Case data

Cases of COVID-19 by date reported to the state 

• What this graph shows: The number of COVID-19 cases being reported to public health each day because someone had a positive lab test or had symptoms of COVID-19 and were linked to someone with a positive lab test. 
• What to know about this data: 
  • This graph does not track the number of newly-diagnosed cases from day to day.
  • The reported date of a case can be re-assigned to an earlier date on rare occasions. 
  • The day someone got sick, the day they were tested, and the day public health was notified of the positive results might be several days apart.

Cases of COVID-19 by date of illness onset

• What this graph shows: The estimated date of when symptoms began for cases of COVID-19 reported to public health.
• What to know about this data: 
  • This graph does not track the number of newly-diagnosed cases each day.
  • This graph is referred to as the “epi curve” and shows the frequency of new cases based on the date of onset of disease. Over time, this graph will provide the best picture of the actual progression of illness during an outbreak. 
  • This graph will change every day as new cases are investigated and information is entered about when symptoms started for each person. Cases that test positive today could show up with a symptom onset date of several days or weeks prior. 
  • Date of symptom onset is usually obtained after public health is able to investigate a case. Because it takes time to investigate cases, this graph is often several weeks behind in providing an accurate picture of transmission.

Cumulative number of cases of COVID-19 in Colorado by reported date to the state

• What this graph shows: A cumulative total of the new number of COVID-19 cases that correspond to the date the case was reported to public health. 
• What to know about this data:
  • This graph shows that we continue to have cases reported every day.
  • This graph does not track the number of cases reported from one day to the next
  • As long as cases continue to be reported, this graph will always go up.
  • The reported date of a case can be re-assigned to an earlier date on rare occasions. 

Cumulative number of cases of COVID-19 in Colorado by date of illness onset

• What this graph shows: A cumulative total of the cases by the estimated date of when symptoms began. 
• What to know about this data:: 
  • This graph does not track the number of newly-diagnosed cases each day.
  • This graph will change every day as new cases are investigated and information is entered about when symptoms started for each person. 
  • Date of symptom onset is usually obtained after an epidemiologist is able to investigate a case. Due to the time it takes to investigate cases, this graph is often several weeks behind in providing accurate cumulative totals by onset date of illness.

Cases of COVID-19 in Colorado by county

• What this graph shows: The number of people testing positive for, or determined as a probable case of, COVID-19 in each county.
• What to know about this data:
  • People who test positive in Colorado while visiting are included in the county where they were identified.
  • Sometimes there is missing information or errors in preliminary data regarding county of residence. As more information is learned through case investigations, these numbers may change.

Case Rates per 100,000 People in Colorado by county

• What this graph shows: The rate of people testing positive for, or determined as a probable case of, COVID-19 in each county. 
  • NOTE ABOUT RATES: Because population sizes vary widely, rates are often used instead of counts to better compare the level of disease across different populations. This is done by dividing the number of cases in a community by the population of that community, and then multiplying that number by 100,000. Regardless of the true population of any given county, an estimated comparison can be made across populations by using a baseline of 100,000 people. 
• What to know about this data:: 
  • Caution should be used when interpreting rates in counties with small populations. In smaller populations with fewer cases, there is not enough information to make a valid comparison. Rates are not shown for counties with less than 5 cases. 
  • People who test positive in Colorado while visiting are included in the county where they were identified.
  • Sometimes there is missing information or errors in preliminary data regarding county of residence. As more information is learned through case investigations, these numbers may change.

Number of deaths from COVID-19 in Colorado by date of death

• What this graph shows: The number of deaths recorded by the date a death occurred. 
• What to know about this data:
  • Due to standard delays in the process of recording deaths in Colorado, it may be several days between the day a death occurs and the day the death appears in this graph. This means the number of deaths reported may change on a day-to-day basis (particularly within the past week) as reports of new deaths are received.

Cumulative number of deaths of COVID-19 in Colorado by reported date to the state

• What this graph shows: The cumulative number of deaths reported, corresponding to the date a person was reported to have COVID-19. The date a death is reported is often not the same as the actual date of death or the same as the date the case was initially reported to public health.
• What to know about this data:
  • This graph does not track the date a death was reported 
  • This graph does not track the number of deaths reported from one day to the next
    • Although we are tracking and collecting the date of death for each case, it can take several days before we receive a death certificate and are able to match the death to a known case. CDPHE is working with other state partners to streamline the process of reporting date of death in a more timely manner.
  • This graph will change every day as new deaths occur and those deaths are attributed to when cases were first reported for each person..
  • The furthest column to the right provides an accurate accounting of the total deaths of COVID-19 to date. 

Cumulative number of deaths from COVID-19 in Colorado by date of illness onset

• What this graph shows: The cumulative number of deaths, corresponding to the date a person began experiencing symptoms.
• What to know about this data: 
  • This graph does not track the date a death was reported 
  • This graph does not track deaths from one day to the next
    • Although we are tracking and collecting the date of death for each case, it can take several days before we receive a death certificate and are able to match the death to a known case. CDPHE is working with other state partners to streamline the process of reporting date of death in a more timely manner.
  • The furthest column to the right provides an accurate accounting of the total deaths of COVID-19 to date.

Cumulative number of hospitalized cases of COVID-19 in Colorado by date reported to the state

• What this graph shows: A cumulative running total of the number of people hospitalized with COVID-19, corresponding to the date their illness was reported. 
• What to know about this data:
  • Knowing how many people have been hospitalized helps us understand the severity of disease.
  • As long as cases continue to be hospitalized, this graph will always go up.
  • This graph does not track the cumulative number of people who are newly-hospitalized each day.
  • This graph does not track the number of people who have been discharged from the hospital.
    • Admission and discharge dates are not readily available for each patient. CDPHE is currently working with other partners to streamline this data and make it available.

Cumulative number of hospitalized cases of COVID-19 in Colorado by date of illness onset

• What this graph shows: A cumulative running total of the number of people hospitalized with COVID-19, corresponding to the date they began experiencing symptoms. 
• What to know about this data:
  • This graph does not track the number of newly-hospitalized cases each day.
  • This graph does not track the number of people who have been discharged from the hospital.
    • Admission and discharge dates are not readily available for each patient. CDPHE is currently working with other partners to streamline this data and make it available. 
  • This graph will change every day as new cases are investigated and information is entered about when symptoms started for each hospitalized person. Cases that are hospitalized today could show up with a symptom onset date of several days or weeks prior. 
  • Date of symptom onset is usually obtained after an epidemiologist is able to investigate a case. Due to the time it takes to investigate cases, this graph is often several weeks behind in providing an accurate picture of hospitalizations.

Positivity data from clinical laboratories

• What this graph shows: The total number of tests reported to CDPHE as being performed each day - and the percent of those tests that are positive for COVID-19. 
  • The number of tests from CDPHE’s state laboratory are indicated in tan, the number of tests from other commercial labs are indicated in blue. Test numbers correspond to the scale on the left side of the graph.
  • The red line indicates the percent of tests reported that are positive. The percent of positive tests correspond to the scale on the right side of the graph.
• What to know about this data:
  • The percent of positive tests is helpful for public health to track whether symptoms of people being tested are caused by COVID-19 (a higher positivity rate) or if their symptoms are being caused by something else (a lower positivity rate).
  • Total number of people tested might be underestimated because while most laboratories report all COVID test results to CDPHE, they are only required to report positive results.