ParadoxDiff: Medium
Logic Breakdown
Passage Summary: A vaccine is supposedly perfect at stopping a virus, yet during a trial, some people who were vaccinated still got sick.
Reasoning: Hepatitis A symptoms take at least 60 days to appear; a vaccine trial resulted in symptoms for both the vaccinated and placebo groups; yet the vaccine is claimed to be 100% effective at preventing infection.
Analysis: The paradox here is the clash between 'perfect effectiveness' and 'vaccinated people showing symptoms.' Since the vaccine prevents *infection* but symptoms take 60 days to show up, we have a timing issue. If someone was already infected before they got the shot, the vaccine wouldn't be able to stop a process that had already started. Look for an answer that suggests the subjects were exposed to the virus shortly before the study began.
Reasoning: Hepatitis A symptoms take at least 60 days to appear; a vaccine trial resulted in symptoms for both the vaccinated and placebo groups; yet the vaccine is claimed to be 100% effective at preventing infection.
Analysis: The paradox here is the clash between 'perfect effectiveness' and 'vaccinated people showing symptoms.' Since the vaccine prevents *infection* but symptoms take 60 days to show up, we have a timing issue. If someone was already infected before they got the shot, the vaccine wouldn't be able to stop a process that had already started. Look for an answer that suggests the subjects were exposed to the virus shortly before the study began.
Passage Stimulus
Passage Redacted
Unlock Full Passage10.Which one of the following, if true, most helps resolve the apparent discrepancy in the information above?
Correct Answer
D
D resolves the discrepancy: vaccinated people who showed symptoms had been infected before receiving the vaccine. Since symptoms emerge 60+ days after infection, those infections would manifest later even if the vaccine subsequently prevented any new infections. Thus, the vaccine can still be completely effective at preventing infection during the test period.
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