Types of Vaccines Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Types of Vaccines. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Types of Vaccines Indian Medical PG Question 1: Which of the following vaccines is currently used as a live attenuated vaccine in routine immunization programs?
- A. Measles (Correct Answer)
- B. Inactivated Polio Vaccine (IPV)
- C. Smallpox
- D. Cholera
Types of Vaccines Explanation: ***Measles***- The **measles vaccine** is a **live attenuated vaccine** that induces a strong and long-lasting immune response against the measles virus.- It is a core component of routine childhood immunization programs globally, often given as part of the **MMR (Measles, Mumps, Rubella)** vaccine.*Inactivated Polio Vaccine (IPV)*- **IPV** is an **inactivated (killed) vaccine** that contains polioviruses grown in culture and then chemically inactivated. [1]- It is administered via injection and produces systemic immunity without the risk of vaccine-associated paralytic poliomyelitis (VAPP).*Smallpox*- The **smallpox vaccine** contained a **live vaccinia virus**, which is related to smallpox but much safer.- While it was a live vaccine, smallpox has been eradicated, and routine vaccination is no longer practiced except for specific laboratory personnel.*Cholera*- Most commonly used cholera vaccines are either **inactivated (killed whole-cell)** vaccines or **live attenuated oral vaccines**.- While a live attenuated oral cholera vaccine exists, it is not part of routine childhood immunization programs in most countries, but rather used in specific outbreak settings or for travelers.
Types of Vaccines Indian Medical PG Question 2: Mass vaccination is ineffective in inducing 'herd immunity' for:
- A. Poliomyelitis
- B. Tetanus (Correct Answer)
- C. None of the options
- D. Measles
Types of Vaccines Explanation: ***Tetanus (Correct Answer)***
- **Herd immunity** relies on reducing person-to-person transmission, which is not applicable to tetanus as it is acquired through **environmental exposure** (soil contaminated with *Clostridium tetani* spores), not human contact
- Vaccination against tetanus provides **individual protection only** and does not prevent disease spread within a population, making mass vaccination ineffective for herd immunity
- Tetanus is a **non-communicable disease** - immunity in others does not protect unvaccinated individuals
*Poliomyelitis (Incorrect)*
- Mass vaccination for poliomyelitis has been highly effective in establishing **herd immunity**, leading to near-global eradication
- The vaccine prevents viral shedding and breaks the chain of transmission
- High vaccination coverage protects unvaccinated individuals through reduced viral circulation
*Measles (Incorrect)*
- Mass vaccination against measles is extremely effective in inducing **herd immunity** due to its high transmissibility (R₀ = 12-18)
- Requires **~95% vaccination coverage** to maintain herd immunity
- Classic example where high vaccination rates protect vulnerable individuals who cannot be vaccinated
*None of the options (Incorrect)*
- This is incorrect because tetanus is a clear example where mass vaccination does **not** induce herd immunity
- The disease's environmental transmission pattern makes herd immunity irrelevant for disease control
Types of Vaccines Indian Medical PG Question 3: Which of the following vaccines is classified as a killed vaccine?
- A. Varicella
- B. BCG
- C. OPV
- D. Meningococcal vaccine (Correct Answer)
Types of Vaccines Explanation: ***Meningococcal vaccine***
- The meningococcal conjugate and polysaccharide vaccines are **killed vaccines**, containing inactivated bacterial components (polysaccharides) that stimulate an immune response.
- They provide protection against *Neisseria meningitidis* and are considered safe for most populations due to their non-live nature.
*Varicella*
- The varicella vaccine is a **live-attenuated vaccine**, meaning it contains a weakened form of the **varicella-zoster virus**.
- This attenuated virus can replicate in the recipient, eliciting a strong and long-lasting immune response, similar to natural infection.
*BCG*
- The **Bacillus Calmette-Guérin (BCG)** vaccine is a **live-attenuated vaccine** used to prevent tuberculosis.
