Immunization and Vaccine-Preventable Diseases Practice Questions

Q: OPV Bivalent vaccine contains:

P1 & P3. ***P1 & P3*** - The Bivalent Oral Poliovirus Vaccine (bOPV) contains live attenuated strains of **Poliovirus serotypes 1 and 3**. - This vaccine was developed to target the most prevalent circulating **wild poliovirus serotypes** responsible for most polio cases. *P1 & P2* - This combination is not representative of the bivalent OPV. The bOPV specifically focuses on serotypes 1 and 3 because serotype 2 was officially **eradicated in 2015**. - Including serotype 2 could lead to rare cases of **vaccine-associated paralytic poliomyelitis (VAPP)** without significant benefit. *P1, P2 & P3* - This describes the **Trivalent Oral Poliovirus Vaccine (tOPV)**, which was the standard vaccine before the eradication of wild poliovirus type 2. - The tOPV was phased out globally to reduce the risk of **vaccine-derived poliovirus type 2 (VDPV2)**. *P2 & P3* - This combination is not used in current polio vaccination strategies. The global strategy involved removing serotype 2 from routine immunization after its **eradication**. - Focusing on serotypes 2 and 3 would neglect **serotype 1**, which remains a significant threat in endemic regions.

Q: True about rotavirus vaccine:

Given orally. ***Given orally*** - Rotavirus vaccines are **live attenuated vaccines** administered orally to stimulate localized immunity in the gastrointestinal tract. - This oral route is crucial for inducing **mucosal immunity**, which is important for protection against rotavirus infection. *Killed vaccine* - The rotavirus vaccine is an **attenuated live vaccine**, meaning it contains weakened forms of the virus, not killed ones. - Live attenuated vaccines generally provide a **stronger and longer-lasting immune response** compared to killed vaccines. *Should be given before 5 years* - The rotavirus vaccine series is recommended to be completed in **infancy**, typically before 8 months of age, depending on the specific vaccine brand and schedule. - Giving the vaccine at too old an age increases the (still very small) risk of **intussusception** and a lack of efficacy. *Given subcutaneous* - Rotavirus vaccines are administered by the **oral route**, not subcutaneously. - The **subcutaneous route** is used for various other vaccines, but not for rotavirus.

Q: All of the following are true about measles except?

Secondary attack rate is 30%. ***Secondary attack rate is 30%*** - The **secondary attack rate** for measles is extremely high, typically around **90%** in susceptible household contacts, making it one of the most contagious infectious diseases. - A rate of 30% would imply a much lower transmissibility than what is characteristically observed for measles. *I.P. = 7-14 days* - The **incubation period (I.P.)** for measles is typically 7-14 days from exposure to the onset of fever. - This is a well-established and accurate timeframe for the disease. *Best age for immunization is 9-12 months* - The **first dose** of the measles-mumps-rubella (MMR) vaccine is generally recommended between **9-12 months** of age in many parts of the world, especially in endemic areas, to provide early protection. - This timing balances the waning of maternal antibodies with the need for effective immunization. *Maximum incidence in 6m-3 year age group* - In areas with lower vaccination coverage, measles incidence is indeed highest in **preschool-aged children**, particularly those between 6 months and 3 years, as maternal antibodies wane and they become more exposed. - This age group is highly susceptible due to their developing immune systems and social interactions.

Q: All are included in acute flaccid paralysis surveillance, except -

Transient weakness. ***Transient weakness*** - **Surveillance for acute flaccid paralysis (AFP)** focuses on persistent flaccid weakness, not temporary or transient weakness. The goal is to identify and investigate cases that could be **poliomyelitis** or other serious neurological conditions causing lasting paralysis. - While transient weakness might be a symptom in some conditions, it is not a criterion for inclusion in standard AFP surveillance, which specifically looks for **acute onset** and progressive or sustained flaccidity. *Age* - **Age** is a crucial component of AFP surveillance, particularly because poliomyelitis primarily affects **children under 15 years old**. Surveillance systems often target this age group to maximize the chances of detecting polio cases. - Data on the age of affected individuals is used to track epidemiological patterns and assess the effectiveness of **vaccination programs**. *No cause* - Cases where **no cause** is immediately apparent are specifically included in AFP surveillance to ensure that all potential cases of **poliomyelitis** are investigated. This is particularly important in regions working towards polio eradication. - Investigating cases with no obvious cause helps to rule out polio and identify other **etiologies of flaccid paralysis**, contributing to a broader understanding of neurological diseases. *Tone* - The assessment of **muscle tone** is fundamental to defining flaccid paralysis. **Reduced or absent muscle tone (flaccidity)** is a defining characteristic of AFP. - **Tone** helps differentiate AFP from other forms of paralysis (e.g., spastic paralysis) and guides the diagnostic workup for conditions like **Guillain-Barré Syndrome** or poliomyelitis.

