Self-study
The symptoms of hepatitis A appear no earlier than 60 days after a person has been infected. ██ █ ████ ██ █ █████████ █ ████████ ██ ██████ ████████ ███ ███████ ███ ██ ██████ ████████ █ ████████ ████████ ████████ ████ ██████ ████ ████ █████ ██████████ █████████ ████████ ██ █████████ ██ ███ ███████ ██ ████ ██ ███ ████ ██ ██████████ █████████ ██ ██████████ █████████ ████ ███ █████████ █ ██████
"Surprising" Phenomenon
Why did people who received the hepatitis A vaccine exhibit symptoms of hepatitis A?
Objective
A hypothesis resolving this discrepancy must reveal new information about the group who received the vaccine. It should either indicate their infection with hepatitis A prior to inoculation or distinguish between the hepatitis A virus and the symptoms it causes.
10.
Which one of the following, ██ █████ ████ █████ ███████ ███ ████████ ███████████ ██ ███ ███████████ ██████
a
The placebo did ███ ███████ ███ ████ ███████ ████ █████████ ███ ██ ███ ████████ ██ █████████ ██
This does not imply that the vaccine did produce such side effects. It refers to placebo recipients only, and does not address the discrepancy, which involves only vaccine recipients.
b
More members of ███ █████ ████ ███ ████████ ███ ███████ ██████████ █████ ████████ ██ ████████ ██ █████████ █ ████ ███ ███████ ██ ███ █████ ████ ███ ████████ ███ ████████
This is irrelevant information. There is no indication that participants self-reported their symptoms, so this difference in attribution between the groups would not have affected the study.
c
The people who ████████ ███ ███████ ████ ██ ██████ ███████ ████████ █████████ ████ ████ ███ ██████ ███ ████████ ███ ████████
This does not explain why people who received the vaccine developed hepatitis A symptoms. The discrepancy is not between the two groups, but between the vaccine's complete effectiveness and the hepatitis A symptoms among the people who received it.
d
The vaccinated people ███ █████████ ████████ ██ █████████ █ ████ ████████ ████ ███ █████████ █ █████ ██████ █████ ███████████
This resolves the apparent paradox by explaining that vaccine recipients were infected prior to inoculation. It is consistent because the author gives no information about the vaccine's effect on patients already infected with hepatitis A.
e
Of the people ███ █████████ ████████ ██ █████████ ██ █████ ███ ████████ ███ ███████ █████████ ████ ████████ ██ ████████ ████ █████ ███ ███ ████
This does not explain how vaccine recipients developed symptoms in the first place. If the vaccine is completely effective, patients who received it should not have contracted hepatitis A.