medium · SAT Reading & Writing

Text 1: Epidemiologists use 'herd immunity' thresholds to determine what percentage of a population must be vaccinated to stop the spread of a disease. For highly contagious viruses like measles, the threshold is estimated at 95%, meaning that below this level, outbreaks are essentially inevitable. Text 2: The 95% threshold assumes a 'homogeneously mixing' population, where everyone has an equal chance of meeting everyone else. In reality, populations are clustered. If vaccination rates are 98% in most areas but only 70% in a few tight-knit communities, outbreaks can still occur even if the national average is well above the threshold.

Based on the texts, how would the author of Text 2 most likely respond to the 'threshold' described in Text 1?

By arguing that a single national average may fail to account for local variations in vaccination coverage.
By noting that the first successful vaccine was developed for smallpox in the late eighteenth century.
By claiming that vaccines have little real effect on outbreaks and that thresholds should be abandoned.
By insisting that 100% of the population must be vaccinated everywhere before any outbreak can be prevented.

Based on the texts, how would the author of Text 2 most likely respond to the 'threshold' described in Text 1?

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