Which metric tends to be higher during epidemics such as influenza?

During epidemics such as influenza, a significant increase is observed in the number of new cases of the disease within a specific time period. This metric is known as incidence, which reflects the rate of new infections occurring. During an epidemic, the rapid spread of the virus among the population leads to a surge in new cases, thereby resulting in higher incidence rates.

In contrast, prevalence, which measures the total number of existing cases (both new and pre-existing) at a given time, may also be affected but does not exclusively indicate the rapid increase seen with new infections during an outbreak. While treatment rates can increase because more individuals seek care during an outbreak, this doesn't specifically correlate to the metric in question. Similarly, recurrence rates relate to individuals who previously experienced the illness and have a subsequent return of the disease, which is not the primary focus during an epidemic situation. Hence, the distinguishing feature of an epidemic—marked by a rapid outbreak of new cases—underlines why incidence is the metric that tends to be higher during such times.