Logical Reasoning

PT129 · S3 · Q11 Many vaccines create immunity

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

Many vaccines create immunity to viral diseases by introducing a certain portion of the disease-causing virus's outer coating into the body.

Claim

We can make a vaccine that will produce permanent immunity to hepatitis E.

Evidence

A suitable portion of hepatitis E has been isolated, that will stimulate antibody production. People who take the vaccine will produce antibodies that would recognize hepatitis E and and kill it if the person ever encountered the actual hepatitis E virus.

Evaluation

It seems like a pretty reasonable claim, given what we're told about how vaccines work. However, the claim is strongly worded. A "permanent" immunity? Nothing in the evidence talked about permanent immunity.

In order to fight this conclusion, we need an idea that prevents the next part of the plan from being carried out (maybe we've isolated the part of hepatitis E, but we don't have a good way to introduce it into a person's body), or an idea that shows why even if we achieved immunity for a while, it wouldn't be permanent (maybe hepatitis E mutates and a newer version wouldn't be killed by the old hepatitis E antibodies).

Goal

They're NOT gonna be able to produce a permanent-immunity vaccine because ... [answer choice]

11.

Which one of the following, if true, most strongly counters the doctors' claim?

  1. Correct

    Most of the people who

    Why this is right

    This answer is tough to love at first, because it's not explaining to us why the vaccine would fail to create a permanent immunity, but it definitely serves as evidence against the notion of permanent immunity. All vaccines do is expose us to a virus, safely, so that we can make antibodies that will supposedly protect us later. If most of the people getting hepatitis E had previous exposure to the virus but still ended up getting it, then what help would the hepatitis E vaccine have been? If their bodies didn't create permanent immunity antibodies from being exposed to the disease during childhood, then why would we think that the hepatitis E vaccine would be any more successful in prompting their bodies to create permanent immunity antibodies?

    Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

    77% picked this

  2. Some laboratory animals exposed to

    Too Weak / Opposite

    It would be very unusual for the correct answer to be as weak as "some". But this one even seems to go in the wrong direction, since it sounds like no matter what strain of hepatitis E the vaccine contains, it may have the promise to inoculate us against all strains of it.

    6% picked this

  3. Researchers developed a successful vaccine

    Opposite

    This strengthens the author's claim by providing a relevantly similar example in which something similar to her claim occurred.

    2% picked this

  4. The virus that causes hepatitis

    Irrelevant Distinction

    This doesn't affect our impression of the vaccine at all. It's just saying a pretty self-justifying truism that "in areas where the virus is very common, the number of people exposed to the virus is likely to be high".

    8% picked this

  5. Many children who are exposed

    Opposite

    This strengthens the idea that early exposure leads to immunity later.

    7% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free