Certification Board of Infection Control and Epidemiology (CBIC) Practice Exam 2025 – The All-in-One Guide for Exam Success

The indication of "significant human-to-human transmission" according to the WHO phases specifically points to "efficient/sustained human-to-human transmission." This reflects a situation where the pathogen can easily spread from one human to another in a way that maintains the infection within the population.

This phase is crucial for public health responses as it necessitates urgent intervention measures to control the outbreak. It typically means that the disease can be transmitted effectively enough to cause a widespread outbreak, demonstrating that transmission factors—like the pathogen's ability to survive outside the host, modes of transmission, and the population's susceptibility—are present.

In contrast, the other choices reflect varying degrees of human transmission that do not signify the same level of urgency or potential for a sustained outbreak. For instance, "high risk of cases" lacks specificity about transmission dynamics, while "some human-to-human transmission" implies limited or intermittent spread that may not be capable of sustaining an outbreak. "No human-to-human transmission" clearly indicates that the disease does not spread between individuals, thereby presenting no concern for human transmission. Thus, highlighting efficient and sustained human-to-human transmission is critical for understanding the severe potential impact of an outbreak and the necessary public health actions required.