Question 15, a new government policy has been developed to avoid many serious cases of influenza.
This goal will be accomplished by the annual vaccination of high-risk individuals, everyone
65 and older as well as anyone with a chronic disease that might cause them to experience
complications from the influenza virus.
Each year's vaccination will protect only against the strain of the influenza virus
deemed most likely to be prevalent that year, so every year, it will be necessary for all
high-risk individuals to receive a vaccine for a different strain of the virus.
First step argument or facts?
Clearly, we have an argument.
The conclusion is that every year, it will be necessary for all high-risk individuals
to receive a vaccine for a different strain of the virus.
How do we know that?
Well, the premise is that each year's vaccination will protect only against the strain of influenza
virus deemed most likely to be prevalent that year.
If you notice, the structure of this argument, our premise is that each year's vaccination
will protect only against the most prevalent strain of influenza virus.
And from that premise, the author concludes that high-risk individuals must receive a
vaccine for a different strain of influenza every year.
You notice that that conclusion does not follow from that premise.
Just because each year's vaccination will only protect against the most prevalent strain
of influenza, that is not sufficient to conclude that high-risk individuals must receive a
vaccine for a different strain of influenza each year.
How do we know that one strain cannot be prevalent in multiple years?
So this is clearly a flawed argument and as we proceed to the questions then, we see which
one of the following is an assumption that would allow the conclusion above to be properly
Allow the conclusion to be properly drawn, we have another strengthen with sufficient
Again, looking for the answer choice that 100% guarantees the conclusion that high-risk
individuals must receive a vaccine for a different strain of influenza each year based on the
premise that each year's vaccination will only protect against the most prevalent strain
Let's take a look at (A).
The number of individuals in the high-risk group for influenza will not significantly
change from year to year.
You notice (A) is completely irrelevant, we don't care how many people are in this high-risk
group from year to year, so (A) clearly does not even strengthen so how can it strengthen
and guarantee the conclusion?
(B), the likelihood that a serious influenza epidemic will occur varies from year to year.
Again, completely irrelevant.
That does nothing to our argument.
It definitely does not guarantee the conclusion, so (B) is eliminated.
(C), no vaccine for the influenza virus protects against more than one strain of that virus.
(C) is a popular answer choice among students because (C) does strengthen.
It's basically saying that every vaccine only protects against one strain.
That seems to strengthen the argument because you cannot get a vaccine that protects you
against 10 different strains of influenza but you notice, it does not guarantee the
conclusion that a new vaccine is needed every year for high-risk individuals because even
if every vaccine only protects against one strain of influenza, how do we know that we
cannot have a strain that was prevalent in one year also be prevalent in another year?
(C) doesn't address that problem with this argument so (C) would be eliminated.
Which brings me to (D).
Each year, the strain of influenza virus deemed most likely to be prevalent will be one that
had not previously been deemed most likely to be prevalent.
And you notice, (D) closes the gap by telling us if you're deemed to be most prevalent in
one year, you are not going to be deemed to be prevalent in any other year and that would
guarantee the conclusion that high-risk individuals must receive a vaccine for a different strain
of influenza each year, so (D) would be the correct answer, again, 100% guarantees the
conclusion in the passage.
Lastly, just to make sure you're checking (E), each year's vaccine will have fewer side
effects than the vaccine of the previous year since the technology for making vaccines will
Again, we are not talking about side effects.
(E) is completely irrelevant so (E) is eliminated.