Vaccines Practice Questions
20 free Vaccines practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which of the following describes the principle of 'memory' in the context of vaccination?
- A The ability of vaccine-derived antibodies to persist in the bloodstream for many years without decay
- B The production of memory B and T cells that rapidly recognize the same pathogen on re-exposure
- C The immediate generation of high-titre antibodies upon receiving the very first vaccine dose
- D The physical scarring and local tissue reaction that remains at the injection site
Correct answer: The production of memory B and T cells that rapidly recognize the same pathogen on re-exposure
Vaccines generate long-lived memory B and T cells after the initial immune response. On subsequent exposure to the same pathogen, these memory cells rapidly proliferate and produce large quantities of specific antibodies, providing fast and effective protection.
The Hepatitis B vaccine currently in use is produced using which of the following?
- A Live attenuated viral strain
- B Formalin-inactivated whole virus
- C Yeast (Recombinant DNA technology)
- D Purified venom protein extract
Correct answer: Yeast (Recombinant DNA technology)
The Hepatitis B vaccine is a second-generation subunit vaccine produced via recombinant DNA technology. The gene encoding the viral surface antigen (HBsAg) is expressed in Saccharomyces cerevisiae (yeast), which then produces the antigenic protein in large quantities.
When a person is bitten by a poisonous snake, they are given pre-formed antibodies. This type of immunization is called:
- A Active immunization
- B Passive immunization
- C Natural auto-immunization
- D Innate immunization
Correct answer: Passive immunization
Passive immunization involves the direct injection of pre-formed antibodies (antitoxins or antivenom) to provide immediate protection. It is used in snake bite cases because the body's own immune response would be too slow to prevent serious harm.
Which of the following is an example of a 'First Generation' vaccine?
- A Oral Polio Vaccine (Sabin)
- B Hepatitis B vaccine
- C DNA vaccines
- D Synthetic peptide vaccines
Correct answer: Oral Polio Vaccine (Sabin)
First-generation vaccines are prepared from whole microorganisms, either live-attenuated or killed. The Oral Polio Vaccine (OPV) consists of live-attenuated virus strains.
The BCG vaccine provides protection against which of the following diseases?
- A Cholera disease
- B Tuberculosis
- C Diphtheria disease
- D Smallpox infection
Correct answer: Tuberculosis
The BCG (Bacillus Calmette-Guérin) vaccine protects against tuberculosis. It is a live-attenuated vaccine derived from a weakened strain of Mycobacterium bovis and is particularly effective in preventing severe forms of TB in children.
Which biological molecule is typically used as a 'toxoid' in vaccines for diseases like Tetanus?
- A Inactivated viral RNA
- B Modified bacterial polysaccharides
- C Inactivated bacterial exotoxins
- D Purified viral proteins
Correct answer: Inactivated bacterial exotoxins
Toxoid vaccines use bacterial toxins that have been treated (usually with formalin) to destroy their toxicity while preserving their immunogenicity. This allows the body to form antibodies against the toxin itself.
What is the primary objective of 'Active Immunization'?
- A To provide immediate but short-lived protection through externally supplied antibodies
- B To stimulate the immune system to produce its own antibodies and memory cells
- C To treat a patient already suffering from an established chronic infectious disease
- D To suppress immune activity during organ transplantation and prevent rejection
Correct answer: To stimulate the immune system to produce its own antibodies and memory cells
Active immunization involves introducing an antigen into the body to stimulate the natural immune response. This leads to the production of specific antibodies and the formation of memory B and T cells, conferring long-term protection against future infections.
The DPT vaccine is a 'triple vaccine' that provides immunity against:
- A Diarrhea, Polio, and Typhoid
- B Diphtheria, Pertussis, and Tetanus
- C Dengue, Pneumonia, and Tuberculosis
- D Diphtheria, Polio, and Tetanus
Correct answer: Diphtheria, Pertussis, and Tetanus
DPT stands for Diphtheria, Pertussis (whooping cough), and Tetanus. It is a combination vaccine frequently administered to infants and children.
In recombinant DNA technology for vaccine production, the gene for the antigen is often inserted into:
- A Human red blood cells
- B Naked DNA injected into bloodstream
- C Bacteria or yeast host cells
- D The patient's own nerve cells
Correct answer: Bacteria or yeast host cells
In recombinant DNA technology for vaccine production, the antigen-coding gene is inserted into bacteria (e.g., E. coli) or yeast (e.g., Saccharomyces cerevisiae), which act as host organisms to produce large quantities of the target protein.
Which type of vaccine carries the lowest risk of causing the disease it is meant to prevent, even in immunocompromised individuals?
