Immunization and Vaccine-Preventable Diseases Practice Questions

Q: Strategies for prevention of Neonatal Tetanus include all of the following except -

Giving penicillin to all the newborns. ***Giving penicillin to all the newborns*** - This is not a recommended strategy for preventing neonatal tetanus. While **penicillin** can treat bacterial infections, it does not prevent neonatal tetanus, which is caused by the toxin produced by *Clostridium tetani*, not the bacterium itself. - The primary prevention of neonatal tetanus focuses on **maternal immunization** and **aseptic delivery practices**, not routine antibiotic prophylaxis for newborns. *5 clean practices* - The "5 cleans" refers to **clean hands**, **clean surface**, **clean cord cutting instrument**, **clean cord tie**, and **clean perineum**. These practices significantly reduce the risk of cord contamination by *Clostridium tetani* spores. - Implementing these practices during delivery and cord care is a crucial and **effective strategy** for preventing neonatal tetanus. *2 doses of TT to all pregnant women* - Administering two doses of **tetanus toxoid (TT) vaccine** to pregnant women provides **active immunity** to the mother, who then transfers protective **maternal antibodies** transplacentally to the newborn, providing **passive immunity** to the infant. - This maternal immunization protects the infant during the vulnerable neonatal period by neutralizing the tetanus toxin. *Immunizing all married women* - Immunizing all married women of childbearing age with **tetanus toxoid** ensures that they are protected against tetanus and can pass on protective antibodies to their future offspring. - This is a broader public health strategy aimed at **eliminating maternal and neonatal tetanus** by ensuring robust population immunity.

Q: According to standard guidelines, post-exposure prophylaxis is routinely recommended after ANY potential exposure for which of the following infections?

Rabies. ***Rabies*** - **Rabies post-exposure prophylaxis (PEP) is ALWAYS recommended** after any potential exposure (Category II/III wounds) **regardless of vaccination status** due to the near 100% fatality rate once symptoms appear. - PEP is initiated immediately and involves **wound care**, administration of **rabies immune globulin (RIG)** for previously unvaccinated individuals, and a series of **rabies vaccines**. - Unlike other infections, there is **no screening or assessment of immune status required** - exposure alone mandates PEP. *HBV* - Hepatitis B post-exposure prophylaxis is **conditional** - recommended only for unvaccinated individuals or those with unknown vaccination status after significant exposure. - Those with documented immunity (anti-HBs >10 mIU/mL) do **not require PEP**. - Not routine for all exposures. *Diphtheria* - Diphtheria post-exposure prophylaxis is recommended **only for close contacts** of confirmed cases, particularly if unvaccinated or uncertain vaccination history. - Fully vaccinated individuals with recent boosters may not require prophylaxis. - Not routine for all potential exposures. *Measles* - Measles post-exposure prophylaxis is recommended **only for susceptible individuals** (unvaccinated or no evidence of immunity). - Those with documented immunity do not require PEP. - Requires assessment of immune status before administration.

Q: All of the following are recognized adverse effects of DPT vaccine:

Fever. ***Fever*** - **Fever** is the most common and expected adverse effect after DPT vaccination due to the body's normal immune response to the vaccine components. - It's usually mild and self-limiting, indicating the immune system is building protection. - Occurs in 30-50% of recipients and is considered a typical reaction rather than a complication. *Seizures* - While rare, **seizures** (febrile or afebrile) have been reported as adverse events following DPT vaccination. - Febrile seizures are more common and usually brief without long-term neurological damage. - The risk is very low (approximately 1 in 14,000 doses), and benefits far outweigh this potential risk. *Abscess* - An **abscess** at the injection site can occur as a local complication, though uncommon. - May result from improper injection technique, contamination, or local tissue reaction. - Requires medical attention and possible drainage. *Encephalopathy* - **Encephalopathy** (serious brain injury) was recognized as an extremely rare severe adverse event associated with the **whole-cell pertussis component** of older DPT vaccines. - Risk estimated at less than 1 in 1 million doses. - Modern DTaP (acellular pertussis) vaccines have largely replaced whole-cell DPT to significantly reduce this risk.

Q: Which of the following statements about HPV vaccination is true?

It has an efficacy greater than 70% for cervical cancer.. ***It has an efficacy greater than 70% for cervical cancer.*** - HPV vaccines are highly effective in preventing **HPV infections**, which are the primary cause of cervical cancer. Studies show they have an efficacy of **over 70%** (and often much higher for certain strains) in preventing cervical precancers and cancers. - The vaccine works by inducing an immune response to the **HPV L1 capsid protein**, which prevents the virus from infecting cells. *It is given to women aged 20-40 years.* - The primary target group for HPV vaccination is **adolescents**, typically aged 9-14 years, before potential exposure to the virus. - While catch-up vaccination may be recommended for young adults up to age 26, routine vaccination in women aged 20-40 years is **less common and less effective** due to likely prior exposure. *The primary dose consists of 2 doses.* - For individuals initiating vaccination before their 15th birthday, the primary dose schedule consists of **2 doses**. - For individuals 15 years and older, a **3-dose schedule** is typically recommended. *There are two types available in the market.* - Currently, there are **three types** of HPV vaccines available globally: bivalent (targeting HPV 16, 18), quadrivalent (targeting HPV 6, 11, 16, 18), and **nonavalent (targeting HPV 6, 11, 16, 18, 31, 33, 45, 52, 58)**. - The specific types available in a particular market may vary, but globally, there are more than two.

