Types of Vaccines — MCQs
Which of the following vaccines is currently used as a live attenuated vaccine in routine immunization programs?
Mass vaccination is ineffective in inducing 'herd immunity' for:
Which of the following vaccines is classified as a killed vaccine?
The following statements are true about DPT vaccine except
Which of the following is not a polysaccharide vaccine?
Live vaccines are contraindicated in all except:
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 ?
True about chicken pox -
Which virus is NOT associated with human cancer?
A child after consuming food in a party complains of diarrhea within 1-5 hours. The diagnosis is:
Types of Vaccines Indian Medical PG Practice Questions and MCQs
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
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.
Question 2: Mass vaccination is ineffective in inducing 'herd immunity' for:
- A. Poliomyelitis
- B. Tetanus (Correct Answer)
- C. None of the options
- D. Measles
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
Question 3: Which of the following vaccines is classified as a killed vaccine?
- A. Varicella
- B. BCG
- C. OPV
- D. Meningococcal vaccine (Correct Answer)
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.
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
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.
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)
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.
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
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.
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
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.
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
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.
Question 9: Which virus is NOT associated with human cancer?
- A. HPV
- B. Measles virus (Correct Answer)
- C. HHV-8
- D. EBV
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.
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
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.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free