Polio Eradication — MCQs
Which of the following is NOT a core component of the WHO's global STI control strategy?
Poliomyelitis is diagnosed by:
An elderly man who had been in several military conflicts during the early 1980s and received blood transfusions for injuries recently consulted his physician for a diagnosis of cryoglobulinemia and glomerulonephritis. Additional testing revealed that he was infected with a virus transmitted through blood. Which virus was involved in this infection?
Salk vaccine is a:
In an epidemic of poliomyelitis, the best way to stop spread is by -
Key indicator for AFP surveillance?
The National Health Policy 2002 target to be achieved by the year 2010 is :
All of the following are global targets for WHO Global Action Plan (2013–2020) for Prevention and Control of NCDs, EXCEPT:
BCG vaccine should be administered:
What is the duration of immunity provided by the yellow fever vaccine, and when does it begin?
Polio Eradication Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is NOT a core component of the WHO's global STI control strategy?
- A. Case management
- B. Universal mandatory screening (Correct Answer)
- C. Strategic information systems
- D. Prevention services
Explanation: ***Universal mandatory screening*** - While screening is part of STI control, **universal mandatory screening** for all STIs in the general population is not a core component of the WHO's strategy due to feasibility, cost, and ethical considerations. - The strategy emphasizes **targeted screening** for at-risk populations and opportunistic screening. *Case management* - **Case management**, including accurate diagnosis and effective treatment, is a critical component for managing current infections and preventing further transmission. - This involves syndromic or etiologic approaches to treatment and partner notification. *Strategic information systems* - **Strategic information systems** are essential for monitoring trends, evaluating interventions, and informing policy decisions related to STI control. - This includes surveillance data, program monitoring, and research. *Prevention services* - **Prevention services** are a cornerstone of the WHO's strategy, aiming to reduce the incidence of new infections. - These services encompass health education, condom promotion and distribution, vaccination, and pre-exposure prophylaxis (PrEP).
Question 2: Poliomyelitis is diagnosed by:
- A. Clinical presentation
- B. Antibody titer measurement in blood
- C. Isolation of virus from blood
- D. Isolation of virus from stool (Correct Answer)
Explanation: ***Isolation of virus from stool*** - Viral culture from **stool samples** is the most reliable method for diagnosing poliomyelitis, as the **poliovirus** is shed in feces for several weeks after infection. - This method confirms the presence of the live virus, which is crucial for distinguishing between active infection and prior exposure or vaccination. *Clinical presentation* - The clinical presentation of poliomyelitis, such as **flaccid paralysis**, can be similar to other neurological conditions, making it non-specific for definitive diagnosis. - A definitive diagnosis requires laboratory confirmation to differentiate it from other causes of **acute flaccid paralysis**, such as **Guillain-Barré syndrome**. *Antibody titer measurement in blood* - While antibody titers can indicate **exposure to poliovirus**, they do not differentiate between recent infection, past infection, or vaccination. - A significant rise in **antibody titers** between acute and convalescent phase samples might suggest recent infection, but it's not practical for rapid diagnosis. *Isolation of virus from blood* - **Poliovirus** is rarely isolated from the blood, as **viremia** is typically transient and occurs early in the infection before the onset of overt symptoms. - Detection of the virus in blood indicates an early stage of systemic spread but is less likely to be positive once neurological symptoms manifest.
Question 3: An elderly man who had been in several military conflicts during the early 1980s and received blood transfusions for injuries recently consulted his physician for a diagnosis of cryoglobulinemia and glomerulonephritis. Additional testing revealed that he was infected with a virus transmitted through blood. Which virus was involved in this infection?
