Question 1

Which of the following best describes 'herd immunity' in the context of infectious disease control?

Accepted Answer

Protection against illness provided to a population when a pathogen cannot spread because a majority of the group are resistant to the pathogen.

Question 2

Which statement correctly differentiates inactivated vaccines from attenuated vaccines?

Accepted Answer

Inactivated vaccines are not capable of causing infection and are safe, but may not be as effective as attenuated vaccines.

Question 3

Which of the following is an example of an attenuated vaccine?

Accepted Answer

MMR shot

Question 4

What is a major risk associated with attenuated vaccines?

Accepted Answer

They can revert to a virulent form and cause disease.

Question 5

Which type of immunity is primarily produced by the Salk polio vaccine?

Accepted Answer

IgG immunity (serum immunity)

Question 6

Why might the Sabin polio vaccine be preferred in regions where polio is still endemic?

Accepted Answer

It produces IgA immunity in the gut, which is the primary site of poliovirus replication.

Question 7

Poliovirus belongs to which viral family and what is its genome type?

Accepted Answer

Picornaviridae; positive sense single-stranded RNA virus

Question 8

How is poliovirus primarily transmitted?

Accepted Answer

Oral-fecal route

Question 9

Which of the following vaccines is an example of a killed or inactivated whole agent vaccine?

Accepted Answer

Salk Polio shot

Question 10

A country is polio-free and certified by WHO. Which polio vaccine is most likely recommended for routine immunization in this country?

Accepted Answer

Salk polio vaccine (inactivated)

Question 11

Which of the following best explains why inactivated vaccines may require booster doses?

Accepted Answer

They are less likely to stimulate a strong, long-lasting immune response compared to live attenuated vaccines.

Question 12

Which of the following equations best represents the concept of herd immunity threshold ($$H) in a $$population, given the basic reproduction number $$R_0$$?

Accepted Answer

$$H = 1 - \frac{1}{R_0$}$$

Question 13

A patient receives the Sabin polio vaccine. Which immunoglobulin is most important for protection at the site of initial viral replication?

Accepted Answer

IgA

Question 14

Which of the following is a disadvantage of using attenuated vaccines?

Accepted Answer

They can pose a threat of reversion to a virulent form.

Question 15

Which of the following is NOT a characteristic of inactivated vaccines?

Accepted Answer

They can revert to a virulent form.

Question 16

Which vaccine type is most likely to produce both humoral and cell-mediated immunity?

Accepted Answer

Attenuated vaccine

Question 17

If a population has a basic reproduction number $$R_0 = 5$ for a disease, what proportion of the population must be immune to achieve herd immunity?

Accepted Answer

$$0.8$$

Question 18

Which of the following is a correct statement about the Salk and Sabin polio vaccines?

Accepted Answer

Salk is inactivated and produces serum immunity; Sabin is attenuated and produces gut immunity.

Question 19

Which of the following is a reason why the oral Sabin polio vaccine is not recommended in polio-free countries?

Accepted Answer

It can pose a threat of reversion to virulence.

Practical Applications of Immunology: Vaccines and Immunological Testing

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