A doctor’s office has run out of the latest flu vaccine, but many patients are asking for it. One of the nurses finds some vials from last year’s batch in a refrigerator. Should they be used?

Question

A.  Yes, because the preservatives and refrigeration ensure that the vaccine is still fresh.
B.  No, because each year the technology to make a good vaccine improves.
C.  No, because each year the vaccine is made against different subtypes of the flu virus.
D.  Maybe – the vaccine should be mixed in a test tube with the virus to see if it still inactivates it.

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 the flu virus?
 
Choose Answer
· Given what you now know, what information and/or problem solving approach 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.  No, because each year the vaccine is made against different subtypes of the flu virus.

Clarify Question
· What is the key concept addressed by the question?
        o This question addresses the flu virus.
· What type of thinking is required?
        o This question is asking you to weigh and judge evidence, or evaluate, to choose the best of the possible answers.
 
Gather Content
· What do you already know about the flu virus?
        o Unlike most other viruses, the influenza virus is known for high rates of mutation and recombination.
        o Different strains of flu virus, called subtypes, differ in their protein spikes. One of these proteins, hemagglutinin (H), aids the virus in gaining access to the cell interior. The other, neuraminidase (N), helps the daughter viruses break free of the host cell after replication.
        o Parts of the H molecule contain “hotspots” with a high rate of mutation.
        o Also, viral RNA segments are readily reassorted by genetic recombination when two different subtypes simultaneously infect the same cell. This may put together novel combinations of H and N spikes unrecognizable by human antibodies specific for the old configuration.
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o Does the technology to make a good vaccine improve each year? Not really.
        o Should the vaccine be mixed in a test tube with the virus to see if it still inactivates it? No. Remember that the vaccine is a mimic of the virus that trains the immune system to recognize it. It does not directly inactivate the virus.
        o Will the preservatives and refrigeration ensure that the vaccine is still fresh? Yes, probably – but it will likely be ineffective.
        o Each year, is the vaccine made against different subtypes of the flu virus? Yes. This is why last year’s vaccine is likely to be ineffective and should not be used.
 
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?
        o The question required you to weigh and judge evidence, or evaluate, to choose the best of the possible answers.
        o Did you recognize that the flu vaccine is different every year, to match the common new subtypes?