- A Live-attenuated viral vaccine
- B Inactivated/Killed vaccine
- C Sabin oral polio vaccine
- D MMR measles-mumps-rubella vaccine
Correct answer: Inactivated/Killed vaccine
Inactivated (killed) vaccines use pathogens that have been completely killed by heat or chemicals. Since the pathogen cannot replicate, there is zero risk of reversion to a virulent form, making them safe even for immunocompromised individuals.
The use of vaccines has successfully eradicated which of the following diseases globally?
- A Polio disease
- B Smallpox
- C Malaria fever
- D AIDS virus
Correct answer: Smallpox
Smallpox is the only human infectious disease to have been completely eradicated worldwide through a global vaccination campaign led by the WHO. The last naturally occurring case was recorded in Somalia in 1977.
Passive immunization is NOT preferred for which of the following scenarios?
- A Treatment of a snake bite
- B Providing immediate protection against Tetanus after a deep wound
- C Long-term community-wide disease prevention
- D Treatment of Rabies after a dog bite
Correct answer: Long-term community-wide disease prevention
Passive immunization provides immediate but temporary protection because the injected antibodies eventually degrade. It is not suitable for long-term prevention, which requires the development of memory cells through active immunization.
Which of the following is a characteristic of 'Third Generation' vaccines?
- A They use whole killed pathogens
- B They consist of pure DNA (DNA vaccines)
- C They use weakened live pathogens
- D They are only administered via the oral route
Correct answer: They consist of pure DNA (DNA vaccines)
Third-generation vaccines (DNA vaccines) involve injecting a plasmid carrying the gene for the pathogen's antigen directly into the host. The host's cells then express the antigen, triggering both humoral and cell-mediated immune responses — a significant advantage over earlier vaccine generations.
Which immunoglobulin is primarily associated with the secondary immune response triggered by a booster dose of a vaccine?
- A IgE
- B IgM
- C IgG
- D IgD
Correct answer: IgG
While IgM is the first antibody produced during the primary response, IgG is the predominant antibody in the secondary (anamnestic) response. IgG provides more effective and long-lasting immunity.
The term 'Attenuated' in vaccine science refers to:
- A Increasing the virulence of a pathogen to enhance immune response
- B Weakening a pathogen so it replicates without causing disease
- C Killing the pathogen completely using ultraviolet radiation
- D Extracting only the surface proteins of the pathogen
Correct answer: Weakening a pathogen so it replicates without causing disease
Attenuation is the process of weakening a pathogen (usually by passing it through different hosts or cell cultures). The attenuated pathogen is still 'alive' and can replicate to induce an immune response without causing the actual disease.
ATS (Anti-Tetanus Serum) injection provides which type of immunity?
- A Natural active immunity
- B Artificial active immunity
- C Artificial passive immunity
- D Natural passive immunity
Correct answer: Artificial passive immunity
ATS contains pre-formed antibodies against the tetanus toxin. Because these antibodies are produced in another organism and then injected into a human, it is classified as artificial passive immunity.
Which vaccine is typically administered to prevent 'Whooping Cough'?
- A OPV (oral polio vaccine)
- B Pertussis vaccine (DPT/DTaP)
- C MMR (measles-mumps-rubella)
- D Varicella-zoster vaccine
Correct answer: Pertussis vaccine (DPT/DTaP)
Pertussis is the clinical name for whooping cough. The pertussis vaccine (usually given as part of the DPT or DTaP combination) protects against the bacterium Bordetella pertussis.
The quick response of the immune system upon a second encounter with an antigen is due to:
- A Phagocytes
- B Inflammatory response
- C Memory cells
- D Interferons
Correct answer: Memory cells
Memory B and T cells 'remember' the specific antigen from the first exposure. When the same antigen enters the body again, these cells proliferate and differentiate rapidly to eliminate the threat before symptoms occur.
MMR vaccine provides protection against which set of diseases?
- A Malaria, Measles, Rubella
- B Measles, Mumps, Rubella
- C Mumps, Meningitis, Rabies
- D Measles, Mumps, Rhinovirus
Correct answer: Measles, Mumps, Rubella
The MMR vaccine is a trivalent vaccine that protects against three viral diseases: Measles, Mumps, and Rubella (German measles). It is generally administered in two doses during childhood.
What happens when a 'killed' vaccine is injected into the body?
- A The pathogen begins multiplying inside the liver cells
- B The immune system detects surface antigens and produces antibodies
- C The pathogen integrates its DNA into the host cell genome
- D No immune response occurs because the pathogen is already dead
Correct answer: The immune system detects surface antigens and produces antibodies
Even though the pathogen is killed and cannot replicate, its structural proteins (antigens) remain intact. The immune system recognizes these foreign proteins and mounts a primary immune response, creating memory for future protection.