Immunization and Vaccine-Preventable Diseases Practice Questions

Q: What is the minimum interval between the administration of two live vaccines, such as MMR and Varicella?

4 weeks. ***4 weeks*** - Administering live vaccines simultaneously is generally recommended; however, if not given on the same day, a minimum interval of **4 weeks (28 days)** is necessary. - This interval allows the immune system to fully respond to the first vaccine, preventing potential interference with the replication and efficacy of the second live vaccine. - **Standard recommendation** by CDC, WHO, and IAP for spacing non-simultaneous live vaccines. *2 weeks* - A 2-week interval is generally **too short** for optimal immune response and to prevent potential interference between two live vaccines. - Insufficient time might lead to **reduced seroconversion rates** for the second vaccine, as the immune system is still processing the first. *6 weeks* - While a 6-week interval is safe and effective, it is **not the minimum required interval** between two live vaccines if not given on the same day. - Waiting longer than necessary may **delay protection** against preventable diseases without providing additional immunological benefit compared to the 4-week interval. *8 weeks* - An 8-week interval is also safe but **exceeds the minimum recommended timeframe** for live vaccine administration if not co-administered. - Prolonging the interval beyond 4 weeks **does not enhance efficacy** and may leave the individual susceptible to disease for a longer period.

Q: Polio is said to be eradicated if no case of polio by wild poliovirus occurs in an area for ?

3 years. ***3 years*** - The World Health Organization (WHO) certification criteria for **polio eradication** requires that no new cases of wild poliovirus-caused poliomyelitis be recorded for a minimum of **three consecutive years** in a defined geographical area. - This timeframe is chosen to ensure that all possible chains of transmission have been interrupted and that the virus is no longer circulating in the population. *1 year* - While one year without cases is a positive sign, it is generally considered **insufficient** to declare eradication due to the possibility of **undetected transmission** or a long incubation period for some cases. - Many infectious diseases require a longer period of surveillance to confirm eradication definitively. *2 years* - Similar to one year, a two-year period is often considered **too short** to confidently declare polio eradicated. - The risk of **re-emergence** from undetected or imported cases is still significant in this timeframe. *4 years* - While a four-year period would provide even greater assurance, the standard and internationally accepted criterion for declaring polio eradication is **three years**. - This duration balances the need for robust confirmation with the practicality of ongoing surveillance efforts.

Q: Dose of rabies immunoglobulin for post-exposure prophylaxis?

20 IU/kg. ***20 IU/kg*** - The recommended dose for **rabies immunoglobulin (RIG)** for post-exposure prophylaxis is **20 IU/kg** of body weight. - This dose is crucial for providing immediate passive immunity primarily by infiltrating around the wound, while the active immune response to the vaccine develops. *10 IU/kg* - This dose is **insufficient** to provide adequate passive immunity against rabies after exposure. - Using a lower dose could compromise the effectiveness of post-exposure prophylaxis. *30 IU/kg* - Administering **30 IU/kg** is a higher dose than recommended and does not provide additional benefit. - Such an excessive dose could lead to **unnecessary cost and potential side effects**, without improving protection. *40 IU/kg* - This dose is **significantly higher** than the recommended amount for rabies immunoglobulin. - Overdosing can lead to side effects and is **wasteful of resources**, particularly with a biologic product like RIG.

Q: Which of the following is NOT a criterion for measles elimination?

Transmission at low level. ***Transmission at low level*** - Measles **elimination** strictly requires the **absence of endemic measles virus transmission**, not merely a low level of transmission. - Low-level transmission indicates ongoing circulation of the virus, which is incompatible with the definition of elimination. *Absence of continuous measles virus transmission* - This is a fundamental criterion for measles elimination, signifying that **endemic transmission has been interrupted** for at least 12 months in the presence of a well-performing surveillance system. - It means that any detected cases are either **imported** or linked to an imported source, without sustained local spread. *Incidence rate 95%)* - Achieving and maintaining high vaccination coverage, especially with two doses of measles-containing vaccine, is crucial for establishing and sustaining **herd immunity**. - High coverage at both national and subnational levels is essential to prevent outbreaks and ensure the long-term success of elimination efforts.

Q: Which vaccine should not be frozen?

