Implementation of a Rural Community Diagnostic Testing Strategy for SARS-CoV-2 in Upstate South Carolina

Abstract

By developing a partnership amongst a public university lab, local city government officials and community healthcare providers, we established a drive-through COVID-19 testing site aiming to improve access to SARS-CoV-2 testing in rural Upstate South Carolina. We collected information on symptoms and known exposures of individuals seeking testing to determine the number of pre- or asymptomatic individuals. We completed 71,102 SARS-CoV-2 tests in the community between December 2020-December 2021 and reported 91.49% of results within 24 h. We successfully identified 5,244 positive tests; 73.36% of these tests originated from individuals who did not report symptoms. Finally, we identified high transmission levels during two major surges and compared test positivity rates of the local and regional communities. Importantly, the local community had significantly lower test positivity rates than the regional community throughout 2021 (p < 0.001). While both communities reached peak case load and test positivity near the same time, the local community returned to moderate transmission as indicated by positivity 4 weeks before the regional community. Our university lab facilitated easy testing with fast turnaround times, which encouraged voluntary testing and helped identify a large number of non-symptomatic cases. Finding the balance of simplicity, accessibility, and community trust was vital to the success of our widespread community testing program for SARS-CoV-2.

Keywords: COVID-19; SARS-CoV-2; community health; rural; saliva testing; surveillance.

Figure 1

REDDI Laboratory community testing operation. (A) Overhead diagram of the community testing site layout. (B) Box of 50 ml saliva collection tubes labeled with unique QR codes. (C) Collection staff initiating a test for a community member. (D) Community member placing self-collected sample into a collection tray. Filled sample trays were placed in the orange biohazard box for transportation to the laboratory.

Figure 2

Number of SARS-CoV-2 molecular tests performed at Upstate South Carolina testing sites offered by SCDHEC, REDDI Lab, and other labs from December 1, 2020–November 30, 2021. The REDDI Lab group includes all community and non-community molecular tests performed by the REDDI Lab.

Figure 3

(A) Geographical distribution of SARS-CoV-2 molecular tests performed at the REDDI Lab from December 1, 2020–November 30, 2021 across Upstate SC. Nearly half of all REDDI community tests performed in Upstate SC were performed for residents of local towns of Central, Clemson, and Pendleton. The star indicates the REDDI Lab. Data is presented in tests per square mile. Tests in local towns were subtracted from the county totals and local town areas were subtracted from county areas; counties with 500 tests or less were omitted. The municipalities of Clemson and Clemson University were combined for community tests totals. (B) Number of SARS-CoV-2 saliva tests administered and positive results sorted by patient ZIP code. Local area is defined as the three nearest municipalities: Clemson, Central, and Pendleton (ZIP codes 29631, 29632, 29633, 29634, 29630, and 29670). The regional area includes all other municipalities in Upstate South Carolina, including those omitted from 3A. Note that the positive test number and test administered axes are scaled such that the positive test axis is 10% of the test administered axis.

Figure 4

Weekly turnaround time for community tests performed at REDDI Lab from December 1, 2020-November 30, 2021. Turnaround time was calculated by taking the difference between time of sample collection and time of result. This data was obtained from the clinical reporting platform (Rymedi, version 1.0, Greenville SC, USA).

Figure 5

Positivity rates of SARS-CoV-2 tests from different REDDI Lab community testing groups from December 1, 2020–November 30, 2021. Individuals self-reported exposures or symptoms during test initiation, so this can only serve as an approximate measurement. These data were obtained from the clinical reporting platform (Rymedi, version 1.0, Greenville SC, USA).