Immunization and Vaccine-Preventable Diseases — MCQs

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

Question 391: Herd immunity is not important in

A. Pertussis
B. All of the options
C. Tetanus (Correct Answer)
D. Diphtheria

Explanation: ***Tetanus*** - **Tetanus** is caused by a toxin produced by *Clostridium tetani*, which is present in the environment (e.g., soil, manure) and enters the body through wounds. - Its transmission is **not person-to-person**, therefore, herd immunity, which relies on reducing transmission pathways within a population, does not apply to tetanus. *Pertussis* - **Pertussis (whooping cough)** is a highly contagious respiratory disease transmitted directly from person to person via respiratory droplets. - **Herd immunity** is crucial for protecting vulnerable populations (e.g., unvaccinated infants) from pertussis by reducing the overall circulation of the pathogen. *All of the options* - This option is incorrect because herd immunity is important for diseases like pertussis and diphtheria, where person-to-person transmission is the primary mode of spread. - Tetanus is the exception, as its transmission is environmental, not through person-to-person contact. *Diphtheria* - **Diphtheria** is a contagious bacterial infection that spreads from person to person through respiratory droplets. - **Herd immunity** plays a vital role in preventing outbreaks and protecting unvaccinated individuals, particularly children, from this severe infection.

Question 392: Two viral vaccines are expected to reduce the incidence of cancers. Which vaccines are these?

A. Measles virus and rubella virus vaccines
B. HAV and poliovirus vaccines
C. Adenovirus and mumps virus vaccines
D. HPV 16/18 and hepatitis B vaccines (Correct Answer)

Explanation: ***HPV 16/18 and hepatitis B vaccines*** - The **HPV vaccine** (targeting types 16 and 18) protects against human papillomavirus infections, which are the primary cause of cervical cancer and are also linked to other anogenital and oropharyngeal cancers. - The **Hepatitis B vaccine** prevents chronic hepatitis B infection, a major risk factor for hepatocellular carcinoma (liver cancer). *Measles virus and rubella virus vaccines* - The measles and rubella vaccines protect against highly contagious viral diseases but are **not directly associated** with cancer prevention. - While viral infections can sometimes contribute to cancer development indirectly (e.g., chronic inflammation), these specific vaccines do not prevent cancer. *HAV and poliovirus vaccines* - The HAV (Hepatitis A virus) vaccine prevents hepatitis A, which causes acute liver inflammation but **does not lead to chronic infection or liver cancer**. - The poliovirus vaccine prevents poliomyelitis, a neurological disease, and has no known direct link to cancer prevention. *Adenovirus and mumps virus vaccines* - Adenovirus vaccines target various respiratory and gastrointestinal infections and are not linked to cancer prevention. - The mumps virus vaccine protects against mumps, a parotitis-causing infection, and has **no established direct role** in reducing cancer incidence.

Question 393: In which of the following is immunization given after infection is started

A. Influenza
B. Rabies (Correct Answer)
C. Poliomyelitis
D. Herpes

Explanation: ***Rabies*** - Rabies vaccine is unique because it can be administered **post-exposure**, forming the basis of **post-exposure prophylaxis (PEP)**. - Due to the long incubation period of the rabies virus, PEP can be effective in preventing the disease even after exposure. *Influenza* - The influenza vaccine is given **before exposure** to prevent or lessen the severity of the flu. - It is an annual vaccine recommended for seasonal prevention and is not effective once an infection has started. *Poliomyelitis* - Polio vaccines (both inactivated and oral live-attenuated) are given **pre-exposure** to prevent infection. - They are part of routine childhood immunization schedules and are not used as treatment after infection begins. *Herpes* - There is no widely available preventative vaccine for common herpes simplex virus (HSV) infections. - Antiviral medications are used to manage outbreaks or prevent recurrence, not a post-exposure vaccine.

