COVID-19 cases have continued to rise in South County in the weeks since it was singled out as a virus hotspot in the St. Louis metropolitan region, even as cases began to decline in other areas.

The region’s “red zone” switched from St. Charles County to South County, especially Oakville’s 63129 ZIP code and Concord’s 63128, Dr. Alex Garza, head of the St. Louis Metropolitan Pandemic Task Force, said Aug. 10. SSM Health CEO Garza specifically singled out Oakville, Sappington, Fenton and Arnold as notable areas of high transmission trending in the wrong direction since the beginning of August, while other areas outside of South County started to decline.

The gold standard in establishing trends in the coronavirus, the seven-day rolling average of hospital admissions, had gone down for several days in St. Louis for the first time in more than a month, an achievement celebrated by Garza — although that overall number has since stayed the same.

But the “promising trends in our regional data” as of Aug. 10, including the task force’s modeling, “gives us a little bit of hope that we’re starting to turn the tide” in COVID-19 cases, Garza said. He attributed the lower numbers to the mask mandates in St. Louis County and St. Louis city, which went into effect in early July, and called it a “good sign that we’re starting to flatten that curve” on the pandemic.

“We’re not seeing a huge drop, but we are starting to see it turn,” Garza said, although he cautioned that “there’s so much virus circulating right now that it’s going to take a little bit of time before you really start seeing significant drops.”

But in data separated by ZIP code, South County stood out.

“You’ve seen us in weeks before where it was out in St. Charles County and Chesterfield, and now the numbers seem to be increasing down in South County,” Garza said. “I’ll point out a couple of areas here where we’ve seen some increase — Arnold, Sappington and Oakville is where we saw the increase in numbers.”

In the weeks since Garza singled it out as a hotspot, the rate of cases per 1,000 residents has gone up in every South County ZIP code. The day after Garza mentioned the rise in South County, the ZIP code-level data showed that Oakville had 604 total cases, for a rate of 11.25 cases per 1,000. In the days since, Oakville has gone up by 147 cases to 751 total cases, now standing at a rate of 13.99 cases per 1,000.

The Concord ZIP code of 63128 had 321 cumulative cases at the time of the briefing, for a rate of 10.76 cases per 1,000. In the weeks since, Concord has 136 more cases for a new rate per 1,000 of 15.32, the highest infection rate in South County.

Affton’s 63123 ZIP code, which was not singled out by Garza, has risen from the 595 cases reported Aug. 11 to 759 cases, edging Oakville for the largest total number of cases. The rate per 1,000 in Affton has risen to 14.84 from 11.64 as of two weeks ago.

The 63125 ZIP code in Lemay had 381 cases as of Aug. 11, for a rate per 1,000 of 11.63. That has gone up to 457 cases and a rate per 1,000 of 13.84.

The 63126 ZIP code of Crestwood and Sappington had 130 cases last week and now has 175 cases. The rate per 1,000 has gone up from 8.8 to 11.84.

Sunset Hills’ 63127 ZIP code has the fewest cases of any South County ZIP code with 38 total cases as of Aug. 11, for a rate per 1,000 of 7.62. But it’s risen to 58 since then, a rate per 1,000 of 11.83.