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Three times a week, the Perry County Health Department updates the community on the number of new COVD-19 cases that have been reported, along with other statistics including recoveries, deaths, age of infected persons and hospitalizations.
In addition, these regular updates include a graph displaying the daily changes in the number of cases of the novel coronavirus in the county, along with another chart displaying a "COVID-19 Alert Level," consisting of an arc divided into five color-coded categories ranging from "very low," or green, to "high," which is red, and a pointer.
Since July 20, that pointer has been firmly fixed in the middle, pointing to the yellow slice marked "Moderate."
What exactly does that mean? Does the needle creep higher as the number of cases increase?
Health department assistant director and epidemiologist Liz House says the graph is meant to show the risk of a person possibly getting infected and is not directly related to the number of positive cases in the county.
“With our risk level, there is not a set algorithm where if certain numbers are more than x, then we are going to change the color one way or another," House said. "We consider several recommended key data indicators; the majority of which show a trend in the community one way or another."
Those trends, she said, can sometimes be hard to see, especially when compared to some of the larger communities to the north and south.
"Sometimes, with the small numbers seen in Perry County has compared to larger metropolitan areas, some statistics don’t show a trend one way or another," House said. "Therefore, all are taken into consideration when assessing overall community risk."
In addition to tracking those trends, House said contact tracing — or determining who an how many people and infected person has been in contact with — plays a definite role in determining risk level.
"Also taken into consideration are the number of new cases who are household contacts to positive cases who have tested positive or cases associated with ongoing, isolated, outbreaks within an organization because these circumstances can result in inflated numbers of active or new cases that may not be indicative of larger community spread," House said.
Other factors include the epidemiological curve, which is a visual display of illness onset among cases associated with an outbreak. House said this curve is a standard tool used by epidemiologists to show the progression of an outbreak over time, including, but not limited to, the most likely time period of exposure and the magnitude at any particular point in time.
"An 'epi curve' uses the symptom onset date — or testing date for those who are asymptomatic — which is the preferred method of communicable disease analysis because it improves timeliness of trend interpretation," House said.
Weight is also given to trends in neighboring counties, including a three-day rolling average, a consecutive decline or increase over a 14-day period, and the incidence rate among the population.
Based on that methodology, House said the needle might not move again for some time.
“Since the incubation period of COVID-19 is 14 days, once a color is increased to a higher level of risk, we will not decrease that risk level for a minimum of 14 days until we have seen a steady decline in our numbers," House said. “The most recent change was prompted by a 14 day decrease in active cases, the three-day rolling average of new cases, as well as data analyzed by the [Centers for Disease Control and Prevention] that is suggested be used in making these types of decisions.”
