Immunization and Vaccine-Preventable Diseases Practice Questions

Q: Which vaccine is used to prevent cholera?

WC-rBS. ***WC-rBS*** * **WC-rBS** stands for **whole-cell, recombinant B subunit** vaccine, also known as **Dukoral**. * It is an **oral inactivated vaccine** containing killed *Vibrio cholerae* O1 bacteria and the recombinant B subunit of the cholera toxin, providing immunity against cholera. * **WC-rBS is the WHO-prequalified cholera vaccine** widely used in India and recommended for travellers and in epidemic settings. * It provides protection against both O1 and O139 serogroups and offers some cross-protection against ETEC (enterotoxigenic *E. coli*). *CVD 103-HgR* * **CVD 103-HgR** (commercially known as **Vaxchora**) is an **oral live-attenuated cholera vaccine** approved by the FDA. * It is a genetically modified *Vibrio cholerae* O1 Inaba strain with deleted cholera toxin genes. * While this is also a cholera vaccine, **it is primarily used in the United States** and is not the standard vaccine used in India or recommended by WHO for mass vaccination campaigns. * In the Indian context and for NEET-PG examinations, **WC-rBS (Dukoral) is the recognized cholera vaccine**. *Ty21a* * **Ty21a** is an **oral live-attenuated vaccine** used to prevent **typhoid fever**. * It is specifically designed to target *Salmonella Typhi* bacteria, not *Vibrio cholerae*. *None of the options* * This option is incorrect because WC-rBS is the well-established and WHO-recommended vaccine for the prevention of cholera in the Indian context.

Q: What is the standard amount of diphtheria toxoid in the DT vaccine?

30 Lf. ***30 Lf*** - The **DT vaccine** (pediatric diphtheria-tetanus vaccine) contains **30 Lf** of **diphtheria toxoid** per dose according to traditional formulations, along with tetanus toxoid. - This higher diphtheria toxoid content is standardized for vaccines administered to children younger than 7 years. - Note: Modern vaccine standards often express potency in **International Units (IU)** where ≥30 IU corresponds to approximately 15-25 Lf, though 30 Lf was the traditional specification. *5 Lf* - This reduced amount of diphtheria toxoid is present in adult formulations like **Tdap vaccine** and **Td vaccine** (typically 2-5 Lf). - The lower diphtheria toxoid content in adult vaccines is sufficient to maintain immunity in individuals with pre-existing immunity from childhood vaccination. *10 Lf* - This amount of diphtheria toxoid is not a standard specification for DT, Td, or Tdap vaccines. - Standard diphtheria toxoid amounts are typically 15-30 Lf for pediatric formulations (DT/DTP) and 2-5 Lf for adult formulations (Td, Tdap). *15 Lf* - While approximately 15 Lf may correspond to the minimum potency when measured in International Units (≥30 IU), the traditional standard specification for DT vaccine is **30 Lf**. - Vaccine formulations are precisely standardized to ensure optimal immunogenicity and safety.

Q: What are the serogroups covered by the bivalent meningococcal vaccine?

Serogroup A and C. ***Serogroup A and C*** - The **bivalent meningococcal vaccine** specifically targets and provides protection against **Neisseria meningitidis** serogroups **A and C**. - This vaccine is crucial for preventing invasive meningococcal disease caused by these prevalent strains, particularly in the African meningitis belt. - Examples include **meningococcal AC conjugate vaccines** used in mass vaccination campaigns. *Serogroup A* - While **Serogroup A** is one of the types covered by bivalent vaccines, it is not the only one. - A vaccine covering only Serogroup A would be a **monovalent vaccine**, not bivalent. *Serogroup W* - **Serogroup W** is covered by **quadrivalent meningococcal vaccines** (e.g., MenACWY) which protect against serogroups A, C, W, and Y. - It is **not included** in **bivalent** formulations. *Serogroup C* - While **Serogroup C** is one of the types covered by bivalent vaccines, it is not the only one. - A vaccine covering only Serogroup C would be a **monovalent vaccine**, not bivalent.

Q: Which live vaccine is contraindicated in AIDS patients?

