Universal Surveillance for COVID-19 Works for 1 Hospital

March 12, 2021
Frank Diamond

Investigators conclude that asymptomatic carriers increased the duration of the pandemic. Every patient should be tested for COVID-19.

Test all patients who go to a hospital for coronavirus disease 2019 (COVID-19) even the ones who don’t exhibit COVID-19 symptoms and are there for other medical reasons. It’s very possible that over a third of those patients who aren’t there for COVID-19 will be asymptomatic carriers of the disease who may endanger health care workers and other patients, according to a study in the American Journal of Infection Control.

“The proportion of asymptomatic patients admitted with SARS-CoV-2 was significant,” write investigators with the University of Louisville. “Identifying and isolating asymptomatic patients likely prevented exposure and development of hospital-acquired COVID-19 cases among health care workers and other patients, supporting the universal surveillance of all admitted patients.”

Investigators reached this conclusion even while acknowledging that such an approach can present logistical and financial hurdles that include an increase in the cost of testing and use of the laboratory. Universal surveillance was instituted at the University of Louisville Hospital last April. The data were collected on patients from April 9, 2020 to July 1, 2020. Those who tested positive for COVID-19 were divided into symptomatic or asymptomatic categories, using the 11 symptoms that the Centers for Disease Control and Prevention (CDC) says should be watched for.

After reviewing 2882 COVID-19 tests, they found that 103 tested positive for the disease with 65 (63%) being symptomatic and 38 (37%) being asymptomatic.

“The proportion of SARS-CoV-2 patients who were asymptomatic varied over the duration of the study but trended up from 20% at the onset of the study period to 60% at the end.”

Investigators conclude that asymptomatic carriers increased the duration of the pandemic.

“The reason that we currently isolate asymptomatic and symptomatic SARS-CoV-2 patients in the hospital is based on the indirect finding that they shed live virus,” the study states. “Thus, the premise of isolating asymptomatic positive patients is to contain the shedding of live virus.”

The most common reasons for admitting asymptomatic patients were trauma or labor. Investigators also found some socioeconomic factors involved.

“Known risk factors for COVID-19 include persons frequently in congregate settings with an increased likelihood of close contact,” the study states. “The risk factors were exemplified in our population as pregnancy, poverty and crowding. These clusters represented a group of pregnant Hispanic patients from one area, and additional clusters of both symptomatic and asymptomatic patients in densely populated urban parts of the city. This type of information could contribute to outbreak investigations by a health department.”