Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases Indian Medical PG Practice Questions and MCQs

Question 451: Which vaccine is recommended to be given every year?

A. Hepatitis A vaccine
B. Varicella (Chickenpox) vaccine
C. Influenza vaccine (Correct Answer)
D. Hepatitis B vaccine

Explanation: ***Influenza vaccine*** - The **influenza virus** constantly mutates, leading to new strains emerging each year. - Annual vaccination is recommended to provide protection against the most prevalent strains predicted for the upcoming flu season. - This is the only vaccine that requires yearly administration due to **antigenic drift**. *Hepatitis A vaccine* - The Hepatitis A vaccine provides **long-term immunity** after a two-dose series. - It does not require annual administration after the initial series is completed. *Varicella (Chickenpox) vaccine* - The Varicella vaccine (typically a two-dose series) offers **durable immunity** against chickenpox. - Annual vaccination is not necessary as protection typically lasts for many years. *Hepatitis B vaccine* - The Hepatitis B vaccine series (usually three doses) provides **long-lasting protection** against the Hepatitis B virus. - Routine annual boosters are not required for individuals who have completed the primary series.

Question 452: Which vaccine is not included in the Indradhanush mission across all states?

A. Tuberculosis
B. Measles
C. Diphtheria
D. Japanese Encephalitis (Correct Answer)

Explanation: ***Japanese Encephalitis*** - The **Japanese Encephalitis (JE) vaccine** is not universally included in the Indradhanush mission across all states; its inclusion is **state-specific** and targeted to districts with high JE prevalence. - While other core vaccines are administered nationwide to increase full immunization coverage, the JE vaccine's use is tailored to **endemic regions**. *Tuberculosis* - The **BCG vaccine** for **tuberculosis (TB)** is a fundamental part of India's Universal Immunization Program and is routinely administered under the Indradhanush mission across all states. - It provides protection against severe forms of TB, particularly in infants and young children. *Measles* - The **Measles vaccine** (often combined with Rubella as MMR) is a critical component of the Indradhanush mission, ensuring widespread protection against this highly contagious disease. - High coverage rates for measles vaccination are essential for achieving **herd immunity** and reducing child mortality. *Diphtheria* - The **Diphtheria vaccine** (usually given as part of DPT/DTaP/Tdap) is a core vaccine under the Indradhanush mission, universally available across all states. - It targets a severe bacterial infection that can cause breathing difficulties, heart problems, and nerve damage.

Question 453: Which of the following statements about the MR vaccination campaign launched by WHO is false?

A. The MR campaign is a one-time campaign and it is followed up by routine immunization
B. Congenital rubella syndrome (CRS) is responsible for irreversible birth defects.
C. Children from 9 months to less than 15 years are vaccinated.
D. India has not yet launched this campaign. (Correct Answer)

Explanation: ***India has not yet launched this campaign.*** - This statement is **false** because India has actively participated in the **MR vaccination campaign**, reaching millions of children. - The campaign is a key component of India's efforts to eliminate measles and control rubella. *Children from 9 months to less than 15 years are vaccinated.* - This statement is **true** because the age group for the MR vaccination campaign is typically **9 months to 15 years**, aiming to provide widespread immunity. - This age range targets both infants susceptible to measles and older children who may not have received previous vaccinations. *Congenital rubella syndrome (CRS) is responsible for irreversible birth defects.* - This statement is **true** as **Congenital Rubella Syndrome (CRS)** can lead to severe and **irreversible birth defects**, including heart anomalies, deafness, and cataracts, if a pregnant woman contracts rubella. - The MR vaccine protects against rubella, thereby preventing CRS in future generations. *The MR campaign is a one-time campaign and it is followed up by routine immunization* - This statement is **true** because the **MR campaign** is typically a large-scale, one-time catch-up initiative aimed at quickly boosting immunity in a population. - After the campaign, **routine immunization programs** continue to administer MR vaccine doses to ensure sustained protection against measles and rubella in newborns.