BCG. **BCG** - The **BCG vaccine** is a live attenuated vaccine, and due to the immunocompromised state of AIDS patients, there is a significant risk of developing disseminated BCG infection. - This risk is particularly high in individuals with **severe immunodeficiency** (low CD4 count), making it a strong contraindication. *Oral Polio Vaccine (OPV)* - While OPV is a live vaccine, it is generally considered safe in asymptomatic HIV-infected individuals, but contraindicated in **symptomatic AIDS patients** due to the risk of vaccine-associated paralytic poliomyelitis [1]. - However, in many regions, the inactivated polio vaccine (IPV) is preferred for all HIV-infected individuals to completely eliminate this risk. *Varicella (Chickenpox)* - The **varicella vaccine** is a live attenuated vaccine; however, it is generally recommended for HIV-infected children and adults who are not severely immunocompromised (CD4 count >200 cells/µL). - The benefits of preventing severe chickenpox often outweigh the risks of vaccination in these individuals. *Measles* - The **measles vaccine (MMR)** is a live attenuated vaccine and is generally recommended for HIV-infected individuals who are not severely immunocompromised (CD4 count >200 cells/µL). - The severe morbidity and mortality associated with measles in immunocompromised individuals prioritize vaccination when appropriate.

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

Human Papillomavirus (HPV). ***Human Papillomavirus (HPV)*** - **HPV vaccine is NOT part of India's routine Universal Immunization Programme (UIP)**, making it the correct answer. - While **pilot programs** have been conducted in some states and various bodies recommend it, HPV has **never been universally included** in India's national immunization schedule. *TT (Tetanus Toxoid)* - **TT is a core component** of India's UIP and is actively used in immunization programs. - Given to **pregnant women** (2 doses during pregnancy) and as **Td vaccine** at 10 and 16 years of age. *OPV (Oral Polio Vaccine)* - While **OPV was phased out** from India's UIP in 2016, it was **historically part** of the national schedule. - India switched to **Injectable Polio Vaccine (IPV)** to eliminate vaccine-derived polio risk, but OPV was previously included. *Measles* - **Measles vaccine is actively included** in India's UIP as part of the **MR (Measles-Rubella) vaccine**. - Administered at **9 months and 16-24 months** of age as part of routine immunization.

Q: Which of the following diseases currently lacks a widely available effective vaccine?

Dengue fever. ***Dengue fever*** - While there is a vaccine (Dengvaxia) available in some regions for specific populations, its use is restricted due to concerns about increased risk of severe dengue in **seronegative individuals**. - There is currently **no single, universally recommended, and widely available effective vaccine** for all populations against all serotypes of dengue, making dengue a disease greatly in need of better vaccination strategies. *Yellow fever* - A **highly effective and safe live-attenuated vaccine** against yellow fever has been available for many decades, providing long-lasting immunity. - It is a standard vaccine for travelers to endemic areas and part of routine immunization programs in many affected countries. *Japanese encephalitis* - Several effective vaccines against Japanese encephalitis are **widely available and recommended** for individuals living in or traveling to endemic regions. - These vaccines include inactivated and live-attenuated forms, offering significant protection against the disease. *Russian spring summer encephalitis* - An **effective inactivated vaccine** is available for Russian spring-summer encephalitis and is recommended for those at risk due to occupational exposure or travel to endemic areas. - Vaccination provides reliable protection against this tick-borne viral infection.

Q: Oral cholera vaccine is effective for:

3 years. ***3 years*** - **Oral cholera vaccines** like Shanchol and Euvichol-Plus provide protection for at least **3 years** after complete 2-dose immunization. - Studies in endemic areas demonstrate sustained protection extending **up to 5 years** with Shanchol. - The **WHO recommends** OCVs as part of comprehensive cholera control strategies in endemic regions and outbreak settings. - This duration is based on field effectiveness studies and clinical trials in various populations. *2 years* - While **Dukoral** (another OCV) provides protection for approximately **2 years**, this is not the standard duration for the most widely used OCVs. - **2 years** represents the conservative lower estimate, not the established duration for Shanchol/Euvichol vaccines. - Current evidence supports longer protection than 2 years for most recipients. *12 months* - **12 months** significantly underestimates the protective duration of oral cholera vaccines. - All WHO-prequalified OCVs provide protection well beyond 1 year. - This duration might represent only the initial phase of immunity, not the full protective window. *6 months* - **6 months** is far too short and does not reflect the established efficacy of any current oral cholera vaccine. - While seroconversion occurs within weeks, the protective immunity lasts much longer. - No WHO-prequalified OCV has such a limited duration of protection.

Q: Which of the following vaccines is not included in the Mission Indradhanush program?

