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This illustration, created at the Centers for Disease Control and Prevention, reveals the structure of the novel coronavirus. The illness caused by this virus has been named COVID-19.

Next Friday, Lancaster and nine other eastern Pennsylvania counties will become the state’s last jurisdictions officially moved from “red” to “yellow” by Gov. Tom Wolf.

As the date for a partial reopening of the economy approaches, some of the trends are good and some are more troubling.

Perhaps the most troubling for Lancaster County — where local Republican leaders declared their own move to “yellow” on May 15 — is that the number of new coronavirus cases has been higher in the second half of May than it was in the first half.

Every other county set to reopen on June 5 — including hard-hit Philadelphia, Delaware and Montgomery — had fewer cases in the second half of the month than in the first half, according to data from the state Department of Health.

Also turning yellow on June 5 are Berks, Bucks, Chester, Lackawanna, Lehigh and Northampton.

For each of the final Pennsylvania counties moving to yellow, LNP/LancasterOnline compared case and testing data from the past 14 days (May 15 through 28) with data from the first 14 days of May (May 1 through 14). Here’s what we found:

Case numbers going down, except for Lancaster

Lancaster County had 599 new cases in the first half of the month, and 692 in the second half. That’s a 16% increase and it stands in contrast with decreases that ranged from 4% (Montgomery) to 48% (Bucks) in the other nine counties preparing to reopen in a week.

Pace of testing is picking up

The higher case numbers in Lancaster County can partly be attributed to more testing, although other counties increased testing and still saw declines in new cases.

Testing increased in all 10 counties and is one of the key reasons Wolf has given for moving the hardest-hit counties to yellow. More testing means more information that can be used to combat the spread of COVID-19.

The number of people who were tested for coronavirus in Lancaster County was 41% higher in the second half of the month, compared to the first half, and that ranked Lancaster third among the 10 counties. But two of those other counties increased testing faster than Lancaster, and still saw decreases in the numbers of new cases.

Montgomery County had a 53% jump in testing and still saw a 4% decline in new cases. Chester County had a 46% increase in testing and saw a 14% drop in cases.

Rate of positive tests is dropping

As the number of people tested has increased, the portion of them testing positive for COVID-19 has gone down. For the 10 counties as a group, the rate of positive tests fell from 21% in the first half of the month to 12% in the second.

But Lancaster had the smallest decrease, from 16% in the first half of May to 13% in the second half. In the first half of the month, Lancaster’s positive rate was the lowest of the 10 counties. In the second half, it was second to highest, trailing only Delaware at 14.2%.

Portion of population tested is still small

The vast majority of Pennsylvanians have not been tested for coronavirus, and for the 10 counties turning yellow on June 5, the figure is 4.2%, or one in every 24 people.

Despite its increases in testing, Lancaster ranks second to last among the final yellow counties in portion of its population tested. Some 3.4% of Lancaster County residents have been tested so far. Only Chester County, at 2.7%, had a lower cumulative testing rate as of Thursday.

All 10 counties are still far above Wolf’s old metric

For weeks, Wolf maintained that no county should move to yellow if it had more than 50 total new cases per 100,000 population over a 14-day period. He compromised on that last week, when he announced that because of ramped up testing and contact-tracing, he will allow the final counties to partially reopen on June 5.

And as of Thursday, the 10 final counties moving to yellow remained two to four times above Wolf’s prior threshold. Scores ranged from a low of 92 in Lehigh to a high of 191 in Delaware. Lancaster’s score was 127, up from a low of 102 on May 20.

Here's how many new cases each county had in each half of the month, how much that changed, and how much testing increased in each county.


New cases

New cases

Change in



May 1-14

May 15-28


in tests