Question 454: Japanese encephalitis vaccine in routine schedule is given in how many doses -

A. Two doses (at 9-12 months and 15-18 months) (Correct Answer)
B. Single dose vaccine
C. Three doses 1 month apart followed by a booster if needed
D. Three doses with the second dose 1 month and 3rd dose 6 months after the first dose

Explanation: ***Two doses (at 9-12 months and 15-18 months)*** - The **routine JE vaccination schedule in India** as per NTAGI and IAP recommendations involves **two doses**. - **First dose** is given at **9-12 months** of age. - **Second dose** is administered at **15-18 months** (or up to 24 months), approximately **6-12 months after the first dose**. - This provides adequate long-term protection against Japanese encephalitis in endemic areas. *Single dose vaccine* - A single dose does **not provide adequate long-lasting protection** against Japanese encephalitis. - The **immune response** from a single dose is insufficient for routine immunization. - Two doses are required to ensure protective antibody levels. *Three doses 1 month apart followed by a booster if needed* - This schedule is **not part of the routine immunization program** for JE in India. - The standard routine schedule involves **only 2 primary doses**, not three. - Rapid three-dose schedules may be used in specific outbreak situations but not for routine immunization. *Three doses with the second dose 1 month and 3rd dose 6 months after the first dose* - This three-dose schedule is **not the routine JE vaccination schedule** in India. - This may be confused with schedules for other vaccines or older JE vaccine protocols. - The current **routine schedule requires only 2 doses** at specified age intervals.

Question 455: Which Diphtheria vaccine is recommended for a 14-year-old girl?

A. DT vaccine (Diphtheria, Tetanus)
B. No suitable vaccine
C. DPT vaccine (Diphtheria, Pertussis, Tetanus)
D. Tdap vaccine (Tetanus, Diphtheria, Pertussis) (Correct Answer)

Explanation: ***Tdap vaccine (Tetanus, Diphtheria, Pertussis)*** - For a **14-year-old adolescent**, the **Tdap vaccine** is an appropriate choice as it provides protection against tetanus, diphtheria, and pertussis with reduced antigen content suitable for this age group. - In **Indian practice**, the **Td vaccine** (tetanus-diphtheria, adult formulation) is more commonly recommended as per **IAP guidelines** for the 10-16 years age group, but **Tdap is equally acceptable** and provides additional pertussis protection. - The **adolescent booster dose** at 10-16 years is crucial as immunity from childhood vaccination wanes over time. - Among the given options, **Tdap is the most appropriate vaccine** for this 14-year-old girl. *DPT vaccine (Diphtheria, Pertussis, Tetanus)* - **DPT** refers to the **whole-cell pertussis vaccine** used in the **primary childhood series** (typically at 6, 10, and 14 weeks). - It is **not recommended for adolescents or adults** due to higher reactogenicity and increased side effects (local reactions, fever) from the whole-cell pertussis component. - The childhood formulation has higher antigen concentrations unsuitable for older age groups. *DT vaccine (Diphtheria, Tetanus)* - **DT vaccine** is the **pediatric formulation** (higher diphtheria antigen) used for children **under 7 years of age** who have contraindications to the pertussis component. - It is **not the standard choice for adolescents**, who require the adult formulation (Td/Tdap) with reduced diphtheria toxoid content to minimize adverse reactions. - It does not provide pertussis protection, which is important for adolescents to prevent transmission to vulnerable infants. *No suitable vaccine* - This is **incorrect** as specific vaccine formulations (Tdap/Td) are available and recommended for adolescents. - **Adolescent booster vaccination** is an essential component of the immunization schedule to maintain immunity against diphtheria, tetanus, and pertussis.

Question 456: Immunity starts after how many days of yellow fever vaccination ?