Q: About Vi polysaccharide vaccine, true is:

Can be given in patients with yellow fever and hepatitis B. ***Can be given in patients with yellow fever and hepatitis B*** - There are **no contraindications** for administering the **Vi polysaccharide vaccine** to individuals with **yellow fever** or **hepatitis B**. These conditions do not interfere with the vaccine's safety or efficacy. - The Vi polysaccharide vaccine is specifically designed to protect against **typhoid fever** and is generally safe, even in immunocompromised individuals or those with concurrent infections. *Has many serious local side effects* - The **Vi polysaccharide vaccine** is known for its **mild local side effects**, typically limited to pain, redness, or swelling at the injection site. - **Serious local reactions** are **rare** and not a characteristic feature of this vaccine. *Has many serious systemic side effects* - The **Vi polysaccharide vaccine** generally has a **good safety profile** with **few systemic side effects**. - Systemic reactions, if they occur, are usually mild and transient, such as low-grade fever or headache, rather than serious. *Has many contraindications* - The **Vi polysaccharide vaccine** has **few contraindications**. The main contraindication is a **severe allergic reaction** to a previous dose or any vaccine component. - It is safe for use in most populations, including individuals with chronic diseases, and does not have a large list of conditions that would prevent its administration.

Q: Best means of giving hepatitis B vaccine is

Intramuscular deltoid. ***Intramuscular deltoid*** - The **deltoid muscle** is the recommended site for hepatitis B vaccine administration in adults and older children due to its muscle mass and distance from major nerves and vessels. - This route ensures proper absorption and immunogenicity, leading to an optimal **antibody response**. *Intradermal* - This route is typically reserved for vaccines that require a small dose and a localized immune response, such as the **BCG vaccine**. - It's not recommended for hepatitis B vaccine as it can lead to reduced efficacy and a less robust immune response. *Subcutaneous* - **Subcutaneous administration** might be considered in individuals with bleeding disorders, but it generally leads to a less consistent and potentially weaker immune response for hepatitis B vaccination. - It's a second-line route when intramuscular injection is contraindicated, not the primary method. *Intramuscular gluteal* - The **gluteal muscle** is not the preferred site for vaccines due to the risk of injury to the **sciatic nerve** and the potential for injection into adipose tissue rather than muscle, which can compromise vaccine efficacy. - While intramuscular, absorption can be less predictable compared to the deltoid, especially in adults.

Q: Which of the following is a currently recommended vaccine for rabies post-exposure prophylaxis?

HDCV. ***HDCV*** - **Human Diploid Cell Vaccine (HDCV)** is a modern, highly effective, and safe vaccine widely recommended for both pre-exposure and post-exposure rabies prophylaxis. - It is prepared with virus grown in **human diploid cell cultures**, ensuring higher purity and fewer side effects compared to older vaccines. *Duck embryo vaccine* - The duck embryo vaccine was an older type of rabies vaccine that is **no longer recommended** due to its lower potency and higher incidence of adverse reactions. - It was derived from inactivated rabies virus grown in **duck embryos**. *Semple* - The Semple vaccine, also known as the **nervous tissue vaccine**, was historically significant but is now **obsolete** because of severe neurological complications associated with its use. - It was prepared from the brains of rabies-infected animals and contained **myelin basic protein**, leading to encephalitis in some recipients. *Suckling mouse brain vaccine* - The suckling mouse brain vaccine was another older vaccine that is **no longer recommended** in many countries. - While an improvement over Semple, it still carried a risk of **neurological side effects** due to residual neural tissue components.

Q: True regarding pertussis vaccine is:

Erythromycin should be given to contacts. ***Erythromycin should be given to contacts*** - **Erythromycin** or other macrolides are recommended for close contacts of pertussis patients to prevent secondary cases, especially in vulnerable populations. - This **post-exposure prophylaxis** helps to eradicate *Bordetella pertussis* from the nasopharynx, reducing transmission. *Leucocytosis is diagnostic* - While **leukocytosis** with **lymphocytosis** is characteristic of pertussis, especially in infants, it is a supportive finding rather than definitively diagnostic on its own. - **PCR testing** or culture of nasopharyngeal secretions is required for definitive diagnosis. *95% of vaccinated individuals are protected* - The effectiveness of pertussis vaccines (DTaP and Tdap) is generally high, but it is typically around **80-85%**, not 95%, and **waning immunity** is common over time. - Protection is not absolute, and vaccinated individuals can still contract pertussis, although usually in a milder form. *Neuroparalytic complication is seen in 1 in 15,000* - **Serious adverse events** like encephalopathy or neuroparalytic complications following pertussis vaccination are **extremely rare**, with estimates much lower than 1 in 15,000. - Most reactions are mild and localized, such as pain or swelling at the injection site.

