Q: Which equation best represents the calculation of sensitivity in a diagnostic test?

$$ \text{Sensitivity} = \frac{\text{True Positives}}{\text{True Positives} + \text{False Negatives}} $$

Question 1

Which of the following best describes the principle behind herd immunity?

Accepted Answer

Immunity in most of the population reduces the likelihood of disease outbreaks because there are fewer susceptible individuals.

Question 2

Which type of vaccine is most likely to confer lifelong immunity with only one or two doses, and why?

Accepted Answer

Live attenuated vaccine, because it closely mimics a natural infection and stimulates both cellular and humoral immunity.

Question 3

A patient with a compromised immune system should avoid which type of vaccine?

Accepted Answer

Live attenuated vaccine

Question 4

Which of the following statements about adjuvants is correct?

Accepted Answer

Adjuvants are chemical additives that enhance the innate immune response to a vaccine.

Question 5

Which equation best represents the calculation of sensitivity in a diagnostic test?

Accepted Answer

$$ 	ext{Sensitivity} = \frac{	ext{True Positives}}{	ext{True Positives} + 	ext{False Negatives}} $$

Question 6

Which of the following best explains why booster doses are required for inactivated killed vaccines?

Accepted Answer

They induce mostly humoral immunity and do not provide long-lasting cellular immunity.

Question 7

A conjugated vaccine is most useful for which population and why?

Accepted Answer

Young children, because their immune systems respond poorly to capsular polysaccharides alone.

Question 8

Which of the following is a key advantage of monoclonal antibodies (Mabs) over conventional antibody production?

Accepted Answer

Mabs are uniform, highly specific, and can be produced in large quantities.

Question 9

Which of the following best describes the difference between direct and indirect agglutination tests?

Accepted Answer

Direct agglutination detects antibodies against large cellular antigens, while indirect agglutination uses particles coated with antigens or antibodies.

Question 10

Which of the following is true regarding the ELISA technique?

Accepted Answer

Direct ELISA detects antigens using a single antibody, while indirect ELISA detects antibodies using two antibodies.

Question 11

A patient’s serum is tested for antibodies to a virus using a viral hemagglutination inhibition test. Which result indicates the presence of antibodies?

Accepted Answer

No hemagglutination occurs because antibodies neutralize the virus.

Question 12

Which of the following best describes the function of a toxoid vaccine?

Accepted Answer

It contains inactivated toxins to stimulate immunity against the harmful substances produced by bacteria.

Question 13

Which of the following is a real-world application of monoclonal antibodies in therapy?

Accepted Answer

Neutralizing tumor necrosis factor (TNF) in rheumatoid arthritis patients.

Question 14

Which of the following best explains the difference between precipitation and agglutination reactions?

Accepted Answer

Precipitation involves soluble antigens forming lattices with antibodies, while agglutination involves particulate antigens forming visible aggregates.

Question 15

Which of the following best describes the process of Western blotting?

Accepted Answer

Proteins are separated by electrophoresis, transferred to a membrane, and detected using specific antibodies.

Question 16

Which of the following is a key feature of nucleic acid (DNA) vaccines?

Accepted Answer

Injected naked DNA produces the protein antigen, stimulating both humoral and cellular immunity.

Question 17

Which of the following best describes the role of anti-human immune serum globulin (anti-HISG) in indirect fluorescent-antibody tests?

Accepted Answer

It binds to any human antibody present, allowing detection of specific antibodies in patient serum.

Question 18

Which of the following is a reason why subunit vaccines are considered safer than live attenuated vaccines?

Accepted Answer

They contain only antigenic fragments, reducing the risk of causing disease.

Question 19

Which of the following best explains why specificity is important in a diagnostic test?

Accepted Answer

It ensures that true negatives are not counted as positives, minimizing false positives.

Practical Applications of Immunology: Vaccines and Diagnostic Immunology

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