#11 - Many vaccines create immunity to viral diseases by

[Rita]

Hi,

I don't understand why option A counters the doctors' claim. Regardless of when most people now contract Hep E, if the doctors successfully produced a vaccine they could immunize children now, and therefore future young adults would be immune at the time they would otherwise have contracted the disease, making the claim true.

Is the idea that Hep E is unusual in that vaccines just don't work for it, because if they did, those children who were exposed in childhood would already be immune? I see that the other answers also don't weaken the claim, but still can't determine why A does.

Thanks!
Rita

[Adam Tyson]

Thanks for the question, Rita! The issue here is the whole "exposure/subsequent recognition" idea behind vaccines. We're told that vaccines work by first exposing us to a harmless part of the virus, stimulating the creation of antibodies, so that if we ever later on get exposed to the real thing our body will recognize it and be equipped to fight it off.

If answer A is true, then it means that at least for Hep E, early exposure did NOT result in later recognition and the ability to fight it off. Young adults who were exposed as kids got the disease later in life after another exposure. That suggests that, at least for Hep E, vaccines may not work. That's why it weakens the doctors' argument.

Be careful when dealing with weaken questions not to get caught up looking for something that totally destroys the argument. Weaken doesn't have to be much damage, just some damage. I smashed my finger in a doorframe last night, and my ability to grip and type today is weakened. Don't write my hand off entirely, though! It's too soon to be talking about amputation! My finger and hand haven't been destroyed, but they have been weakened, at least for now.

A may not disprove the argument, because a working vaccine may still be possible, but it does cast at least some doubt on the claims, and that's enough for our LSAT purposes.

I hope that helps!

[k100]

I managed to get the right answer, unfortunately after realizing my prephrases were unhelpful. Before I went through the answer choices, these were my thoughts:

1) Perhaps hep E is unrecognizable by antibodies in some way
2) Many vaccines create immunity until a new dose of the vaccine is needed, meaning that a hep E vaccine might not be permanent

How could I have improved my prephrases?

I was also wondering if it's possible I could be better off without prephrasing strengthen/weaken questions, because the answer choices are usually prefaced by "if true." Doesn't this present way too many options to consider in my prephrase? Any tips are appreciated!

[Rachael Wilkenfeld]

Hi k100,

Your first prephrase here conflicts a bit with the information in the stimulus, which may be what caused you some difficulties. Our stimulus tells us that the scientists were able to isolate the portion of hep E which stimulates the production of antibodies that will subsequently recognize it. So it can't be the case that hep E is unrecognizable by antibodies.

Your second prephrase/thought was spot on. In weaken questions, I often try to look for the "jump" in the conclusion. Where does the author conclude something that wasn't supported? What does that mean for what the weaken answer will probably do? I don't often have a very specific prephrase on weaken questions, but I have a general idea of where the answer will probably focus. In this case, I immediately noted the huge jump from immunity in the premises, to permanent immunity in the conclusion. That's a huge leap to make, and as you note, not necessarily something that happens with vaccines in real life. We sometimes need a good booster.

In general, in strengthen or weaken questions, you should not be prephrasing a specific fact that you think would strengthen or weaken the argument. You want to look for the part of the argument to exploit or help. That's naturally going to at least involve the conclusion, but often you can get a bit more specific. For example, here we both noticed that the idea of "permanent" was likely to be an area to exploit. If you see a causal argument, that will be a focus in either strengthen or weaken.

Hope that helps
Rachael

[KG!]

Under timed conditions I originally chose A and then under review I decided to go with D. I definitely see why A is the correct answer its just my periphrases for weakening don't always lead me to the correct answer choice.


For example, I thought to myself "find the answer choice that shows that when the vaccine is created it is not likely to produce permanent immunity to that disease."
wrong prephrase or right prephrase? could this have led to the correct answer choice. It seems like it did originally or maybe I was lucky.

Also based on the PowerScore bibles what type of answer choice is answer A since its a cause and effect stimulus.

[Littletiger1888]

Hi - I thought there's a flaw with answer A. What if those "people who contracted Hep.E as young adults who contracted it as children" NEVER got vaccinated? Then answer A does not weaken the stimuli. Am I right?

[Frank Peter]

Hi Littletiger,

I think whether they got vaccinated or not isn't the most important issue here. The central claim that we are calling into question is the assertion "Exposure to that part of a virus is as effective as exposure to the whole virus in stimulating production of antibodies that will subsequently recognize and kill the whole virus."

(A) calls into question whether this would be the case with hepatitis E. If the people who are contracting it have previously been exposed to the virus, then it sounds like that the body doesn't recognize and kill the virus the same way that it might with other viruses.

[Frank Peter]

Hi KG,

I think your prephrase sounds good; in the case of answer choice (A), we have a group that was previously exposed to the virus and then contracts it again, so it is conceivable that the vaccine wouldn't lead to permanent immunity.

The cause and effect relationship in the stimulus could be understood as: exposure immunity

In the case of the group in answer choice (A) we have: exposure ~immunity

In other words, answer choice (A) is the cause without the effect.