Question 1

Which of the following best describes an attenuated vaccine, and what is a major risk associated with its use?

Accepted Answer

A vaccine containing weakened live pathogens; risk of reversion to pathogenic form.

Question 2

Why is herd immunity important in the context of vaccination programs?

Accepted Answer

It prevents the spread of disease by reducing the number of susceptible hosts in a population.

Question 3

Which type of serological test is depicted in the image showing a visible ring forming at the interface between antigen and antibody solutions in a test tube?

Accepted Answer

Precipitation test

Question 4

A patient receives a blood transfusion and develops hemolysis due to the presence of anti-A antibodies in their plasma. What is the most likely blood type of the donor and the recipient?

Accepted Answer

Donor: Type A, Recipient: Type B

Question 5

Which of the following best explains why polysaccharide vaccines are less effective in children under 2 years old?

Accepted Answer

They elicit only IgM responses and do not generate immunologic memory.

Question 6

What is the primary mechanism by which neutralization tests detect the presence of antibodies in a patient’s serum?

Accepted Answer

Antibodies bind to and inactivate toxins or viruses, preventing their effect on cells.

Question 7

A child develops a rash and fever after exposure to poison ivy. Which type of hypersensitivity reaction is this, and what is the main immune mechanism involved?

Accepted Answer

Type IV (Delayed cell-mediated); T-cell mediated immune response

Question 8

Which of the following statements about the hygiene hypothesis is correct?

Accepted Answer

Increased exposure to microbes in early life may reduce the risk of allergies and autoimmune diseases.

Question 9

In the ELISA test, what is the role of the enzyme-linked antibody?

Accepted Answer

It binds to the antigen and produces a visible color change when substrate is added.

Question 10

Which of the following is a major reason why the MMR vaccine is highly effective at preventing measles outbreaks?

Accepted Answer

It is a live attenuated vaccine that induces both cellular and humoral immunity.

Question 11

A patient with Crohn’s disease is treated with 'poop pills' as shown in the image. What is the scientific basis for this therapy?

Accepted Answer

Restoration of normal gut microbiota to correct dysbiosis.

Question 12

Which of the following best describes the mechanism of action for a conjugated vaccine?

Accepted Answer

A polysaccharide antigen is linked to a protein toxoid to enhance immunogenicity.

Question 13

Which of the following is a characteristic of Type III hypersensitivity reactions?

Accepted Answer

Formation of immune complexes that deposit in tissues, causing inflammation.

Question 14

A newborn develops hemolytic disease due to Rh incompatibility. Which maternal and fetal blood types are most likely involved?

Accepted Answer

Mother: Rh-, Fetus: Rh+

Question 15

Which of the following is a correct statement about adjuvants in vaccines?

Accepted Answer

They enhance the immune response to the antigen in the vaccine.

Question 16

Which of the following best explains the decline in MMR vaccination rates among Somali children in Minnesota, as shown in the graph?

Accepted Answer

Concerns about a fraudulent link between MMR vaccine and autism led to decreased vaccination rates.

Question 17

Which of the following is an example of artificial passive immunity?

Accepted Answer

Administration of immune globulin (IgG) after exposure to hepatitis B.

Question 18

Which of the following is a key difference between direct and indirect agglutination tests?

Accepted Answer

Direct tests use whole cells as antigens, while indirect tests use antigens or antibodies attached to particles.

Question 19

Which of the following best describes the mechanism of rheumatoid arthritis?

Accepted Answer

Autoantibodies target proteins in the synovial membrane, leading to chronic inflammation and joint damage.

Chapter 18-19_Hypersensitivities & Vaccines

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