SAN ANTONIO – As state officials updated the Texas Department of Health and Human Services COVID-19 dashboard on Wednesday, they included a note about Bexar County’s case count.
“The San Antonio Metro Health District has clarified its reporting to separate confirmed and probable cases, so the Bexar County and statewide totals have been updated to remove 3,484 probable cases. The local case count previously included probable cases identified by antigen testing but not those from antibody testing or other sources.”
The state’s count, which only includes confirmed cases, now shows more than 17,000 COVID-19 cases for Bexar County, while Bexar County’s local count shows more than 21,000 cases, combining confirmed and probable cases.
While DSHS has now omitted probable cases from the dashboard, the state health department established the guidelines for determining a probable case which includes individuals who have not had a positive PCR test for COVID-19, but who meet two of the following three criteria:
- A positive quick-result antigen test
- Experiencing COVID-19 symptoms
- Close contact with a confirmed positive COVID-19 case
In San Antonio, probable case counts specifically include symptomatic individuals who had a positive antigen test.
“Probable cases do not mean ‘maybe’ cases of COVID-19,” said Dr. Colleen Bridger, interim director of Metro Health. “Antigen tests are FDA approved, and positive tests are highly accurate. San Antonio is one of only three Texas cities collecting and reporting this data per the CDC guidelines, but the State of Texas wants apples-to-apples comparisons between Texas cities.”
San Antonio Mayor Ron Nirenberg on Friday announced that Metro Health will further break out probable and confirmed cases on its website, but explained why they will continue to count probable cases locally.
“From a science perspective and medical perspective, it doesn’t make any sense to not count these test results, as they are just as accurate in determining positive cases,” Nirenberg said. “This gives us a better sense of where the infections are so we can control it.”
Critics have said including probable cases could artificially inflate COVID-19 case numbers, but health experts have said probable cases are an accurate way to determine the spread of the virus.
“(An antigen test) is still considered an accurate positive. Experts actually prefer an antigen test be used when you’re testing large populations. Now in San Antonio as we have more widespread prevalence of COVID-19, it’s definitely a good test to use in our community,” Metro Health Assistant Director Mario Martinez said on Friday.
“To be clear, this is not an ‘error’ in Metro Health’s reporting,” Bridger said Thursday. “This is a disagreement over what should be reported in total counts. We will continue to align our definitions with those from the CDC and the Texas Department of State Health Services, while honoring the state’s request to separate probable cases.”
During flu season, the Centers for Disease Control and Prevention also counts probable cases to assess the spread of influenza.
The following is an explanation from UTHealth officials about the difference between antigen and PCR tests:
There are two types of tests, a polymerase chain reaction diagnostic (PCR) test, which uses a 6-inch-long swab inserted into the nasal cavity, and antigen tests, which are conducted through nasal swabs or mouth swabs. Antigen tests yield results in minutes but may give a false negative result. PCR tests results take longer but are more sensitive to the coronavirus and more accurate.
Antigen tests are not to be confused with antibody tests which look for the presence of antibodies in blood to determine whether a person has had an infection in the past.
Bexar County officials say they do not keep track of antibody test numbers and are not required to report them to the state at this time.