Community Medicine
7 questionsWhich of the following is an example of a case-control study?
Immunity starts after how many days of yellow fever vaccination ?
Which Diphtheria vaccine is recommended for a 14-year-old girl?
Droplet nuclei is a type of ?
Which of the following is an example of indirect transmission by a living vector?
Which vaccine is the most widely used globally in childhood vaccination programs, aside from the Oral Polio Vaccine (OPV)?
Which of the following infectious diseases has the highest proportion of asymptomatic chronic carriers?
NEET-PG 2015 - Community Medicine NEET-PG Practice Questions and MCQs
Question 711: Which of the following is an example of a case-control study?
- A. Framingham heart study
- B. PVC exposure and angiosarcoma of the liver (Correct Answer)
- C. Doll & Hill Study
- D. Thalidomide exposure and its association with teratogenicity
Explanation: ***PVC exposure and angiosarcoma of the liver*** - This is a classic example of a **case-control study** where individuals with a rare disease (angiosarcoma of the liver) are identified (cases) and compared to a control group without the disease to determine past exposures (PVC). - The study looked back in time to identify differences in exposure between cases and controls. *Framingham heart study (cohort study)* - The Framingham Heart Study is a well-known **prospective cohort study** that has followed participants over time to observe the development of cardiovascular disease. - In a cohort study, researchers identify a group of individuals and follow them forward in time to see who develops the outcome of interest, making it different from a case-control design. *Doll & Hill Study (cohort study)* - The Doll & Hill study is a landmark **cohort study** that investigated the association between smoking and lung cancer by following a group of British doctors over several years. - This study started with healthy individuals and observed them over time to see who developed lung cancer, which is characteristic of a cohort design. *Thalidomide exposure and its association with teratogenicity* - While the thalidomide tragedy led to crucial epidemiological investigations, the initial identification of the association was often through **case series** or **descriptive epidemiology**, noting an unusual clustering of rare birth defects among infants whose mothers took thalidomide. - Subsequent studies might have incorporated case-control elements, but the prompt asks for an example of a case-control study, and this event itself is generally cited for its role in pharmacovigilance and observational studies rather than a single, classic case-control study example in the way "PVC and angiosarcoma" is.
Question 712: 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 713: 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 714: Droplet nuclei is a type of ?
- A. Direct transmission of infectious agents
- B. Vertical transmission of pathogens
- C. Biological transmission of pathogens
- D. Indirect transmission of pathogens (Correct Answer)
Explanation: ***Indirect transmission of pathogens*** - **Droplet nuclei** are tiny airborne particles remaining after the evaporation of respiratory droplets, suspended in the air for prolonged periods, allowing pathogens to travel over longer distances. - This mode of transmission is considered **indirect** because it involves an environmental medium (air) rather than direct contact between individuals. *Vertical transmission of pathogens* - This refers to the transmission of a pathogen from a **mother to her offspring**, either during pregnancy, childbirth, or breastfeeding. - Examples include HIV and rubella, which are transmitted directly from parent to child, unlike airborne droplet nuclei. *Direct transmission of infectious agents* - This involves immediate physical contact or exposure between an infected individual and a susceptible host (e.g., touching, kissing, sexual contact). - It does not involve an intermediate environmental vehicle such as airborne particles that travel through the air from their source. *Biological transmission of pathogens* - This type of transmission involves an **arthropod vector** that not only transmits the pathogen but also allows it to multiply or develop within its body before transmission. - Examples include malaria transmitted by mosquitoes or Lyme disease by ticks, which is distinct from airborne droplet nuclei transmission.
Question 715: Which of the following is an example of indirect transmission by a living vector?
- A. Transmission by mosquito (Correct Answer)
- B. Vertical transmission
- C. Soil contact
- D. Droplet infection
Explanation: ***Transmission by mosquito*** - This is the classic example of **vector-borne transmission**, where a living biological vector (the mosquito) acts as an intermediary to transmit the infectious agent from an infected host to a susceptible one. - The disease-causing microorganism does not pass directly from person to person but is carried and transmitted by the living vector. - Examples include malaria, dengue, and filariasis. *Vertical transmission* - This refers to transmission of disease from a **mother to her child** during pregnancy, childbirth, or breastfeeding. - This is a form of **direct transmission** where the pathogen passes directly between biologically related individuals without an intermediate living vector. *Soil contact* - This represents **vehicle-borne transmission** where soil acts as a non-living vehicle (fomite) carrying pathogens. - While this is technically indirect transmission, it does not involve a **living biological vector** as specified in the question. - Examples include tetanus, hookworm, and ascariasis transmitted through contaminated soil. *Droplet infection* - This is a form of **direct transmission** where infectious droplets are expelled from the respiratory tract of an infected person and directly contact the mucous membranes of a susceptible person. - The droplets travel a short distance in close proximity, representing direct person-to-person transfer without any intermediate vector.
Question 716: 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 717: Which of the following infectious diseases has the highest proportion of asymptomatic chronic carriers?