A. 7-10 days (Correct Answer)
B. 2-3 weeks
C. 4-5 weeks
D. 2-3 months

Explanation: ***Correct: 7-10 days*** - The **onset of immunity** after yellow fever vaccination typically occurs within **7-10 days** for most individuals. - This period is crucial for the body to develop a protective immune response, which is why travelers are advised to get vaccinated at least **10 days before potential exposure** as per WHO guidelines. - Approximately **95% of vaccinees** develop protective immunity by day 10. *Incorrect: 2-3 weeks* - While immunity continues to strengthen over this period, **initial protective immunity** is established earlier, typically by 7-10 days. - This option represents a slightly delayed timetable for the initial establishment of immunity. *Incorrect: 4-5 weeks* - This duration is significantly longer than the time required for the initial protective immunity to develop after yellow fever vaccination. - At this point, robust and **long-lasting immunity** would generally be established, but it's not when immunity "starts." *Incorrect: 2-3 months* - This timeframe is far too long for the *start* of immunity following yellow fever vaccination. - By this point, immunity is not only well-established but also **lifelong** (the vaccine provides protection for life after a single dose).

Question 457: Which vaccine is the most widely used globally in childhood vaccination programs, aside from the Oral Polio Vaccine (OPV)?

A. BCG vaccine
B. DPT vaccine (Correct Answer)
C. Influenza vaccine
D. Pneumococcal vaccine

Explanation: ***DPT vaccine*** - The **DPT (diphtheria, pertussis, and tetanus) vaccine** is the most widely used childhood vaccine globally after OPV, forming the backbone of the **WHO's Expanded Programme on Immunization (EPI)**. - It has **near-universal adoption** across countries worldwide with approximately **86% global coverage** and is administered as a **3-dose primary series** to all children, making it the standard benchmark for measuring immunization program performance. - Its widespread use reflects the global burden of these three bacterial diseases and the vaccine's proven efficacy in preventing severe outcomes and transmission. *BCG vaccine* - The **BCG (Bacillus Calmette-Guérin) vaccine** protects against **tuberculosis** and is widely used, particularly in countries with high TB prevalence. - However, its use is **not universal** – many countries with low TB incidence (such as the USA and several European nations) do not include BCG in routine childhood schedules, limiting its global "universality" compared to DPT. - BCG is typically given as a **single dose at birth**, whereas DPT requires multiple doses throughout infancy. *Influenza vaccine* - The **influenza vaccine** is recommended annually due to antigenic drift of the virus, but its global childhood vaccination coverage is significantly lower compared to standard EPI vaccines like DPT. - It is often prioritized for specific risk groups rather than universal immunization for all children in many parts of the world. *Pneumococcal vaccine* - The **pneumococcal vaccine** targets **Streptococcus pneumoniae**, a cause of pneumonia, meningitis, and other severe diseases. - While increasingly integrated into national immunization schedules, its global adoption (especially as of 2015) was still lower than DPT, with many low- and middle-income countries only recently introducing it.

Question 458: Which of the following statements about the Pneumococcal Polysaccharide Vaccine (PPV) is correct?

A. Administered at birth
B. Recommended for individuals with sickle cell disease (Correct Answer)
C. Widely used in the general population
D. Derived from live attenuated pneumococcal bacteria

Explanation: ***Recommended for individuals with sickle cell disease*** - Individuals with **sickle cell disease** are at significantly increased risk of severe and invasive **pneumococcal infections** due to **functional asplenia**. - The PPV is crucial for providing **prophylactic protection** against these life-threatening infections in this vulnerable population. *Administered at birth* - The **Pneumococcal Conjugate Vaccine (PCV)** is part of routine childhood immunizations and is administered at specific ages, but neither PCV nor PPV is given **at birth**. - **PCV** is typically given starting at **2 months of age**, while **PPV** is generally recommended for older children and adults at high risk. *Widely used in the general population* - The **Pneumococcal Conjugate Vaccine (PCV)** is widely used in the general *pediatric* population as part of routine immunization schedules. - The **Pneumococcal Polysaccharide Vaccine (PPV)** is primarily recommended for **adults 65 years and older** and individuals with certain **underlying medical conditions** or compromised immune systems, not the general population. *Derived from live attenuated pneumococcal bacteria* - The **PPV** is a **polysaccharide vaccine**, meaning it is composed of purified capsular polysaccharides from various serotypes of *Streptococcus pneumoniae*. - It is an **inactivated vaccine** and does not contain live attenuated bacteria; such a vaccine would be contraindicated in immunocompromised individuals.