- A. Hepatitis A Virus (HAV)
- B. Hepatitis B Virus (HBV)
- C. Hepatitis C Virus (HCV) (Correct Answer)
- D. Hepatitis D Virus (HDV)
Explanation: ***Hepatitis C Virus (HCV)*** - HCV infection is a common cause of **mixed cryoglobulinemia** and can lead to **glomerulonephritis**, particularly membranoproliferative glomerulonephritis. - Before widespread screening of the blood supply, HCV was a significant risk from **blood transfusions**, especially for individuals who received them in the early 1980s [1]. *Hepatitis A Virus (HAV)* - HAV is primarily transmitted via the **fecal-oral route** and does not typically cause chronic infection or lead to cryoglobulinemia or glomerulonephritis. - It causes **acute, self-limiting hepatitis** and is not associated with blood transfusions in the context described. *Hepatitis B Virus (HBV)* - While HBV can be transmitted through blood and can cause glomerulonephritis (e.g., membranous nephropathy), it is less commonly associated with **cryoglobulinemia** in comparison to HCV. - The constellation of cryoglobulinemia and glomerulonephritis, especially with a history of transfusions in the 1980s, points more strongly to HCV. *Hepatitis D Virus (HDV)* - HDV is a **defective virus** that requires co-infection with HBV to replicate. - While it can cause severe liver disease, it is not primarily associated with **cryoglobulinemia** or glomerulonephritis as a direct cause, but rather exacerbates HBV-related complications.
Question 4: Salk vaccine is a:
- A. Live vaccine
- B. Inactivated vaccine (Correct Answer)
- C. Attenuated vaccine
- D. Inactivated toxin
Explanation: ***Inactivated vaccine*** - The **Salk vaccine** is an **inactivated poliovirus vaccine (IPV)** that uses chemically inactivated (killed) wild-type poliovirus strains. - This inactivation process renders the virus unable to replicate or cause disease, while still retaining its **antigenicity** to elicit an immune response. - The Salk vaccine is administered by **intramuscular injection** and provides systemic immunity. *Live vaccine* - **Live vaccines** contain live, replicating organisms that are either attenuated (weakened) or fully virulent. - The **Sabin vaccine** (oral poliovirus vaccine - OPV) is an example of a live attenuated vaccine for polio, not the Salk vaccine. - The Salk vaccine contains completely inactivated virus and is therefore not a live vaccine. *Attenuated vaccine* - **Attenuated vaccines** contain live but weakened forms of the pathogen, which can replicate to a limited extent in the host without causing disease. - Examples include MMR, varicella, and the **Sabin vaccine** for polio. - The Salk vaccine uses **inactivated virus**, not attenuated virus, making this option incorrect. *Inactivated toxin* - An **inactivated toxin**, also known as a **toxoid vaccine**, is derived from bacterial toxins that have been rendered harmless but still stimulate an immune response. - Examples include **tetanus and diphtheria vaccines**, which target bacterial toxins rather than whole viruses. - The Salk vaccine targets the **poliovirus itself**, not a toxin produced by the virus.
Question 5: In an epidemic of poliomyelitis, the best way to stop spread is by -
- A. OPV drops to all children (Correct Answer)
- B. Isolation of cases
- C. Chlorination of all wells
- D. Injection of killed vaccine
Explanation: ***OPV drops to all children*** - **Oral Polio Vaccine (OPV)** contains live, attenuated virus that replicates in the gut and provides both individual immunity and **herd immunity** by shedding modified virus, thus reducing transmission in an epidemic. - Administering OPV to all children during an epidemic is crucial because it quickly boosts population immunity and **blocks the fecal-oral transmission** pathway of the poliovirus. *Isolation of cases* - While isolation of affected individuals can reduce spread for some diseases, **poliovirus** can be shed asymptomatically for weeks, making isolation alone an ineffective strategy for epidemic control. - Poliovirus transmission is primarily through the **fecal-oral route**, and asymptomatic carriers can continue to spread the infection, undermining isolation efforts. *Chlorination of all wells* - **Chlorination of water sources** is important for general public health and preventing waterborne diseases, but it is not the most effective primary intervention for stopping an established polio epidemic. - While polio can be waterborne, **person-to-person fecal-oral transmission** is the dominant route, which is not directly addressed by water chlorination. *Injection of killed vaccine* - The **inactivated polio vaccine (IPV)**, given by injection, provides excellent individual immunity to paralytic polio but induces less intestinal immunity compared to OPV. - Due to lower intestinal immunity, IPV recipients can still replicate and shed the virus in their gut, potentially continuing **environmental transmission** during an epidemic, making it less effective for immediate epidemic control compared to OPV.
Question 6: Key indicator for AFP surveillance?
