become a crucial datapoint in tracking a community’s success or failure in
containing the COVID-19 pandemic.
a simple enough ratio: the percentage of people who test positive for
COVID-19, out of the total number of people tested. Simple as it is, though,
test-positivity has proved to be a key measure of a community’s response to
COVID-19, both in terms of the community’s testing infrastructure and its
efforts to check the contagion.
Thus, in the early
days of the pandemic, when testing supplies and facilities were limited to
the point of being rationed, the national test-positivity rate was
approximately 20 percent. That is, out of every five people tested for
COVID-19, one tested positive. It certainly wasn’t the case, in March and
April, that one out of every five people in the country was infected, but
that only those with the highest probability of having been infected--the
sickest, the most symptomatic--were even able to secure a doctor’s order for
a test. Those presenting minor flu-like symptoms were typically sent away,
in the hope that they only had the flu. Test-positivity, in other words, is
an excellent indicator of the penetration and availability of testing within
a community: the lower the rate, the more people a community is managing to
But also, over
time: the lower the rate, the fewer sick people there are seeking testing, a
strong indication that the overall number of new cases in a community is
As a benchmark, the
CDC’s guidance on re-opening, issued on May 14, recommended a test-positivity
rate in a given community of under 10 percent among symptomatic,
asymptomatic, and presymptomatic persons. The World Health Organization’s
guidance, issued on May 12, recommended an even lower rate: 5 percent or
less for at least 14 days.
benchmarks in perspective. On May 5--the day after the State of Indiana
officially began its phased-in re-opening--Porter County’s test-positivity
rate was 14.9 percent, well above both WHO’s benchmark and the CDC’s, but
well below Indiana’s rate (18 percent); Lake County’s (20.8 percent); and
LaPorte County’s (17.2 percent).
Five weeks later,
as of Tuesday, July 14, Porter County’s test-positivity rate has nearly
halved, falling to 7.8 percent, well within the CDC’s guidance. Indiana’s,
in the meantime, has fallen to 9.1 percent; Lake County’s to 12.2 percent;
and LaPorte County’s to 7.4 percent, nearly half a point lower actually than
However, a biweekly
calculation of Porter County’s test-positivity rate since May 5 points to a
disconcerting trend beginning in mid-June:
-- Between May
6-19, the test-positivity rate dropped to 11 percent from 14.9 percent.
-- Between May
22-June 2, the rate dropped to 8.1 percent.
-- Between June
3-16, the rate plunged to 3 percent.
-- Then, between
June 17-30, the rate inched a full point higher, to 4 percent.
-- And, in the last
two weeks, July 1-14, it’s more than doubled, to 9.2 percent.
That sharply upward
trend in Porter County’s test-positivity rate coincides with a surge in new
cases since mid-June, over the course of which in just four weeks a 10-week
low of 25 new cases (the week ending June 13) swelled to an all-time high of
99 new cases (the week ending July 11), with a total of 254 new cases over
There is one thing,
on the other hand, which the upward trend in the test-positivity rate does
not coincide with: an increasing number of tests conducted over those four
In fact, just the
-- In the seven-day
period June 17-23, the Health Department reported 1,369 tests, an average of
196 per day.
-- In the period
June 24-30: 1,382 tests, an average of 197 per day.
-- In the period
July 1-7: 1,055 tests, an average of 151 per day.
-- In the period
July 8-14: 1,043 tests, an average of 149 per day.
In other words,
over the same four-week period in which each week saw a higher number of new
cases than the previous one--35, 51, 69, and 99--the average number of tests
conducted per day in the first half of the period, June 17-30, plummeted by
24 percent in the second half, July 1-14: from 196.5 to 150.
Those 254 new cases
are not, accordingly, an artifact of increased testing but in fact evidence
of a resurgence of COVID-19 in Porter County, as the spike in the test-positivity
Chesterton Tribune has been making consistent note of, those 254 new
cases since June 13 have been accompanied neither by an increase in
hospitalizations nor by an uptick in deaths. Since June 16 no more than four
patients have been hospitalized on any given day in Porter County (compared
to a high of 28 hospitalizations on May 20); and only two deaths have been
recorded since June 22 (compared to a one-week high of six in the week
ending June 6).
The demographics of
these new cases suggest why: the overwhelming majority of the newly infected
are young people under 50, most of them under 40. These people are less
likely to be hospitalized with COVID-19, less likely to become gravely ill,
and far less likely to succumb to their sickness.
hospitalizations and deaths tend to lag behind new cases by two to four
weeks. If, by August, hospitalizations remain low here and no or few
additional deaths have been reported, it will mean that Porter County’s most
vulnerable population--older folks with pre-existing conditions and
co-morbidity factors--have managed to avoid being infected by their children