- It contains a weakened strain of **_Mycobacterium bovis_**, which is closely related to *Mycobacterium tuberculosis* but has lost its virulence.
*OPV*
- The **Oral Polio Vaccine (OPV)** is a **live-attenuated vaccine** that contains weakened but live strains of all three poliovirus serotypes.
- It induces strong mucosal immunity in the gut, which is crucial for preventing the wild poliovirus from replicating and spreading.
Types of Vaccines Indian Medical PG Question 4: The following statements are true about DPT vaccine except
- A. Whole killed bacteria of Bordetella pertussis has an adjuvant effect
- B. Presence of acellular pertussis component increases its immunogenicity (Correct Answer)
- C. Aluminium salt has an adjuvant effect
- D. Presence of Hemophilus influenza type B component increases the immunogenicity of pertussis component
Types of Vaccines Explanation: ***Presence of acellular pertussis component increases its immunogenicity***
- This statement is **incorrect** and is the answer to this "except" question.
- **Acellular pertussis (aP)** vaccines were developed primarily to **reduce side effects and reactogenicity**, not to increase immunogenicity.
- aP vaccines contain purified components (2-5 antigens) compared to whole-cell pertussis (wP) which contains the entire killed bacterium.
- **Immunogenicity comparison:** aP vaccines provide **shorter-lived immunity** and may require more boosters compared to wP vaccines, indicating they are not superior in immunogenicity.
*Whole killed bacteria of Bordetella pertussis has an adjuvant effect*
- **TRUE statement.** Whole-cell pertussis (wP) vaccines naturally possess **adjuvant properties** due to complex bacterial components including lipopolysaccharides (LPS).
- These components stimulate strong innate immune responses, leading to robust and longer-lasting immunity, though with more reactogenicity.
*Aluminium salt has an adjuvant effect*
- **TRUE statement.** Aluminium salts (aluminium hydroxide or phosphate) are standard adjuvants in DPT vaccines.
- They enhance immune response through **depot effect** (prolonged antigen release), activation of innate immunity, and recruitment of antigen-presenting cells to the injection site.
*Presence of Hemophilus influenza type B component increases the immunogenicity of pertussis component*
- **TRUE statement.** When Hib is combined with DPT (forming pentavalent vaccine), each component elicits an **independent immune response** against its specific target.
- Hib component does **NOT enhance** the immunogenicity of the pertussis, diphtheria, or tetanus components - they maintain their individual immunogenic properties without mutual enhancement.
Types of Vaccines Indian Medical PG Question 5: Which of the following is not a polysaccharide vaccine?
- A. Pneumococcal vaccine
- B. Meningococcal vaccine
- C. H. Influenzae B vaccine
- D. Hepatitis B vaccine (Correct Answer)
Types of Vaccines Explanation: ***Hepatitis B vaccine (recombinant protein vaccine)***
- This is a **recombinant protein vaccine** which contains **HBsAg** (Hepatitis B surface antigen) produced in yeast.
- As it uses a protein antigen, it is not a polysaccharide vaccine.
*Pneumococcal vaccine (includes polysaccharide forms)*
- There are two types: **Pneumococcal Polysaccharide Vaccine (PPSV23)** which is a pure polysaccharide vaccine, and **Pneumococcal Conjugate Vaccine (PCV13, PCV15, PCV20)** which contains polysaccharides conjugated to a protein carrier.
- Both types utilize **polysaccharide antigens** from *Streptococcus pneumoniae* to elicit an immune response.
*Meningococcal vaccine (includes polysaccharide forms)*
- Similar to pneumococcal vaccines, there are **meningococcal polysaccharide vaccines (MPSV4)** and **meningococcal conjugate vaccines (MCV4)**.
- These vaccines use **polysaccharides** from the capsule of *Neisseria meningitidis* as their immunogenic component, either alone or conjugated.
*H. Influenza B vaccine (conjugate vaccine derived from polysaccharides)*
- This is a **conjugate vaccine** that uses a **polysaccharide capsule antigen** from *Haemophilus influenzae type B* (Hib) chemically linked to a protein carrier.