- A. At least one case of non-polio AFP per year per 100000 population of under 15 years (Correct Answer)
- B. At least one case of non-polio AFP per year per 1000 population of under 5 years
- C. At least one case of non-polio AFP per year per 10000 population of under 15 years
- D. At least one case of non-polio AFP per year per 100000 population of under 5 years
Explanation: ***At least one case of non-polio AFP per year per 100000 population of under 15 years*** - This indicator, often referred to as the **non-polio AFP rate**, is a crucial measure for assessing the sensitivity and effectiveness of **Acute Flaccid Paralysis (AFP) surveillance**. - A rate of at least 1 non-polio AFP case per 100,000 population under 15 years acts as a **robust benchmark** to ensure that the surveillance system is sensitive enough to detect all potential polio cases. *At least one case of non-polio AFP per year per 1000 population of under 5 years* - This option incorrectly modifies both the **population denominator** (1,000 instead of 100,000) and the **age group** (under 5 years instead of under 15 years) for standard AFP surveillance. - While children under 5 are a high-risk group for polio, the surveillance target is broader to capture all AFP cases, and the benchmark rate is specific to a larger population denominator. *At least one case of non-polio AFP per year per 10000 population of under 15 years* - This option uses an incorrect **population denominator** of 10,000, which would suggest a surveillance system that is less sensitive than the established standard for effective AFP detection. - The correct benchmark uses a 100,000 population denominator to ensure adequate detection of rare cases. *At least one case of non-polio AFP per year per 100000 population of under 5 years* - This option correctly uses the **100,000 population denominator** but incorrectly restricts the age group to **under 5 years**. - AFP surveillance aims to detect cases in individuals up to 15 years of age to effectively monitor for **poliovirus circulation**.
Question 7: The National Health Policy 2002 target to be achieved by the year 2010 is :
- A. Reduce infant mortality rate 30/1000 live births (Correct Answer)
- B. Elimination of leprosy
- C. Eradication of polio
- D. Achieve zero level growth of HIV/AIDS
Explanation: ***Reduce infant mortality rate 30/1000 live births*** - The **National Health Policy 2002** specifically set the target of reducing **Infant Mortality Rate (IMR) to 30 per 1000 live births by the year 2010**. - This was one of the key quantifiable goals with a clear timeline aligned with the question's timeframe. - The policy document explicitly mentioned this as a priority target for improving maternal and child health outcomes in India. *Eradication of polio* - While **polio eradication** was indeed a major objective of the National Health Policy 2002, the target year was **2005, not 2010**. - India achieved polio-free status in 2014 when WHO certified the country as polio-free. - This makes it incorrect for the specific year 2010 mentioned in the question. *Elimination of leprosy* - The **elimination of leprosy** (defined as prevalence of less than 1 case per 10,000 population) was targeted for **2005, not 2010**. - India achieved national level elimination in December 2005, though some districts continued to have higher prevalence. - This target predates the 2010 timeline asked in the question. *Achieve zero level growth of HIV/AIDS* - The National Health Policy 2002 aimed to **halt and reverse the HIV/AIDS epidemic** by 2007. - The specific phrase "zero level growth" and the year 2010 do not accurately reflect the policy's stated objectives. - The focus was on stabilizing prevalence and preventing new infections through NACP (National AIDS Control Programme).
Question 8: All of the following are global targets for WHO Global Action Plan (2013–2020) for Prevention and Control of NCDs, EXCEPT:
- A. A 30% relative reduction in mean population intake of salt/sodium
- B. A 25% relative reduction in risk of premature mortality from cardiovascular diseases, cancer, diabetes and chronic respiratory diseases
- C. At least 10 % relative reduction in the harmful use of alcohol
- D. A 15% relative reduction in healthcare costs related to NCDs (Correct Answer)
Explanation: ***A 15% relative reduction in healthcare costs related to NCDs*** - While reducing healthcare costs is an important outcome of NCD prevention, it was **not explicitly stated as one of the nine global targets** in the WHO Global Action Plan (2013–2020) for the Prevention and Control of NCDs. - The targets primarily focused on **risk factor reduction and mortality reduction**, rather than direct cost reduction percentages. *A 30% relative reduction in mean population intake of salt/sodium* - This is one of the **specified global targets** of the WHO NCD Global Action Plan, aiming to reduce a significant dietary risk factor for cardiovascular diseases. - High sodium intake is a major contributor to **hypertension**, a leading risk factor for NCDs. *A 25% relative reduction in risk of premature mortality from cardiovascular diseases, cancer, diabetes and chronic respiratory diseases* - This represents the **overarching mortality reduction target** for the key NCDs, making it a central goal of the WHO action plan. - Reducing premature mortality is a direct measure of the **effectiveness of NCD prevention and control strategies**. *At least 10 % relative reduction in the harmful use of alcohol* - This is another **identified global target** within the WHO NCD Global Action Plan, recognizing alcohol as a major modifiable risk factor for NCDs. - Harmful alcohol use contributes to various NCDs, including **liver disease, cardiovascular disease, and certain cancers**.