Q: What is the correct schedule for pre-exposure prophylaxis for rabies vaccination?

0, 7, 28 days. ***0, 7, 28 days*** - The CDC recommends a **three-dose schedule** for rabies pre-exposure prophylaxis (PrEP) on days 0, 7, and 28 or 21. - This schedule ensures adequate **antibody production** before potential exposure to the rabies virus. *0, 7 days* - This two-dose schedule is typically used for **post-exposure prophylaxis (PEP)** in individuals who are already previously vaccinated, not for initial pre-exposure prophylaxis. - It would not provide sufficient **long-term immunity** for unvaccinated individuals. *0, 3, 7, 14 days* - This schedule is **not the standard** pre-exposure prophylaxis regimen recommended by major health organizations. - While it includes multiple doses, it deviates from the **established and proven 3-dose PrEP schedule**. *0, 3, 7, 14, 30 days* - This is an **overly extensive** and incorrect schedule for routine pre-exposure prophylaxis. - A more frequent and prolonged schedule like this is **unnecessary** and not part of current guidelines for rabies PrEP.

Q: What is the correct dosing schedule for the Japanese encephalitis vaccine?

Single dose vaccine.. ***Single dose vaccine.*** - India uses the **SA 14-14-2 live attenuated Japanese encephalitis vaccine** in its Universal Immunization Programme (UIP). - The schedule consists of a **single dose given at 9-12 months of age** as per the National Immunization Schedule and IAP guidelines. - This single-dose live attenuated vaccine provides **long-lasting immunity** and has been part of India's UIP since 2013 in endemic areas. - The vaccine is **safe, effective, and cost-effective** for mass immunization programs. *Two doses: the second dose is given one month after the first.* - This is not the standard schedule for Japanese encephalitis vaccine used in India. - The live attenuated SA 14-14-2 vaccine requires only a single dose for primary immunization. *Three doses: the second dose is given one month after the first, and the third dose is given six months later.* - This schedule applies to the **inactivated JE vaccine (JE-VC/Ixiaro)**, which is NOT part of India's Universal Immunization Programme. - While this 3-dose schedule (0, 28 days, 6-12 months) is used in some countries and for travelers, it is **not the standard in India** for routine immunization. - For NEET PG and Indian medical exams, focus on the UIP schedule. *Three doses: the second dose is given two weeks after the first, and the third dose is given one month later.* - This is an incorrect schedule and does not correspond to any standard Japanese encephalitis vaccination regimen. - Neither the live attenuated nor the inactivated JE vaccines follow this timing.

Q: MgCl2 is added to polio vaccine for what purpose?

Vaccine can be kept at higher temperatures. ***Vaccine can be kept at higher temperatures*** - Magnesium chloride (**MgCl2**) is used in the **oral polio vaccine (OPV)** to provide **thermostability**, allowing the vaccine to withstand higher temperatures. - This property is crucial for vaccine distribution in regions with **limited cold chain infrastructure**, preventing degradation of the live attenuated virus. *Enhances the vaccine's effectiveness* - While vaccine effectiveness is critical, **MgCl2** does not directly enhance the **immunogenicity** or **potency** of the polio antigens. - Its primary role is related to **stabilization** of the viral particles, not improvement of the immune response generated. *Acts as a preservative* - **Preservatives** like 2-phenoxyethanol or thimerosal are added to vaccines to prevent **microbial growth**. - **MgCl2** acts as a **stabilizer**, protecting the viral structure from heat-induced denaturation, which is distinct from preventing bacterial contamination. *None of the options* - This option is incorrect because **MgCl2** does have a specific and important role in stabilizing the polio vaccine, as explained. - Its ability to confer **thermostability** is a well-established property in vaccine formulation.

Q: Live vaccines are contraindicated in all except:

Breastfeeding mothers. ***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.

Q: Neonatal tetanus prevention is best done by which antenatal measure?

