Immunization and Vaccine-Preventable Diseases Practice Questions

Q: Two viral vaccines are expected to reduce the incidence of cancers. Which vaccines are these?

HPV 16/18 and hepatitis B vaccines. ***HPV 16/18 and hepatitis B vaccines*** - The **HPV vaccine** (targeting types 16 and 18) protects against human papillomavirus infections, which are the primary cause of cervical cancer and are also linked to other anogenital and oropharyngeal cancers. - The **Hepatitis B vaccine** prevents chronic hepatitis B infection, a major risk factor for hepatocellular carcinoma (liver cancer). *Measles virus and rubella virus vaccines* - The measles and rubella vaccines protect against highly contagious viral diseases but are **not directly associated** with cancer prevention. - While viral infections can sometimes contribute to cancer development indirectly (e.g., chronic inflammation), these specific vaccines do not prevent cancer. *HAV and poliovirus vaccines* - The HAV (Hepatitis A virus) vaccine prevents hepatitis A, which causes acute liver inflammation but **does not lead to chronic infection or liver cancer**. - The poliovirus vaccine prevents poliomyelitis, a neurological disease, and has no known direct link to cancer prevention. *Adenovirus and mumps virus vaccines* - Adenovirus vaccines target various respiratory and gastrointestinal infections and are not linked to cancer prevention. - The mumps virus vaccine protects against mumps, a parotitis-causing infection, and has **no established direct role** in reducing cancer incidence.

Q: Vaccination causing intussusception is

Rotavirus. ***Rotavirus*** - **Rotavirus vaccine** has been associated with a small, but statistically significant, increased risk of **intussusception**, particularly with earlier vaccine formulations. - The mechanism is thought to involve lymphoid hypertrophy in the Peyer's patches, which can act as a lead point for the telescoping of the bowel. *BCG* - The **BCG (Bacillus Calmette-Guérin) vaccine** protects against tuberculosis and is administered intradermally. - It is known for localized reactions such as **ulceration at the injection site** and potential regional lymphadenitis, but not intussusception. *Poliovirus* - **Poliovirus vaccines** (both inactivated polio vaccine (IPV) and oral polio vaccine (OPV)) are highly effective in preventing poliomyelitis. - Common side effects are usually mild, such as soreness at the injection site for IPV, with **no known association with intussusception**. *Parvovirus* - There is currently **no routine widely available parvovirus vaccine for humans**. - **Parvovirus B19 infection** in humans can cause erythema infectiosum (fifth disease) and, in some cases, hydrops fetalis or transient aplastic crisis, but it is not linked to intussusception or vaccine-related adverse events.

Q: In which of the following is immunization given after infection is started

Rabies. ***Rabies*** - Rabies vaccine is unique because it can be administered **post-exposure**, forming the basis of **post-exposure prophylaxis (PEP)**. - Due to the long incubation period of the rabies virus, PEP can be effective in preventing the disease even after exposure. *Influenza* - The influenza vaccine is given **before exposure** to prevent or lessen the severity of the flu. - It is an annual vaccine recommended for seasonal prevention and is not effective once an infection has started. *Poliomyelitis* - Polio vaccines (both inactivated and oral live-attenuated) are given **pre-exposure** to prevent infection. - They are part of routine childhood immunization schedules and are not used as treatment after infection begins. *Herpes* - There is no widely available preventative vaccine for common herpes simplex virus (HSV) infections. - Antiviral medications are used to manage outbreaks or prevent recurrence, not a post-exposure vaccine.