Question 394: Which of the following is used as prophylaxis in case of diphtheria:

A. DPT vaccine (Correct Answer)
B. Erythromycin
C. Ampicillin
D. DAT

Explanation: ***DPT vaccine*** - The **DPT vaccine** (Diphtheria, Pertussis, Tetanus) provides **active immunity** against diphtheria by introducing inactivated diphtheria toxin (toxoid). - This primes the immune system to produce antibodies, offering **long-term prophylaxis** against future infections. *Erythromycin* - **Erythromycin** is an antibiotic used for the **treatment** of diphtheria, not for primary prophylaxis. - It works by inhibiting bacterial protein synthesis, but does not induce protective antibodies for long-term prevention. *Ampicillin* - **Ampicillin** is a penicillin-class antibiotic that is generally **not the drug of choice** for either prophylaxis or treatment of diphtheria. - While it has broad-spectrum activity, diphtheria treatment typically relies on antitoxin and specific macrolide antibiotics like erythromycin. *DAT* - **DAT (Diphtheria Antitoxin)** provides **passive immunity** by directly administering preformed antibodies against diphtheria toxin, used for treating active diphtheria infections or as post-exposure prophylaxis in unimmunized individuals. - It offers immediate but **short-lived protection** and is not used for routine, long-term prophylaxis.

Question 395: The efficiency of cold chain system for oral polio vaccine as monitored by Vaccine Vial Monitor (VVM) depends on:

A. Viral potency test
B. Temperature indicator of the system
C. Change in the colour of vaccine
D. Change in colour of monitor (Correct Answer)

Explanation: ***Change in colour of monitor*** - The Vaccine Vial Monitor (VVM) is a label on vaccine vials that changes color progressively when exposed to heat, indicating cumulative heat exposure. - A change in the **VVM's color** signifies that the vaccine may have been exposed to temperatures that could reduce its potency and determines its usability. *Viral potency test* - A **viral potency test** directly measures the amount of live virus in a vaccine sample, which is a laboratory-based assessment and not a real-time field indicator of cold chain efficiency. - While it assesses the vaccine's actual effectiveness, it is not what the VVM monitors in the field for cold chain breaks. *Temperature indicator of the system* - A **temperature indicator** on the cold chain system itself monitors the temperature of the storage unit, not the cumulative heat exposure of individual vaccine vials. - While important for overall cold chain management, it doesn't directly indicate the heat exposure specific to a vaccine vial like a VVM does. *Change in the colour of vaccine* - A change in the **color of the vaccine** itself could indicate contamination or degradation due to various factors, not exclusively due to inadequate cold chain management as monitored by VVM. - The VVM is a separate label designed specifically to monitor heat exposure effects on the vaccine.

Question 396: All of the following are components of primordial prevention EXCEPT

A. Behavioural changes
B. Health education
C. Nutritional education
D. Immunization (Correct Answer)

Explanation: ***Immunization*** - **Immunization** is a component of **primary prevention**, aiming to prevent the onset of disease in healthy individuals. - Primordial prevention focuses on preventing the establishment of risk factors themselves, rather than preventing the disease directly. *Behavioural changes* - **Behavioural changes**, such as encouraging healthy lifestyles from a young age, are central to primordial prevention. - The goal is to prevent the adoption of unhealthy behaviours that could lead to disease later in life. *Health education* - **Health education**, particularly in early life stages, is a key strategy for primordial prevention. - It helps in fostering healthy habits and promoting awareness before risk factors emerge. *Nutritional education* - Providing **nutritional education** to prevent the development of poor dietary habits is a core aspect of primordial prevention. - This aims to prevent the establishment of risk factors like obesity and hypertension from an early age.

Question 397: National switch day for polio vaccine in India is

A. April 23, 2014
B. April 26, 2017
C. April 25, 2016 (Correct Answer)
D. April 24, 2025

Explanation: ***April 25, 2016*** - This date marks India's participation in the coordinated **global "switch day"** when 155 countries, including India, simultaneously transitioned from using **trivalent oral polio vaccine (tOPV)** to **bivalent oral polio vaccine (bOPV)**. - The switch was a critical step in the **polio eradication endgame strategy**, specifically targeting the withdrawal of the type 2 vaccine component due to the eradication of wild poliovirus type 2. - India successfully implemented this switch across all its immunization centers on this single day. *April 23, 2014* - This date does not correspond to the polio vaccine switch day in India. - While significant events occurred in polio eradication efforts around this time, the specific tOPV to bOPV switch was on April 25, 2016. *April 26, 2017* - This date is not the polio vaccine switch day in India. - By 2017, the tOPV-bOPV switch had already been successfully implemented globally and in India. *April 24, 2025* - This date is in the future and therefore cannot be the historical polio vaccine switch day. - There are no current plans for another vaccine switch of this magnitude for polio on this date.

