Columbia/Boone County Public Health and Human Services issues correction of COVID-19 positivity rate

(COLUMBIA, MO) - Columbia/Boone County Public Health and Human Services (PHHS) has corrected and updated the COVID-19 positivity rate for Boone County residents on the COVID-19 Information Hub. This information was updated after PHHS was notified of a reporting error from Missouri Department of Health and Senior Services (DHSS).

On Sept. 3, PHHS was notified by DHSS that a lab in Boone County was unable to transmit all negative results electronically to DHSS since May 1. Issues with the data transmission appear to have been caused by a complex data extraction issue between MU Health Care’s electronic medical record contractor and DHSS. There was no delay in positive results, as those are also reported directly from the lab to PHHS. All patients were notified of test results in a timely manner and the only reporting error was to DHSS. Upon being notified of this data issue, PHHS halted publishing a positivity rate, as the number of results received on each day contributes to the denominator for the positivity rate calculation.

Attached to this release is the revised positivity rates for all weeks between May 1 and Sept. 4. This graph, and corrected positivity rates, will be updated on the Information Hub with the end of day update at 4 p.m. on Sept. 15. The additional negative test result data has resulted in a lower positivity rate than previously recorded. However, the positivity rate has still increased over time.

"The updated positivity rate still indicates an increase in the transmission of the COVID-19 virus and that there should be an increased focus on testing availability within Boone County," said Director of PHHS Stephanie Browning.

The positivity rate is used to help assess how the pandemic is changing in the county and whether the spread of the virus is improving or not. A physician’s order continues to be required for COVID-19 testing, with the exception of a few community-based testing events. Under the current testing criteria in Boone County, a rising positivity rate indicates that more people with symptoms of the virus or those who have been exposed through close contact are becoming infected with the virus.

Policy decisions are not made solely based on the positivity rate in Boone County. The Public Health Order announced on Aug. 28 was determined by an increased number of positive cases, specifically in young adults between the ages of 18-24, as well as trends showing increased transmission among other age groups. These infections are happening in situations in which people are gathering together and ignoring social distancing and mask requirements. PHHS analyzes all data in order to determine policy decisions, rather than focusing on one metric.

"The positivity rate provides insight into how the COVID-19 virus has spread within our county over time, but it is not the sole tool when making decisions," said Browning. "Our PHHS team continues to look at all aspects of the COVID-19 pandemic and how it may affect the health and safety of all those who live in Boone County."

In addition to the positivity rate, PHHS also monitors other metrics including the number of hospitalizations and deaths, the mode of transmission, and the age breakdown of all cases. Notably, one of the most important metrics is the 14-day case rate, which shows how the number of new cases has grown over a two-week period. Increased cases contribute to the overall capacity of case investigation and contact tracing efforts.

Due to obtaining the backlog of negative test results, PHHS will change the way in which test results are recorded. As of Sept. 15, PHHS will record COVID-19 results on the day the specimen was collected instead of the day the results were received. Please note that this may mean that the number of tests and positivity rate may change after publication if more test results are received. 

All updates on the number of COVID-19 test results received and the positivity rate can be found on the Sept. 15, 2020 update of the Information Hub at como.gov/coronavirus.