- Conjugation improves immunogenicity, especially in infants, by converting the T-independent polysaccharide antigen into a T-dependent one.
Types of Vaccines Indian Medical PG Question 6: Live vaccines are contraindicated in all except:
- A. Breastfeeding mothers (Correct Answer)
- B. Pregnant women
- C. Immunocompromised patients
- D. Patients on high-dose immunosuppressants
Types of Vaccines Explanation: ***Breastfeeding mothers***
- Live vaccines are generally **safe for breastfeeding mothers** and their infants, as the vaccine viruses are not typically excreted in breast milk in levels that can infect the infant.
- The benefits of vaccinating the mother outweigh any theoretical risks, and it can provide **passive immunity** to the infant through antibodies in breast milk.
*Pregnant women*
- Live vaccines are **contraindicated during pregnancy** due to the theoretical risk of transmitting the attenuated virus to the fetus and causing congenital infection.
- Examples include **MMR** and **varicella vaccines**, which should be administered before or after pregnancy.
*Immunocompromised patients*
- Live vaccines are **contraindicated** in individuals with compromised immune systems due to the risk of the attenuated vaccine virus causing **disseminated infection** or severe disease.
- This includes patients with **HIV/AIDS** (with low CD4 counts), congenital immunodeficiencies, and those undergoing active cancer treatment.
*Patients on high-dose immunosuppressants*
- These patients are considered **immunocompromised**, and live vaccines are **contraindicated** because their suppressed immune system may not be able to effectively control the attenuated vaccine virus, leading to severe infection.
- Examples of such medications include high-dose corticosteroids, chemotherapy agents, and biologics that target immune cells.
Types of Vaccines Indian Medical PG Question 7: Consider the following statements regarding splenectomy :
1. It corrects anemia in congenital hereditary spherocytosis.
2. Postponed until the age of 4 years if possible.
3. Polyvalent pneumococcal vaccine to be administered to all before the surgery. Which of the statements given above are correct ?
- A. 1, 2 and 3 (Correct Answer)
- B. 1 and 3 only
- C. 2 and 3 only
- D. 1 and 2 only
Types of Vaccines Explanation: ***1, 2 and 3***
- **Splenectomy** is a definitive treatment for **hereditary spherocytosis**, as it removes the primary site of red blood cell destruction, thereby correcting the **anemia**.
- Delaying splenectomy until after **4 years of age** reduces the risk of **overwhelming post-splenectomy infection (OPSI)**, allowing the child's immune system to mature. *Note: This reflects 2009 guidelines when this question was set. Current guidelines recommend postponing splenectomy until 5-6 years or even older (6-9 years) to further minimize OPSI risk.*
- **Vaccination** against encapsulated bacteria like **Streptococcus pneumoniae** (using a polyvalent vaccine) is crucial before splenectomy to prevent severe infections, as the spleen plays a vital role in clearing these pathogens.
*1 and 3 only*
- This option is incorrect because it omits the important recommendation to **postpone splenectomy** until the child is older, which is a key part of managing hereditary spherocytosis in children.
*2 and 3 only*
- This option is incorrect because it fails to acknowledge that **splenectomy effectively corrects the anemia** in congenital hereditary spherocytosis by eliminating the site of premature red blood cell destruction, which is a primary indication for the procedure.
*1 and 2 only*
- This option is incorrect because it overlooks the critical need for **vaccination** against encapsulated bacteria **before splenectomy** to protect against life-threatening infections, a standard and essential practice.
Types of Vaccines Indian Medical PG Question 8: True about chicken pox -
- A. Rash is deep seated
- B. Caused by varicella-zoster virus (Correct Answer)
- C. SAR is 70%
- D. Scab is infective
Types of Vaccines Explanation: ***Caused by varicella-zoster virus***
- Chickenpox, also known as varicella, is definitively caused by the **varicella-zoster virus (VZV)**, a member of the herpesvirus family.