Typhoid fever vaccine. ***Typhoid fever vaccine*** - The **typhoid conjugate vaccine (TCV)** was introduced into India's Universal Immunization Programme in a phased manner starting from 2017-2018, but it is **not part of the core Mission Indradhanush vaccines** launched in 2014. - Mission Indradhanush primarily focuses on the original set of vaccines for common, preventable childhood diseases (BCG, DPT, OPV, Hepatitis B, Measles, etc.), and later additions like Rotavirus and PCV. - TCV rollout has been **state-specific and phased**, unlike the universal coverage of core Mission Indradhanush vaccines. *Diphtheria* - The **diphtheria vaccine** is a core component of the Mission Indradhanush program, aiming to protect children against this serious bacterial infection. - It is administered as part of the **DPT (Diphtheria, Pertussis, Tetanus)** or **Pentavalent vaccine** (DPT + Hib + Hepatitis B). *Polio* - The **polio vaccine** is a primary target of Mission Indradhanush, as India has maintained its polio-free status since 2014. - It is given as **OPV (Oral Polio Vaccine)** and/or **IPV (Inactivated Polio Vaccine)** to prevent poliomyelitis. *Tetanus* - The **tetanus vaccine** is included in the Mission Indradhanush program, administered with diphtheria and pertussis as the **DPT vaccine** or as part of the **Pentavalent vaccine**. - It protects against **tetanus**, a severe bacterial infection causing painful muscle spasms and lockjaw.

Q: WHO immunization evaluation coverage survey is normally done in what age group?

12-23 months. ***12-23 months*** - The **WHO immunization coverage survey** focuses on children aged **12-23 months** to ensure that they have completed their primary vaccination series, including doses that are typically given before 12 months of age but are evaluated after that period. - This age group allows for assessment of timely completion of vaccines like **measles (MCV1)** and the third dose of **DTP (DTP3)**, which are crucial indicators of a functioning immunization program. *0-12 months* - This age group is typically undergoing initial vaccinations, but evaluating coverage at this point might miss children who are still completing their scheduled doses. - Surveying this group wouldn't provide a complete picture of children who have received all recommended vaccines by their first birthday. *6-12 months* - Similar to 0-12 months, children in this age range are often in the process of receiving their primary vaccine series (e.g., DTP3 given around 6 months). - A survey at this stage would not fully capture the completion rates of all routine vaccinations due by the first birthday. *9-12 months* - While the first dose of measles vaccine (MCV1) is often given around 9 months, evaluating coverage only within this narrow window might not reflect the overall completion of the full primary immunization schedule. - It would miss children who might receive MCV1 at 12 months or later, and also wouldn't fully assess other vaccines given earlier.

Question 1

Which vaccine is used to prevent cholera?

Accepted Answer

WC-rBS

Answer

CVD 103-HgR

Answer

Ty21 A

Answer

None of the options

Question 2

What is the standard amount of diphtheria toxoid in the DT vaccine?

Accepted Answer

30 Lf

Answer

5 Lf

Answer

10 Lf

Answer

15 Lf

Question 3

What are the serogroups covered by the bivalent meningococcal vaccine?

Accepted Answer

Serogroup A and C

Answer

Serogroup A

Answer

Serogroup W

Answer

Serogroup C

Question 4

Which live vaccine is contraindicated in AIDS patients?

Accepted Answer

BCG

Answer

Measles

Answer

Varicella (Chickenpox)

Answer

Oral Polio Vaccine (OPV)

Question 5

What is the purpose of 'ring vaccination' in disease control?

Accepted Answer

Vaccination administered within a specific radius around a confirmed case.

Answer

A strategy to create lesions for disease identification.

Answer

Vaccination given to all individuals in a one-mile radius of a case.

Answer

A mass vaccination campaign targeting the entire population of a region.

Question 6

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

Accepted Answer

Human Papillomavirus (HPV)

Answer

TT

Answer

OPV

Answer

Measles

Question 7

Which of the following diseases currently lacks a widely available effective vaccine?

Accepted Answer

Dengue fever

Answer

Japanese encephalitis

Answer

Russian spring summer encephalitis

Answer

Yellow fever

Question 8

Oral cholera vaccine is effective for:

Accepted Answer

3 years

Answer

6 months

Answer

12 months

Answer

2 years

Question 9

Which of the following vaccines is not included in the Mission Indradhanush program?

Accepted Answer

Typhoid fever vaccine

Answer

Diphtheria

Answer

Polio

Answer

Tetanus

Question 10

WHO immunization evaluation coverage survey is normally done in what age group?

Accepted Answer

12-23 months

Answer

0-12 months

Answer

6-12 months

Answer

9-12 months

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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