeting the Vi capsular polysaccharide of *Salmonella Typhi*. - Similar to Ty21a, it is effective against typhoid but not cholera.

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

Salk vaccine. ***Salk vaccine*** - The **Salk vaccine** is an **inactivated (killed)** polio vaccine (IPV), meaning it does not contain live virus. - Inactivated vaccines use killed or inactive forms of pathogens to trigger an immune response without causing disease. *BCG vaccine* - The **BCG (Bacillus Calmette-Guérin) vaccine** is a **live-attenuated vaccine** used to prevent tuberculosis. - Live-attenuated vaccines contain a weakened form of the pathogen, which can replicate but typically doesn't cause disease in healthy individuals. *Measles vaccine* - The **measles vaccine** (often part of the MMR vaccine) is a **live-attenuated vaccine**. - It contains a weakened live measles virus to stimulate a strong, long-lasting immune response. *Yellow fever vaccine* - The **yellow fever vaccine** is a **live-attenuated vaccine** prepared from a weakened strain of the yellow fever virus. - It provides highly effective and long-lasting protection against yellow fever.

Q: Which of the following components is specifically used to enhance the antigenicity of a vaccine?

Adjuvant. ***Adjuvant*** - An **adjuvant** is a substance added to a vaccine to enhance the **immune response** to the antigen without having any specific antigenic properties itself. - They work by various mechanisms, such as forming a **depot** for the antigen, stimulating antigen-presenting cells, or activating innate immune pathways. *Preservative* - A **preservative** is included in some vaccines to prevent **microbial growth** and contamination, especially in multi-dose vials. - It does not enhance the immune response to the antigen. *Stabilizer* - A **stabilizer** helps maintain the **integrity** and **potency** of the vaccine's active ingredients over time and under varying storage conditions. - It prevents degradation of the antigen but does not directly boost its immunogenicity. *None of the options* - This option is incorrect because **adjuvants** are specifically designed and used to enhance the antigenicity of a vaccine. - The other listed components serve different purposes within a vaccine formulation.

Q: Which vaccine requires annual updates due to frequent antigenic changes?

Influenza. ***Influenza*** - The influenza virus undergoes frequent **antigenic drift** and **antigenic shift**, which are changes in its surface proteins (hemagglutinin and neuraminidase). - These constant changes necessitate annual updates to the influenza vaccine to match the circulating strains predicted for the upcoming flu season. *Measles* - The measles virus is **antigenically stable**, meaning it does not frequently change its surface proteins. - Due to its stability, a highly effective and long-lasting vaccine can be produced, and annual updates are not required. *Rubella* - The rubella virus is also **antigenically stable**, similar to measles. - A single vaccine, usually given as part of the MMR (Measles, Mumps, Rubella) vaccine, provides long-term immunity without the need for annual revision. *BCG* - The Bacillus Calmette-Guérin (BCG) vaccine targets *Mycobacterium tuberculosis* and is not subject to frequent antigenic changes. - It is a live-attenuated vaccine that provides long-lasting immunity, and annual boosters or updates are not necessary.

Q: Pneumococcal vaccine PPSV23 (23-valent polysaccharide) has shown the best results in the following people:

Sickle cell anemia. ***Sickle cell anemia*** - Patients with **sickle cell anemia** are at very high risk for **invasive pneumococcal disease** due to functional asplenia, making vaccination critical. - The **polysaccharide vaccine (PPSV23)** is recommended for individuals aged 2 years and older with chronic medical conditions like sickle cell disease as it elicits a T-cell-independent immune response. *Cystic fibrosis* - While individuals with **cystic fibrosis** are at increased risk for respiratory infections, the primary pathogens are typically *P. aeruginosa* and *S. aureus*, not *S. pneumoniae*. - Although pneumococcal vaccination is recommended for these patients, it does not show the "best results" in terms of reducing overall infection burden compared to those with **functional asplenia**. *Child less than 2 year age* - Children under **2 years of age** have an immature immune system that responds poorly to **polysaccharide vaccines** (like PPSV23) because they cannot mount a T-cell-independent response effectively. - The **conjugate vaccine (PCV13)**, which elicits a T-cell-dependent response, is therefore recommended for this age group. *Recurrent otitis media and sinusitis* - While *S. pneumoniae* is a common cause of **otitis media** and **sinusitis**, these conditions are typically non-invasive, and vaccination is a general recommendation rather than showing the "best results" in preventing severe, life-threatening outcomes. - The impact of **pneumococcal vaccination** in preventing recurrent otitis media and sinusitis in otherwise healthy individuals does not compare to its life-saving efficacy in immunosuppressed or asplenic patients.

Question 1

In which of the following conditions is the 23-serotype pneumococcal vaccine most useful?

Accepted Answer

Sickle cell anaemia

Answer

Child less than 2 years

Answer

Recurrent otitis media & sinusitis

Answer

Cystic fibrosis

Question 2

Which of the following are the core components present in all acellular pertussis vaccines?

Accepted Answer

Pertactin, pertussis toxin, filamentous hemagglutinin

Answer

Pertactin, filamentous hemagglutinin, cytotoxin, endotoxin

Answer

Pertactin, filamentous hemagglutinin, fimbriae, endotoxin

Answer

Filamentous hemagglutinin, pertussis toxin, fimbriae, pertactin

Question 3

Neurological complications following rabies vaccine are common with

Accepted Answer

Semple Vaccine

Answer

HDCS Vaccine

Answer

Chick embryo Vaccine

Answer

Duck Egg Vaccine

Question 4

Adjuvants given along with antigens are going to

Accepted Answer

increase antigenicity

Answer

reduce the antigenicity

Answer

reduce the toxigenicity

Answer

increase toxigenicity

Question 5

Conjugate vaccines are available for the prevention of invasive disease caused by all of the following except

Accepted Answer

N. Meningitidis (group B)

Answer

Strep pneumoniae

Answer

H influenzae

Answer

N. Meningitidis (group C)

Question 6

The following vaccine is developed against cholera -

Accepted Answer

Dukoral

Answer

Ty 21a oral

Answer

Rotavirus vaccine

Answer

Vi polysaccharide

Question 7

Which of the following is NOT a live vaccine?

Accepted Answer

Salk vaccine

Answer

BCG vaccine

Answer

Measles vaccine

Answer

Yellow fever vaccine

Question 8

Which of the following components is specifically used to enhance the antigenicity of a vaccine?

Accepted Answer

Adjuvant

Answer

Preservative

Answer

Stabilizer

Answer

None of the options

Question 9

Which vaccine requires annual updates due to frequent antigenic changes?

Accepted Answer

Influenza

Answer

Measles

Answer

Rubella

Answer

BCG

Question 10

Pneumococcal vaccine PPSV23 (23-valent polysaccharide) has shown the best results in the following people:

Accepted Answer

Sickle cell anemia

Answer

Cystic fibrosis

Answer

Recurrent otitis media and sinusitis

Answer

Child less than 2 years of age

Vaccine and Vaccination — MCQs

Vaccine and Vaccination — MCQs

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