The Colorado Department of Public Health and Environment on Thursday updated its COVID-19 case numbers to 3,728 cases, with 710 patients hospitalized and 97 deaths – but the count could actually be higher. 

The virus has spread across 51 counties in the state, with 21 outbreaks at residential and non-hospital health care facilities. Denver County has the most cases, with 643. El Paso and Weld counties have both experienced 16 deaths, the most in the state. 

The state reported that 11 people have died of the virus in Denver. However, Mayor Michael Hancock’s office reported 15 deaths as of Thursday. 

“I think the discrepancy is just that there’s a lag in reporting,” said Evan Dreyer, Hancock’s chief of staff. “Our numbers are pretty close to real time.”

The CDPHE also stated that 19,788 people had been tested for the virus.

The department notes that cases include people who had a positive lab test and cases that public health identified and determined were likely to have COVID-19 because of their symptoms and close contact with someone who tested positive. The number of untested cases included in the total case count is a very small portion of the total cases reported.