Question 1

Which of the following best describes the mechanism by which mRNA vaccines, such as those for COVID-19, induce immunity?

Accepted Answer

They deliver mRNA encoding a viral protein, which is translated by host cells, leading to an immune response.

Question 2

A patient receives a vaccine containing an inactivated toxin. Which type of vaccine did they receive, and what is a classic example?

Accepted Answer

Toxoid vaccine; Tetanus vaccine

Question 3

Which of the following equations is used to calculate the herd immunity threshold ($$HIT) $$for a given infectious disease?

Accepted Answer

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

Question 4

Why are live attenuated vaccines generally not recommended for immunocompromised patients?

Accepted Answer

They may revert to a pathogenic form and cause disease.

Question 5

A laboratory is using a plaque reduction neutralization test (PRNT) to assess a patient's serum for antibodies against a virus. Which result indicates the presence of neutralizing antibodies?

Accepted Answer

There is a significant reduction in the number of plaques compared to the control.

Question 6

Which of the following best explains why herd immunity is critical for protecting vulnerable populations?

Accepted Answer

It reduces the number of susceptible hosts, limiting pathogen transmission.

Question 7

Which of the following is a key advantage of subunit vaccines over whole-agent inactivated vaccines?

Accepted Answer

They are less likely to cause adverse reactions because they contain only specific antigens.

Question 8

A patient receives antibodies against a toxin after a snake bite. Which type of immunity is this, and is it natural or artificial?

Accepted Answer

Artificially acquired passive immunity

Question 9

Which of the following statements about the polymerase chain reaction (PCR) is correct?

Accepted Answer

PCR uses cycles of heating and cooling to exponentially amplify DNA.

Question 10

Which of the following best describes the function of CRISPR-Cas9 in gene editing?

Accepted Answer

It uses a guide RNA to target and cut specific DNA sequences, allowing insertion of new genetic material.

Question 11

A child receives the MMR vaccine, which contains live, weakened viruses. What is the main benefit of this type of vaccine?

Accepted Answer

It induces a strong, long-lasting immune response with immunological memory.

Question 12

Which of the following is a potential drawback of inactivated vaccines compared to live attenuated vaccines?

Accepted Answer

They often require booster doses to maintain immunity.

Question 13

Which of the following best explains why the MMR/autism study published in 1998 was later retracted?

Accepted Answer

It was found to be based on fraudulent data and had major conflicts of interest.

Question 14

Which of the following is a correct pairing of vaccine type and example?

Accepted Answer

Conjugate vaccine – Pneumococcal vaccine

Question 15

A patient’s blood sample is tested using a direct ELISA. What is being detected in this assay?

Accepted Answer

Antigens from the patient’s sample using an enzyme-linked detection antibody

Question 16

Which of the following best describes the role of adjuvants in subunit vaccines?

Accepted Answer

They enhance the immune response by stimulating cytokine release and antigen uptake.

Question 17

Which of the following scenarios is an example of naturally acquired passive immunity?

Accepted Answer

A newborn receives antibodies through the placenta from the mother.

Question 18

Which of the following is a key feature of recombinant vector vaccines?

Accepted Answer

They use a genetically modified carrier virus to deliver pathogen genes.

Question 19

A patient with leukemia and HIV receives a bone marrow transplant from a donor with two copies of the CCR5-Δ32 allele. What is the expected outcome regarding HIV infection?

Accepted Answer

The patient’s cells will lack CCR5 receptors, preventing HIV from entering and replicating.

Biomedical Applications: Vaccines, Diagnostics, Therapeutics, and Molecular Methods

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