- A. Measles
- B. Rabies
- C. Diphtheria
- D. Hepatitis B (Correct Answer)
Explanation: ***Hepatitis B*** - **Hepatitis B** infection has a significant proportion of **chronic asymptomatic carriers**, particularly when infection occurs perinatally or in early childhood. - In adults, approximately **5% develop chronic infection** after acute exposure, and many of these chronic carriers remain asymptomatic while maintaining infectivity. - Chronic carriers can harbor the virus for years or decades without clinical symptoms, making them an important reservoir for transmission. - This is a major public health concern as asymptomatic carriers can unknowingly transmit the virus. *Measles* - **Measles** is highly contagious and typically presents with **symptomatic disease** in nearly all infected individuals. - Clinical features include characteristic maculopapular rash, cough, coryza, conjunctivitis, and Koplik's spots. - Asymptomatic infection is **extremely rare** with measles virus. *Diphtheria* - While **asymptomatic pharyngeal carriage** of *Corynebacterium diphtheriae* can occur, it is not the predominant pattern. - Clinical diphtheria typically presents with pseudomembrane formation, sore throat, and potential systemic toxin effects. - Carrier rates vary but are not as epidemiologically significant as with Hepatitis B. *Rabies* - **Rabies** is almost **100% symptomatic** once the virus reaches the central nervous system. - There is **no chronic asymptomatic carrier state** in humans. - Once clinical symptoms appear (encephalitis, hydrophobia, paralysis), the disease is virtually always fatal.
Dermatology
1 questionsWhich area is typically not involved in a chickenpox rash?
NEET-PG 2015 - Dermatology NEET-PG Practice Questions and MCQs
Question 711: Which area is typically not involved in a chickenpox rash?
- A. Trunk
- B. Axilla
- C. Back
- D. Palms and soles (Correct Answer)
Explanation: ***Palms and soles*** - The chickenpox rash, caused by the **varicella-zoster virus**, typically spares the palms and soles. - Chickenpox exhibits a characteristic **centripetal distribution** (center-predominant), with lesions most numerous on the trunk and progressively fewer on the extremities. - **Sparing of palms and soles** is a classic differentiating feature from other viral exanthems like hand-foot-and-mouth disease. *Trunk* - The **trunk** is usually the **most heavily involved area** in a chickenpox rash, with lesions often appearing first and being most numerous here. - This is the hallmark of the characteristic **centripetal distribution** of the rash. *Axilla* - The **axilla** is a common site for chickenpox lesions due to its location on the trunk and the presence of **warm, moist skin folds** that can favor lesion development. - The rash tends to be widespread, making secondary sites like the axilla commonly involved. *Back* - The **back** is a major part of the trunk and is therefore extensively involved in a chickenpox rash. - The rash often starts on the trunk and spreads outwards, ensuring significant involvement of the back.
Obstetrics and Gynecology
1 questionsAfter taking MMR live vaccine, conception should not occur within ?
NEET-PG 2015 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 711: After taking MMR live vaccine, conception should not occur within ?
- A. 4 weeks (Correct Answer)
- B. 8 weeks
- C. 2 weeks
- D. 10 weeks
Explanation: ***4 weeks*** - The **MMR (measles, mumps, and rubella) vaccine** is a **live attenuated vaccine**, meaning it contains weakened forms of the viruses. - To minimize any theoretical risk of congenital rubella syndrome, women are advised to **avoid conception for at least 4 weeks** (or one month) after receiving the MMR vaccine. *2 weeks* - This period is generally considered too short for ensuring the complete clearance of the attenuated live virus from the woman's system before conception. - The standard recommendation for live attenuated vaccines like MMR is typically longer due to potential, though rare, viral transmission risks to the fetus. *8 weeks* - While a longer waiting period like 8 weeks would certainly be safe, it is **not the minimum recommended duration** by public health guidelines. - Waiting 4 weeks (one month) is sufficient and a more practical guideline for most women planning conception. *10 weeks* - This duration is significantly longer than the standard recommendation and is not necessary to ensure safety after an MMR vaccination. - The 4-week guideline balances safety with practicality for reproductive planning.
Pharmacology
1 questionsWhich of the following vaccines is not freeze-dried?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 711: Which of the following vaccines is not freeze-dried?
- A. Measles Vaccine
- B. Diphtheria, Pertussis, and Tetanus (DPT) Vaccine (Correct Answer)
- C. Rubella Vaccine
- D. BCG Vaccine
Explanation: ***Diphtheria, Pertussis, and Tetanus (DPT) Vaccine*** - The DPT vaccine is a **liquid vaccine** that contains inactivated toxins and bacterial components, making it stable in liquid form. - It does not require **freeze-drying** because its components are chemically stable and do not degrade significantly in solution. *Measles Vaccine* - The measles vaccine is a **live attenuated vaccine** that needs to be freeze-dried to maintain the viability and stability of the live virus. - Freeze-drying helps preserve the vaccine's potency by removing water, which prevents degradation during storage and transport. *Rubella Vaccine* - Similar to the measles vaccine, the rubella vaccine is a **live attenuated vaccine** and is therefore provided in a freeze-dried form. - This process ensures the long-term stability and efficacy of the viral components, which would otherwise degrade in a liquid state. *BCG Vaccine* - The BCG (Bacillus Calmette-Guérin) vaccine is a **live attenuated bacterial vaccine** used against tuberculosis, and it is also manufactured as a freeze-dried product. - Freeze-drying is essential for maintaining the viability of the live attenuated *Mycobacterium bovis* strain.