HBV. ***HBV*** - **Hepatitis B vaccine** (HBV) contains an **aluminum adjuvant** (aluminum hydroxide or aluminum phosphate), which is **irreversibly damaged by freezing**. - Freezing causes the adjuvant to form **large aggregates**, leading to loss of **potency and immunogenicity**, rendering the vaccine ineffective. - **WHO and CDC guidelines** strictly prohibit freezing of aluminum-adjuvanted vaccines. *OPV* - **Oral polio vaccine** (OPV) is a **live attenuated vaccine** that is **stable when frozen**. - It is stored at **-20°C for long-term storage** to maintain its **viability over extended periods**. - Freezing is **recommended** for OPV preservation. *Measles* - The **measles vaccine** should ideally be **stored at 2-8°C** and **not frozen** according to standard guidelines. - However, measles vaccine is **more freeze-tolerant** than aluminum-adjuvanted vaccines and some formulations can withstand brief freezing. - **HBV remains the classic answer** for vaccines that should not be frozen due to the aluminum adjuvant sensitivity. *Yellow fever* - The **yellow fever vaccine** is a **live attenuated vaccine** that is **stable when frozen**. - Stored at **-20°C or colder** for long-term storage to preserve its **potency and effectiveness**. - Freezing is **recommended** for yellow fever vaccine preservation.

Q: What is the PRIMARY indication for cholera vaccination according to WHO recommendations?

For individuals in endemic areas. ***For individuals in endemic areas*** - **Cholera vaccination** is PRIMARY recommended by WHO for populations living in cholera-endemic areas as part of a comprehensive cholera prevention and control strategy. - This is the **most important indication** as it protects vulnerable populations with sustained high-risk exposure and can reduce disease burden in settings where cholera is a persistent public health problem. - WHO emphasizes integration with water, sanitation, and hygiene (WASH) improvements for maximum impact. *To control cholera outbreaks* - While cholera vaccination **can be used** during outbreaks (reactive vaccination), this is a secondary strategy. - The **primary outbreak control measures** remain: rapid case management, WASH interventions, surveillance, and contact tracing. - Vaccination during outbreaks faces logistical challenges and delayed protection (requires 2 doses, immunity takes time to develop). *For travelers to endemic regions* - Cholera vaccination **is recommended** for certain travelers to endemic areas, especially those with limited access to safe water/food. - However, this represents a **much smaller target population** compared to endemic area residents and is not the primary public health indication. - Most travelers have lower risk than residents and can protect themselves through food/water precautions. *For neonates at risk* - **Cholera vaccines are NOT recommended** for neonates (infants under 28 days). - Current oral cholera vaccines are only approved for children ≥1 year of age (varies by vaccine type). - Neonates have low cholera risk and are protected by maternal antibodies and caregiver hygiene practices.

Q: In a 10-year-old school child, which of the following vaccines is given as a part of the school immunization program?

TT/Td vaccine. ***TT/Td vaccine*** - The **tetanus toxoid (TT)** or **tetanus and diphtheria (Td) vaccine** is commonly administered to school-aged children as a booster to maintain immunity against these diseases. - This is part of many national immunization programs, including those in schools, to ensure continued protection beyond early childhood vaccinations. *Measles vaccine* - The **measles vaccine (MMR)** is typically given at 9-12 months and a second dose around 4-6 years of age, much earlier than 10 years. - While essential, it's usually completed before a child reaches the age of 10 for primary vaccination. *Rotavirus vaccine* - The **rotavirus vaccine** is administered to infants, usually before 6 months of age, to protect against severe rotavirus gastroenteritis. - It is not part of school immunization programs for 10-year-olds. *Hepatitis B vaccine* - The **Hepatitis B vaccine** is typically given at birth and completed during infancy, with a series of doses before 1 year of age. - While crucial for early protection, it is not a routine vaccination for 10-year-olds within a school immunization program unless for catch-up reasons.

Q: Mission Indradhanush is for:

Universal immunization. ***Universal immunization*** - **Mission Indradhanush** is a flagship program launched by the Government of India in 2014 to achieve **full immunization coverage** for children and pregnant women. - The mission aims to immunize children against 12 vaccine-preventable diseases, including diphtheria, whooping cough, tetanus, polio, tuberculosis, measles, hepatitis B, and meningitis/pneumonia caused by Haemophilus influenzae type b. *Non-communicable diseases* - Programs for **non-communicable diseases** typically focus on screening, early detection, and management of conditions like diabetes, hypertension, and cancer. - While important for public health, this is not the primary focus of Mission Indradhanush, which targets infectious diseases. *Family planning* - **Family planning programs** aim to provide information and access to contraception and reproductive health services to individuals and couples. - This is a distinct public health initiative separate from the immunization efforts of Mission Indradhanush. *Safe water and sanitation* - Initiatives for **safe water and sanitation** focus on improving access to clean drinking water and proper waste disposal systems to prevent waterborne and sanitation-related diseases. - While crucial for preventing many infections, this is not within the scope of Mission Indradhanush's primary objective of increasing vaccine coverage.