Question 9: BCG vaccine should be administered:
- A. Immediately after birth (Correct Answer)
- B. At the age of 1 month
- C. At the age of 6 months
- D. At the age of 1 year
Explanation: **Explanation:** **1. Why Option A is Correct:** According to the National Immunization Schedule (NIS) in India and WHO guidelines, the **BCG (Bacillus Calmette-Guérin)** vaccine should be administered **at birth** or as soon as possible thereafter. The primary medical rationale is to provide early protection against severe, disseminated forms of childhood tuberculosis, specifically **Tubercular Meningitis** and **Miliary Tuberculosis**. Since newborns in endemic areas are at immediate risk of exposure, early vaccination ensures the induction of cell-mediated immunity before natural infection occurs. **2. Why Other Options are Incorrect:** * **Options B, C, and D:** While BCG can be given up to the age of one year if missed at birth, these are not the *recommended* times for administration. Delaying the vaccine increases the window of vulnerability for the infant. Furthermore, if the vaccine is delayed beyond birth, the dose changes (0.05 ml at birth vs. 0.1 ml after 4 weeks), and if delayed beyond one year, it is generally not recommended under the NIS as the protective efficacy diminishes. **3. High-Yield Clinical Pearls for NEET-PG:** * **Dose:** 0.05 ml (until 1 month of age); 0.1 ml (beyond 1 month up to 1 year). * **Route:** Strictly **Intradermal** (left upper arm) using an Omega/Tuberculin syringe. * **Strain:** Danis 1331 is the most commonly used strain in India. * **Diluent:** Normal Saline (NS). Never use Distilled Water (causes irritation/sterile abscess). * **The Phenomenon:** A papule forms, followed by a crust and a permanent **pitted scar** (the only vaccine to leave a characteristic scar). * **Direct BCG:** In India, BCG is given "directly" without a prior Mantoux test up to 1 year of age.
Question 10: What is the duration of immunity provided by the yellow fever vaccine, and when does it begin?
- A. 6 years starting from 6 days after vaccination
- B. 6 years starting from 10 days after vaccination
- C. 10 years starting from 6 days after vaccination
- D. 10 years starting from 10 days after vaccination (Correct Answer)
Explanation: **Explanation:** The **Yellow Fever vaccine (17D strain)** is a live-attenuated vaccine that provides robust immunity. According to the **International Health Regulations (IHR)**, the validity of the vaccination certificate for international travel traditionally begins **10 days** after the date of vaccination. This 10-day window is the time required for the body to develop protective neutralizing antibodies. **Why Option D is Correct:** Historically, the immunity was documented to last for **10 years**, and the certificate required a booster every decade. While the WHO updated its position in 2016 stating that a single dose provides life-long protection, for the purpose of **NEET-PG and International Health Regulations (IHR)**, the legal validity of the certificate remains defined as starting from **10 days** post-vaccination and lasting for **10 years** (though many countries now accept it as valid for life). **Analysis of Incorrect Options:** * **Options A & B:** The duration of 6 years is incorrect. This figure is often confused with the validity period of the Cholera vaccine certificate (which is 6 months, not years). * **Option C:** While the duration is 10 years, the immunity is not legally recognized until the 10th day. The 6-day period is irrelevant to Yellow Fever protocols. **High-Yield Clinical Pearls for NEET-PG:** * **Strain:** 17D strain (grown in chick embryo). * **Route/Dose:** 0.5 ml, Subcutaneous. * **Contraindications:** Infants <6 months, egg allergy, thymic disease, and symptomatic HIV/immunocompromised states. * **Cold Chain:** It is highly heat-sensitive; must be stored between **+2°C to +8°C** (or frozen at -50°C to -15°C at central levels). * **Rule of 10:** Remember **10 days to 10 years** for easy recall of certificate validity.
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