Tetanus toxoid. ***Tetanus toxoid*** - **Tetanus toxoid vaccination** of pregnant women stimulates **active immunity** in the mother, leading to production of protective antibodies. - These maternal IgG antibodies cross the placenta and provide **passive immunity** to the fetus/neonate, protecting against neonatal tetanus. - Neonatal tetanus is often acquired through umbilical stump infection with *Clostridium tetani* spores in unhygienic delivery conditions. - **WHO recommends** at least 2 doses of TT during pregnancy for prevention of neonatal tetanus. *Tetanus immunoglobulin* - **Tetanus immunoglobulin (TIG)** provides immediate **passive immunity**, but its effect is short-lived (3-4 weeks). - It's used for **post-exposure prophylaxis** or treatment in individuals who are unimmunized or inadequately immunized. - Not practical or recommended for routine antenatal prevention due to short duration, high cost, and need for repeated administration. *Antibiotics (e.g., Penicillin)* - While penicillin can be used as part of **tetanus treatment** to kill *Clostridium tetani* bacteria, it does not provide **preventive immunity** to the fetus. - Antibiotics do not neutralize the tetanus toxin or provide antibodies for passive immunity. - They have no role in antenatal prevention of neonatal tetanus. *Antibiotics (e.g., Metronidazole)* - **Metronidazole** is another antibiotic used to treat *Clostridium tetani* infection. - Like penicillin, it does not confer **immunity** (active or passive) to the neonate. - Not an effective antenatal measure for preventing neonatal tetanus.

Q: Which of the following is true about the Sabin vaccine for polio?

Four doses are given in primary immunization.. ***Four doses are given in primary immunization.*** - The **Sabin vaccine** (oral polio vaccine, OPV) is administered in **four doses** during primary immunization in India: at birth, 6 weeks, 10 weeks, and 14 weeks. - This schedule ensures robust and lasting immunity by stimulating both mucosal and systemic immune responses. - The birth dose provides early protection, while subsequent doses at 4-week intervals allow for optimal immune response development. *The doses are given at 1-week intervals.* - The standard immunization schedule for OPV does not involve 1-week intervals; doses are spaced **4 weeks apart** (at 6, 10, and 14 weeks after the birth dose). - Administering doses too closely may not allow for optimal **immune response development** and may not provide sufficient protection. *Given intramuscularly.* - The Sabin vaccine is an **oral vaccine**, administered as drops into the mouth. - Its oral route allows it to induce both humoral and **mucosal immunity** in the gut, which is crucial for preventing intestinal replication of the poliovirus. - The **inactivated polio vaccine (IPV/Salk vaccine)** is the one given intramuscularly. *Contains only 1 strain of the virus.* - The Sabin vaccine used in India is **bivalent OPV (bOPV)**, containing live-attenuated strains of poliovirus **types 1 and 3**. - India switched from trivalent OPV (tOPV - types 1, 2, 3) to bivalent OPV in 2016 following the global withdrawal of type 2-containing vaccines after eradication of wild poliovirus type 2. - Monovalent vaccines (mOPV) may be used for outbreak responses in specific situations.

Question 1

Strategies for prevention of Neonatal Tetanus include all of the following except -

Accepted Answer

Giving penicillin to all the newborns

Answer

2 doses of TT to all pregnant women

Answer

Immunizing all married women

Answer

5 clean practices

Question 2

According to standard guidelines, post-exposure prophylaxis is routinely recommended after ANY potential exposure for which of the following infections?

Accepted Answer

Rabies

Answer

HBV

Answer

Diphtheria

Answer

Measles

Question 3

All of the following are recognized adverse effects of DPT vaccine:

Accepted Answer

Fever

Answer

Seizures

Answer

Abscess

Answer

Encephalopathy

Question 4

Which of the following statements about HPV vaccination is true?

Accepted Answer

It has an efficacy greater than 70% for cervical cancer.

Answer

It is given to women aged 20-40 years.

Answer

The primary dose consists of 2 doses.

Answer

There are two types available in the market.

Question 5

What is the correct schedule for pre-exposure prophylaxis for rabies vaccination?

Accepted Answer

0, 7, 28 days

Answer

0, 7 days

Answer

0, 3, 7, 14 days

Answer

0, 3, 7, 14, 30 days

Question 6

What is the correct dosing schedule for the Japanese encephalitis vaccine?

Accepted Answer

Single dose vaccine.

Answer

Two doses: the second dose is given one month after the first.

Answer

Three doses: the second dose is given one month after the first, and the third dose is given six months later.

Answer

Three doses: the second dose is given two weeks after the first, and the third dose is given one month later.

Question 7

MgCl2 is added to polio vaccine for what purpose?

Accepted Answer

Vaccine can be kept at higher temperatures

Answer

Enhances the vaccine's effectiveness

Answer

Acts as a preservative

Answer

None of the options

Question 8

Live vaccines are contraindicated in all except:

Accepted Answer

Breastfeeding mothers

Answer

Pregnant women

Answer

Immunocompromised patients

Answer

Patients on high-dose immunosuppressants

Question 9

Neonatal tetanus prevention is best done by which antenatal measure?

Accepted Answer

Tetanus toxoid

Answer

Tetanus immunoglobulin

Answer

Antibiotics (e.g., Penicillin)

Answer

Antibiotics (e.g., Metronidazole)

Question 10

Which of the following is true about the Sabin vaccine for polio?

Accepted Answer

Four doses are given in primary immunization.

Answer

Given intramuscularly.

Answer

Contains only 1 strain of the virus.

Answer

The doses are given at 1-week intervals.

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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