- VZV is highly contagious and responsible for both primary infection (chickenpox) and latent infection (shingles).
*Rash is deep seated*
- The rash of chickenpox is characteristically **superficial**, appearing as vesicles on the epidermis and upper dermis, often described as "dewdrops on a rose petal."
- Deep-seated lesions are more characteristic of diseases like **smallpox**, which results in deeper scarring.
*SAR is 70%*
- The **secondary attack rate (SAR)** for chickenpox in susceptible household contacts is much higher than 70%, typically ranging from **80% to 90%**, highlighting its extreme contagiousness.
- This high SAR means that most unvaccinated individuals living with an infected person will contract the disease.
*Scab is infective*
- While scabs contain the virus, the **infectivity significantly decreases** once the lesions have crusted over and formed scabs.
- The most infective stages are typically from 1-2 days before the rash appears until all lesions have crusted.
Types of Vaccines Indian Medical PG Question 9: Which virus is NOT associated with human cancer?
- A. HPV
- B. Measles virus (Correct Answer)
- C. HHV-8
- D. EBV
Types of Vaccines Explanation: ***Measles virus***
- The **measles virus** (rubeola) is primarily known for causing acute febrile illness with a characteristic rash and is not recognized as an **oncogenic virus** in humans.
- While it can cause significant morbidity and mortality, particularly in unvaccinated populations, its mode of action does not involve **cellular transformation** or sustained **oncogene expression**.
*HPV*
- **Human Papillomavirus (HPV)**, particularly high-risk types like HPV-16 and HPV-18, is a well-established cause of **cervical cancer**, as well as other anogenital and oropharyngeal cancers.
- HPV oncogenes, **E6** and **E7**, interfere with tumor suppressor proteins like p53 and Rb, promoting uncontrolled cell growth.
*HHV-8*
- **Human Herpesvirus 8 (HHV-8)**, also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the causative agent of **Kaposi's sarcoma**, a vascular tumor.
- HHV-8 is also associated with primary effusion lymphoma and multicentric Castleman's disease due to its **latency-associated nuclear antigen (LANA)** and other viral oncogenes.
*EBV*
- **Epstein-Barr Virus (EBV)** is strongly linked to several human cancers, including **Burkitt's lymphoma**, **nasopharyngeal carcinoma**, and Hodgkin's lymphoma.
- EBV transforms B lymphocytes through the expression of latency genes such as **LMP1** and **EBNA2**, which modulate cell growth and survival pathways.
Types of Vaccines Indian Medical PG Question 10: A child after consuming food in a party complains of diarrhea within 1-5 hours. The diagnosis is:
- A. S. aureus (Correct Answer)
- B. Clostridium perfringens
- C. Streptococcus
- D. Clostridium botulinum
Types of Vaccines Explanation: ***S. aureus***
- **_Staphylococcus aureus_** food poisoning has a rapid onset (**1-6 hours**) because symptoms are caused by preformed **exotoxins** ingested with contaminated food, not by bacterial growth in the host.
- Common sources include foods handled extensively and left at **room temperature**, allowing the bacteria to multiply and produce heat-stable toxins.
*Clostridium perfringens*
- **_Clostridium perfringens_** food poisoning typically has a longer incubation period (**6-24 hours**), as symptoms are caused by toxins produced by bacteria replicating in the host intestine.
- It often results from eating large quantities of contaminated meat or poultry that has been improperly cooked or stored.
*Streptococcus*
- **_Streptococcus_** species are not primary causes of acute **foodborne diarrheal illness** with such a rapid onset.
- While some strains can cause infections, their role in common food poisoning with preformed toxins is negligible compared to _S. aureus_.
*Clostridium botulinum*
- **_Clostridium botulinum_** causes **botulism**, a severe neuroparalytic illness, not primarily diarrhea, and typically has a longer incubation period (**12-36 hours**).
- Symptoms are due to neurotoxins affecting the nervous system, leading to **flaccid paralysis**, not acute gastroenteritis.
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