Every year a new version of the flu vaccine is made using a mixture of strains. The strains are chosen based on surveillance and analysis by experts from the FDA, WHO, and CDC. For other diseases however, such as varicella (chickenpox), the same vaccine is used continually and repeated vaccinations are not necessary. What do you conclude is the important difference between the influenza virus and the varicella zoster virus with regards to vaccinations?

Question

Different viruses have different properties that affect how the immune system responds to them, and consequently how vaccines must be developed.

A.  Influenza virus is transmitted through aerosol droplets in the air, while varicella can be transmitted via skin secretions.
B.  Varicella is attacked by the innate immune system, while influenza is attacked by the acquired immune system.
C.  Influenza virus has a much higher mutation rate than varicella, leading to frequent antigen changes in the coat proteins.
D.  Influenza envelope proteins are bound by IgM, while varicella envelope proteins are bound by IgG.


Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?
 
Gather Content
What do you already know about varicella zoster and influenza? What other information is related to the question?
 
Choose Answer
Given what you now know, what information is most likely to produce the correct answer?

Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

C.  Influenza virus has a much higher mutation rate than varicella, leading to frequent antigen changes in the coat proteins.


Clarify Question
What is the key concept addressed by the question?
        · This question is asking you to differentiate between the influenza and varicella zoster vaccinations.
What type of thinking is required?
        · Apply level:
            o You are being asked to take what you already know and use, or apply, it to the reason for different vaccination schedules for different viruses.
 
Gather Content
What do you already know about varicella zoster and influenza? What other information is related to the question?
        · Vaccinations are designed to stimulate antibodies against specific antigens.
        · If antigens change through mutation, antibodies that were produced by a previous vaccination may not recognize the newly mutated virus.
        · The mutation rate of varicella zoster is relatively low.
        · The mutation rate of influenza is high.
 
Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Difference is transmission of a virus would not influence the internal efficacy of a vaccine.
        · Both viruses are attacked by antibodies that are the result of adaptive immunity.
        · Influenza has a much higher mutation rate, and consequently new vaccines must be developed every year.

Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · Apply level:
            o Answering this question correctly depended on your ability to use varicella zoster and influenza viruses in a new situation. If you got an incorrect answer, did you remember that influenza mutates reapidly, or that varicella zoster has a much lower mutation rate? Did you have trouble extending the nature of these viruses to determine the correct answer?