Question 459: Which of the following statements regarding polio vaccination is false?

A. OPV induces both humoral and intestinal immunity
B. IPV is given intramuscularly
C. First OPV is given at 4 weeks (Correct Answer)
D. Both killed and live vaccines are available

Explanation: ***First OPV is given at 4 weeks*** - The first dose of **Oral Polio Vaccine (OPV)** is typically given at birth, often referred to as the **"zero dose,"** before the 4-week mark. - Subsequent doses are given at 6, 10, and 14 weeks of age as part of the routine immunization schedule, making the statement that the first OPV is given at 4 weeks false. *OPV induces both humoral and intestinal immunity* - **OPV** is a **live attenuated vaccine** that replicates in the gut, thereby stimulating both a systemic **humoral immune response** (producing antibodies in the bloodstream) and **local intestinal immunity** (IgA antibodies in the gut). - This **intestinal immunity** is crucial for preventing viral replication in the gut and reducing transmission. *IPV is given intramuscularly* - The **Inactivated Polio Vaccine (IPV)**, also known as the **Salk vaccine**, is administered via injection, specifically through the **intramuscular route**. - This method ensures systemic absorption and the development of **humoral immunity**. *Both killed and live vaccines are available* - There are two main types of polio vaccines: **Oral Polio Vaccine (OPV)**, which is a **live attenuated vaccine**, and **Inactivated Polio Vaccine (IPV)**, which is a **killed vaccine**. - Both types have been instrumental in polio eradication efforts, each with distinct advantages and disadvantages.

Question 460: Vaccine derived polio virus outbreaks are due to?

A. Type-2 poliovirus (Correct Answer)
B. Type-3 poliovirus
C. Type-1 poliovirus
D. All types of poliovirus

Explanation: ***Type-2 poliovirus*** - The **type 2 poliovirus (PV2)** component of the oral polio vaccine (OPV) has historically been associated with the majority of vaccine-derived poliovirus (VDPV) outbreaks. - The **attenuated PV2 strain** in OPV can revert to neurovirulent forms in rare cases, leading to outbreaks, especially in areas with low vaccination coverage. - Type 2 was responsible for **>90% of circulating VDPV (cVDPV) cases**, which led to the global switch from trivalent OPV to bivalent OPV (without type 2) in April 2016. *Type-3 poliovirus* - While **type 3 poliovirus (PV3)** was also part of OPV, **wild type 3 poliovirus was declared eradicated in 2019** (last case in 2012). - VDPV outbreaks due to PV3 are rare compared to PV2. *Type-1 poliovirus* - **Type 1 poliovirus (PV1)** is still endemic in some regions and causes wild poliovirus (WPV) infections. - Although PV1 is included in bivalent OPV, **VDPV outbreaks** from the PV1 component are very rare compared to PV2. *All types of poliovirus* - While all three serotypes of poliovirus were historically included in trivalent OPV, **PV2 is overwhelmingly responsible** for VDPV outbreaks. - **Wild type 2 poliovirus was eradicated in 2015** (last case 1999), but the vaccine strain continued to cause VDPV outbreaks until type 2 was removed from routine OPV.

Practice by Chapter

Principles of Immunization

Practice Questions

Types of Vaccines

Practice Questions

Universal Immunization Program

Practice Questions

Cold Chain System

Practice Questions

Vaccine Storage and Handling

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Adverse Events Following Immunization

Practice Questions

National Immunization Schedule

Practice Questions

Polio Eradication

Practice Questions

Measles Elimination

Practice Questions

Tetanus Control

Practice Questions

New and Underutilized Vaccines

Practice Questions

Vaccination Coverage Assessment

Practice Questions

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