Q: Which vaccine is recommended to be given every year?

Influenza vaccine. ***Influenza vaccine*** - The **influenza virus** constantly mutates, leading to new strains emerging each year. - Annual vaccination is recommended to provide protection against the most prevalent strains predicted for the upcoming flu season. - This is the only vaccine that requires yearly administration due to **antigenic drift**. *Hepatitis A vaccine* - The Hepatitis A vaccine provides **long-term immunity** after a two-dose series. - It does not require annual administration after the initial series is completed. *Varicella (Chickenpox) vaccine* - The Varicella vaccine (typically a two-dose series) offers **durable immunity** against chickenpox. - Annual vaccination is not necessary as protection typically lasts for many years. *Hepatitis B vaccine* - The Hepatitis B vaccine series (usually three doses) provides **long-lasting protection** against the Hepatitis B virus. - Routine annual boosters are not required for individuals who have completed the primary series.

Q: Which of the following statements about the MR vaccination campaign launched by WHO is false?

India has not yet launched this campaign.. ***India has not yet launched this campaign.*** - This statement is **false** because India has actively participated in the **MR vaccination campaign**, reaching millions of children. - The campaign is a key component of India's efforts to eliminate measles and control rubella. *Children from 9 months to less than 15 years are vaccinated.* - This statement is **true** because the age group for the MR vaccination campaign is typically **9 months to 15 years**, aiming to provide widespread immunity. - This age range targets both infants susceptible to measles and older children who may not have received previous vaccinations. *Congenital rubella syndrome (CRS) is responsible for irreversible birth defects.* - This statement is **true** as **Congenital Rubella Syndrome (CRS)** can lead to severe and **irreversible birth defects**, including heart anomalies, deafness, and cataracts, if a pregnant woman contracts rubella. - The MR vaccine protects against rubella, thereby preventing CRS in future generations. *The MR campaign is a one-time campaign and it is followed up by routine immunization* - This statement is **true** because the **MR campaign** is typically a large-scale, one-time catch-up initiative aimed at quickly boosting immunity in a population. - After the campaign, **routine immunization programs** continue to administer MR vaccine doses to ensure sustained protection against measles and rubella in newborns.

Question 1

What is the minimum interval between the administration of two live vaccines, such as MMR and Varicella?

Accepted Answer

4 weeks

Answer

6 weeks

Answer

2 weeks

Answer

8 weeks

Question 2

Polio is said to be eradicated if no case of polio by wild poliovirus occurs in an area for ?

Accepted Answer

3 years

Answer

1 year

Answer

2 years

Answer

4 years

Question 3

Dose of rabies immunoglobulin for post-exposure prophylaxis?

Accepted Answer

20 IU/kg

Answer

40 IU/kg

Answer

10 IU/kg

Answer

30 IU/kg

Question 4

Which of the following is NOT a criterion for measles elimination?

Accepted Answer

Transmission at low level

Answer

Absence of continuous measles virus transmission

Answer

Incidence rate < 1 per million population

Answer

High vaccination coverage (>95%)

Question 5

Which vaccine should not be frozen?

Accepted Answer

HBV

Answer

OPV

Answer

Measles

Answer

Yellow fever

Question 6

What is the PRIMARY indication for cholera vaccination according to WHO recommendations?

Accepted Answer

For individuals in endemic areas

Answer

To control cholera outbreaks

Answer

For travelers to endemic regions

Answer

For neonates at risk

Question 7

In a 10-year-old school child, which of the following vaccines is given as a part of the school immunization program?

Accepted Answer

TT/Td vaccine

Answer

Measles vaccine

Answer

Rotavirus vaccine

Answer

Hepatitis B vaccine

Question 8

Mission Indradhanush is for:

Accepted Answer

Universal immunization

Answer

Non-communicable diseases

Answer

Family planning

Answer

Safe water and sanitation

Question 9

Which vaccine is recommended to be given every year?

Accepted Answer

Influenza vaccine

Answer

Hepatitis A vaccine

Answer

Varicella (Chickenpox) vaccine

Answer

Hepatitis B vaccine

Question 10

Which of the following statements about the MR vaccination campaign launched by WHO is false?

Accepted Answer

India has not yet launched this campaign.

Answer

The MR campaign is a one-time campaign and it is followed up by routine immunization

Answer

Congenital rubella syndrome (CRS) is responsible for irreversible birth defects.

Answer

Children from 9 months to less than 15 years are vaccinated.

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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