Q: Which of the following is used as prophylaxis in case of diphtheria:

DPT vaccine. ***DPT vaccine*** - The **DPT vaccine** (Diphtheria, Pertussis, Tetanus) provides **active immunity** against diphtheria by introducing inactivated diphtheria toxin (toxoid). - This primes the immune system to produce antibodies, offering **long-term prophylaxis** against future infections. *Erythromycin* - **Erythromycin** is an antibiotic used for the **treatment** of diphtheria, not for primary prophylaxis. - It works by inhibiting bacterial protein synthesis, but does not induce protective antibodies for long-term prevention. *Ampicillin* - **Ampicillin** is a penicillin-class antibiotic that is generally **not the drug of choice** for either prophylaxis or treatment of diphtheria. - While it has broad-spectrum activity, diphtheria treatment typically relies on antitoxin and specific macrolide antibiotics like erythromycin. *DAT* - **DAT (Diphtheria Antitoxin)** provides **passive immunity** by directly administering preformed antibodies against diphtheria toxin, used for treating active diphtheria infections or as post-exposure prophylaxis in unimmunized individuals. - It offers immediate but **short-lived protection** and is not used for routine, long-term prophylaxis.

Q: The efficiency of cold chain system for oral polio vaccine as monitored by Vaccine Vial Monitor (VVM) depends on:

Change in colour of monitor. ***Change in colour of monitor*** - The Vaccine Vial Monitor (VVM) is a label on vaccine vials that changes color progressively when exposed to heat, indicating cumulative heat exposure. - A change in the **VVM's color** signifies that the vaccine may have been exposed to temperatures that could reduce its potency and determines its usability. *Viral potency test* - A **viral potency test** directly measures the amount of live virus in a vaccine sample, which is a laboratory-based assessment and not a real-time field indicator of cold chain efficiency. - While it assesses the vaccine's actual effectiveness, it is not what the VVM monitors in the field for cold chain breaks. *Temperature indicator of the system* - A **temperature indicator** on the cold chain system itself monitors the temperature of the storage unit, not the cumulative heat exposure of individual vaccine vials. - While important for overall cold chain management, it doesn't directly indicate the heat exposure specific to a vaccine vial like a VVM does. *Change in the colour of vaccine* - A change in the **color of the vaccine** itself could indicate contamination or degradation due to various factors, not exclusively due to inadequate cold chain management as monitored by VVM. - The VVM is a separate label designed specifically to monitor heat exposure effects on the vaccine.

Q: Which of the following vaccines is most sensitive to heat?

Measles vaccine. ***Measles vaccine*** - The **measles vaccine** is a live attenuated vaccine that is the **most heat-sensitive** among commonly used vaccines. - It loses potency **rapidly** at temperatures above 8°C and is particularly vulnerable to both heat and light exposure. - Requires the **strictest cold chain maintenance** and must be protected from light at all times to maintain efficacy. *Oral Polio vaccine* - The **oral polio vaccine (OPV)** is a live attenuated vaccine that is also **heat-sensitive** and requires cold chain maintenance. - While highly heat-sensitive, it is equipped with **Vaccine Vial Monitors (VVM)** to track heat exposure, and is slightly more stable than measles vaccine. - Its efficacy declines with temperature excursions, but not as rapidly as measles vaccine. *BCG vaccine* - The **BCG vaccine**, a live attenuated vaccine against tuberculosis, has **moderate heat stability** compared to measles and OPV. - While it still requires cold chain storage, it is less sensitive to brief temperature excursions than both measles and OPV vaccines. *DPT vaccine* - The **DPT vaccine** (diphtheria, pertussis, tetanus) is an inactivated vaccine, which makes it the **most heat-stable** among these options. - It can tolerate exposure to warmer temperatures for longer periods without significant loss of potency compared to live attenuated vaccines.

Q: Number of doses of HDCV vaccine required for preexposure prophylaxis?

3. ***Correct Option: 3*** - Pre-exposure prophylaxis (PrEP) with **HDCV** (Human Diploid Cell Vaccine) typically involves a **three-dose series** administered on days 0, 7, and 21 or 28 for individuals at continuous or frequent risk of rabies exposure. - This schedule aims to establish immunity before potential exposure, providing a protective antibody response. *Incorrect Option: 5* - A five-dose regimen is typically reserved for **post-exposure prophylaxis (PEP)** in unvaccinated individuals after a rabies exposure. - This intensive schedule is designed to rapidly induce immunity when exposure is confirmed or highly suspected. *Incorrect Option: 1* - A single dose of HDCV is insufficient for establishing protective immunity against rabies, whether for pre-exposure or post-exposure prophylaxis. - A multi-dose series is required to prime the immune system and induce an adequate antibody response. *Incorrect Option: 7* - A seven-dose regimen is not a standard or recommended vaccination schedule for either pre-exposure or post-exposure prophylaxis against rabies. - Such an extended schedule would be medically unnecessary and deviate from established guidelines.

