Serial COVID-19 testing detects asymptomatic, presymptomatic infections in Louisiana jail
Testing of quarantined inmates and detainees in a Louisiana facility identified “a high proportion” of asymptomatic and pre-symptomatic persons who likely would have been missed through symptom screening only, according to findings in MMWR.
Approximately one-fourth of individuals with positive test results had one or two negative tests at some point while quarantined. In addition, 45% reported no symptoms at the time of testing.
“Transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), by asymptomatic and presymptomatic persons poses important challenges to controlling spread of the disease, particularly in congregate settings such as correctional and detention facilities,” Henry Njuguna, MD, of the CDC’s COVID-19 Response Team, and colleagues wrote.
One such example of these challenges began on March 29, 2020, when a staff member at a correctional and detention facility in Louisiana developed symptoms of COVID-19 and later tested positive for COVID. From April 2 to May 7, two additional cases were identified among staff members at the facility and 36 cases were detected among inmates and detainees at the facility. These persons were moved to isolated quarters and their previous dormitories were quarantined.
On May 7, the CDC and the Louisiana Department of Health began an investigation to evaluate the rate of COVID-19 infections among inmates and detainees living in quarantined dormitories in order to examine symptoms in this setting and evaluate the effectiveness of serial testing to identify additional infected persons in an effort to mitigate transmission.
According to the study, from May 7 through May 21, testing of 98 inmates and detainees residing in the five quarantined dormitories identified an additional 71 cases of COVID-19 infection. Researchers found that 32 (45%) occurred in persons who reported no symptoms at the time of testing, including three who were presymptomatic.
A quarter of these cases (n = 18) were identified in persons who had negative test results during previous rounds of testing. According to the researchers, serial testing of contacts from shared living quarters detected persons with COVID-19 who would not have been identified by symptom screening alone or by testing at a single time point.
“Early detection and isolation of persons with COVID-19, along with testing of close contacts, can slow the transmission of SARS-CoV-2 in correctional and detention facilities,” the authors wrote. “Serial testing, particularly for close contacts of patients, is important for complete identification of cases and prompt public health response in congregate settings.”