Question 398: True about polioviruses is -

A. Spastic paralysis
B. Most cases are symptomatic
C. Historically, intramuscular injections during the incubation period were thought to increase paralysis risk.
D. Inactivated polio vaccine (IPV) is part of the routine immunization schedule for children. (Correct Answer)

Explanation: ***Inactivated polio vaccine (IPV) is part of the routine immunization schedule for children.*** - **IPV is currently included** in India's Universal Immunization Programme (UIP) and is the standard for routine childhood immunization globally. - IPV is **safe and highly effective** at preventing paralytic polio without the risk of vaccine-associated paralytic polio (VAPP). - This is the **most current and directly applicable** statement about poliovirus vaccination practices. *Spastic paralysis* - Poliovirus causes **flaccid paralysis**, not spastic paralysis. - This results from destruction of **anterior horn cells** in the spinal cord, leading to lower motor neuron damage and loss of muscle tone. *Most cases are symptomatic* - This is **incorrect**. Approximately **95% of poliovirus infections are asymptomatic** or cause only mild, non-specific symptoms. - Only **<1% of infections** progress to paralytic poliomyelitis. *Historically, intramuscular injections during the incubation period were thought to increase paralysis risk* - This statement is **historically accurate** (phenomenon called "provocation poliomyelitis"). - However, this is a **historical observation** from the pre-vaccine era, whereas the correct answer reflects **current immunization practice**. - The question asks what is "true about polioviruses," making the current vaccination practice more relevant than historical epidemiological observations.

Question 399: OPV Bivalent vaccine contains:

A. P1 & P2
B. P1, P2 & P3
C. P2 & P3
D. P1 & P3 (Correct Answer)

Explanation: ***P1 & P3*** - The Bivalent Oral Poliovirus Vaccine (bOPV) contains live attenuated strains of **Poliovirus serotypes 1 and 3**. - This vaccine was developed to target the most prevalent circulating **wild poliovirus serotypes** responsible for most polio cases. *P1 & P2* - This combination is not representative of the bivalent OPV. The bOPV specifically focuses on serotypes 1 and 3 because serotype 2 was officially **eradicated in 2015**. - Including serotype 2 could lead to rare cases of **vaccine-associated paralytic poliomyelitis (VAPP)** without significant benefit. *P1, P2 & P3* - This describes the **Trivalent Oral Poliovirus Vaccine (tOPV)**, which was the standard vaccine before the eradication of wild poliovirus type 2. - The tOPV was phased out globally to reduce the risk of **vaccine-derived poliovirus type 2 (VDPV2)**. *P2 & P3* - This combination is not used in current polio vaccination strategies. The global strategy involved removing serotype 2 from routine immunization after its **eradication**. - Focusing on serotypes 2 and 3 would neglect **serotype 1**, which remains a significant threat in endemic regions.

Question 400: Which of the following is the 'Yellow Fever' reference centre?

A. NIV, Pune (Correct Answer)
B. NIN, Hyderabad
C. Central Institute, Kasauli
D. Haffkine Institute, Mumbai

Explanation: ***NIV, Pune*** - The **National Institute of Virology (NIV)** in Pune is the WHO-designated national reference laboratory for Yellow Fever in India. - It serves as a **WHO Collaborating Centre** for arboviral diseases and is responsible for Yellow Fever vaccination, diagnosis, surveillance, and outbreak investigation. - NIV Pune is the authorized center for issuing **International Certificates of Vaccination** for Yellow Fever as required under International Health Regulations. *NIN, Hyderabad* - The **National Institute of Nutrition (NIN)** in Hyderabad focuses on nutrition research, dietary guidelines, and public health nutrition. - It does not serve as a reference center for infectious diseases like Yellow Fever. *Central Institute, Kasauli* - The **Central Research Institute (CRI)** in Kasauli is primarily known as the national reference center for **rabies** and rabies vaccine production. - While it is an important biomedical research institution, it is not the designated Yellow Fever reference center in India. *Haffkine Institute, Mumbai* - The **Haffkine Institute** in Mumbai is a biomedical research institution involved in vaccine production and infectious disease research. - It is not designated as the national reference center for Yellow Fever.

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

Practice Questions

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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