Q: A 30-year-old man reports 4 hours after acquiring a clean wound without laceration. He had received TT vaccination 10 years back. What do you advise regarding tetanus prophylaxis?

single dose of TT. ***single dose of TT*** - For a **clean wound** in a patient who received a **TT vaccination 10 years ago**, a single dose of **Tetanus Toxoid (TT)** is sufficient to boost immunity. - This patient's previous vaccination history provides a baseline immunity, and a booster ensures continued protection against tetanus. *No vaccination needed* - Even with a "clean" wound, if the last vaccination was 10 years ago, the patient's **antibody levels** might be insufficient for full protection against tetanus. - Tetanus is a serious, often fatal, disease, making prophylaxis crucial even for minor wounds. *1 dose of TT AND TIG* - **Tetanus immunoglobulin (TIG)** is reserved for **dirty or contaminated wounds** or for individuals with an **unknown or incomplete vaccination history**. - In this case, the wound is clean and the patient has prior vaccination, so TIG is not indicated. *full course of TT* - A **full course of TT** (multiple doses) is typically recommended for individuals with an **unknown or incomplete vaccination history** to establish primary immunity. - Since this patient had a vaccination 10 years ago, they already possess foundational immunity, and only a booster is required.

Q: Protective level of Tetanus anti-toxin is:

>0.01 IU/mL. ***>0.01 IU/mL*** - A serum level of antibodies **greater than 0.01 IU/mL** is generally considered the **minimum protective level** against tetanus. - This threshold indicates sufficient immunity to prevent clinical tetanus, though higher levels offer an increased margin of protection. *>0.5 IU/mL* - While levels **above 0.5 IU/mL** indicate strong, long-lasting protection, they are not the minimum protective threshold. - This level is often considered indicative of **excellent immunity** that may last for many years. *>5 IU/mL* - A level of **5 IU/mL** or higher signifies a very high antibody titer, far exceeding the basic protective level. - This level is not the standard for basic protection and often seen after **recent vaccination** or booster. *>1.0 IU/mL* - Levels **above 1.0 IU/mL** indicate very good protection, but this is a higher threshold than the minimal protective level. - It suggests a robust immune response, but not the absolute lowest concentration required for immunity.

Question 1

OPV Bivalent vaccine contains:

Accepted Answer

P1 & P3

Answer

P1 & P2

Answer

P1, P2 & P3

Answer

P2 & P3

Question 2

True about rotavirus vaccine:

Accepted Answer

Given orally

Answer

Killed vaccine

Answer

Should be given before 5 years

Answer

Given subcutaneous

Question 3

All of the following are true about measles except?

Accepted Answer

Secondary attack rate is 30%

Answer

I.P. = 7-14 days

Answer

Best age for immunization is 9-12 months

Answer

Maximum incidence in 6m-3 year age group

Question 4

All are included in acute flaccid paralysis surveillance, except -

Accepted Answer

Transient weakness

Answer

Age

Answer

No cause

Answer

Tone

Question 5

About Vi polysaccharide vaccine, true is:

Accepted Answer

Can be given in patients with yellow fever and hepatitis B

Answer

Has many serious local side effects

Answer

Has many serious systemic side effects

Answer

Has many contraindications

Question 6

Best means of giving hepatitis B vaccine is

Accepted Answer

Intramuscular deltoid

Answer

Intradermal

Answer

Subcutaneous

Answer

Intramuscular gluteal

Question 7

Which of the following is a currently recommended vaccine for rabies post-exposure prophylaxis?

Accepted Answer

HDCV

Answer

Duck embryo vaccine

Answer

Semple

Answer

Suckling mouse brain vaccine

Question 8

True regarding pertussis vaccine is:

Accepted Answer

Erythromycin should be given to contacts

Answer

Leucocytosis is diagnostic

Answer

95% of vaccinated individuals are protected

Answer

Neuroparalytic complication is seen in 1 in 15,000

Question 9

A 30-year-old man reports 4 hours after acquiring a clean wound without laceration. He had received TT vaccination 10 years back. What do you advise regarding tetanus prophylaxis?

Accepted Answer

single dose of TT

Answer

No vaccination needed

Answer

1 dose of TT AND TIG

Answer

full course of TT

Question 10

Protective level of Tetanus anti-toxin is:

Accepted Answer

>0.01 IU/mL

Answer

>0.5 IU/mL

Answer

>5 IU/mL

Answer

>1.0 IU/mL

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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