Q: National switch day for polio vaccine in India is

April 25, 2016. ***April 25, 2016*** - This date marks India's participation in the coordinated **global "switch day"** when 155 countries, including India, simultaneously transitioned from using **trivalent oral polio vaccine (tOPV)** to **bivalent oral polio vaccine (bOPV)**. - The switch was a critical step in the **polio eradication endgame strategy**, specifically targeting the withdrawal of the type 2 vaccine component due to the eradication of wild poliovirus type 2. - India successfully implemented this switch across all its immunization centers on this single day. *April 23, 2014* - This date does not correspond to the polio vaccine switch day in India. - While significant events occurred in polio eradication efforts around this time, the specific tOPV to bOPV switch was on April 25, 2016. *April 26, 2017* - This date is not the polio vaccine switch day in India. - By 2017, the tOPV-bOPV switch had already been successfully implemented globally and in India. *April 24, 2025* - This date is in the future and therefore cannot be the historical polio vaccine switch day. - There are no current plans for another vaccine switch of this magnitude for polio on this date.

Question 1

Two viral vaccines are expected to reduce the incidence of cancers. Which vaccines are these?

Accepted Answer

HPV 16/18 and hepatitis B vaccines

Answer

Measles virus and rubella virus vaccines

Answer

HAV and poliovirus vaccines

Answer

Adenovirus and mumps virus vaccines

Question 2

Vaccination causing intussusception is

Accepted Answer

Rotavirus

Answer

BCG

Answer

Poliovirus

Answer

Parvovirus

Question 3

In which of the following is immunization given after infection is started

Accepted Answer

Rabies

Answer

Influenza

Answer

Poliomyelitis

Answer

Herpes

Question 4

Which of the following is used as prophylaxis in case of diphtheria:

Accepted Answer

DPT vaccine

Answer

Erythromycin

Answer

Ampicillin

Answer

DAT

Question 5

The efficiency of cold chain system for oral polio vaccine as monitored by Vaccine Vial Monitor (VVM) depends on:

Accepted Answer

Change in colour of monitor

Answer

Viral potency test

Answer

Temperature indicator of the system

Answer

Change in the colour of vaccine

Question 6

All of the following statements about MMR vaccine are true EXCEPT:

Accepted Answer

All live vaccines without exception are contraindicated in pregnant women

Answer

MMR is a live vaccine

Answer

Adverse events from MMR vaccine include fever (usually 6-12 days following vaccination), rash in 5% of vaccinated persons, arthralgia, aseptic meningitis, lymphadenopathy

Answer

Evidence shows that aseptic meningitis is associated with all mumps vaccine strains except the Jeryl Lynn strain

Question 7

Which of the following vaccines is most sensitive to heat?

Accepted Answer

Measles vaccine

Answer

BCG vaccine

Answer

DPT vaccine

Answer

Oral Polio vaccine

Question 8

Number of doses of HDCV vaccine required for preexposure prophylaxis?

Accepted Answer

3

Answer

5

Answer

1

Answer

7

Question 9

National switch day for polio vaccine in India is

Accepted Answer

April 25, 2016

Answer

April 23, 2014

Answer

April 26, 2017

Answer

April 24, 2025

Question 10

True about polioviruses is -

Accepted Answer

Inactivated polio vaccine (IPV) is part of the routine immunization schedule for children.

Answer

Spastic paralysis

Answer

Most cases are symptomatic

Answer

Historically, intramuscular injections during the incubation period were thought to increase paralysis risk.

Immunization and Vaccine-Preventable Diseases — MCQs

Immunization and Vaccine-Preventable Diseases — MCQs

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