The Children’s Health Defense Fund has published this excellent resource for understanding a range of discrepancies and unanswered questions, including these two critical issues:
CDC reduces Ct threshold for COVID testing but only for the vaccinated
As of April 26, 2021 more than 9,245 COVID cases had been reported in the fully vaccinated, known as “breakthrough cases.” The CDC recently recommended reducing the RT-PCR Ct value to 28 cycles when testing fully vaccinated people for COVID.
The lower threshold would result in a decrease in positive breakthrough cases, calling into question COVID vaccine efficacy data.
According to the Indian Council of Medical Research (ICMR), a patient is considered positive for COVID if the Ct value is below 35. In other words, if the virus is detectable after 35 cycles or earlier, then the patient is considered positive.
“If the benchmark were to be lowered to 24 it would mean that Ct values in the range 25-34 would not be considered positive. A benchmark of 35, therefore, means that more patients would be considered positive than we would get if the benchmark were 24.”
We asked the CDC to explain why it changed the recommendations for COVID testing in vaccinated patients, the impact this will have on reports of breakthrough COVID cases and why the agency does not apply one RT-PCR testing standard for testing, regardless of vaccination status.
CDC stops counting all breakthrough cases (COVID infected among the vaccinated)
Federal health officials this month decided to limit how they monitor vaccinated people infected with COVID, drawing concern from some scientists who said the missing data could hinder scientists’ ability to investigate why and how breakthrough cases happen, Bloomberg reported.
Every Friday, the CDC posts the number of breakthrough cases in fully vaccinated individuals on its website. On May 7, the CDC announced it will transition to reporting only patients with COVID breakthrough infection who were hospitalized or died to “help maximize the quality of the data collected on cases of greatest clinical and public health importance.”
The change in reporting, which takes effect May 14, will reduce the number of breakthrough cases reported.
We asked the CDC to explain why the agency altered the way it counts COVID breakthrough cases, to explain the effect this will have on breakthrough numbers and how the CDC can monitor vaccine efficacy if it excludes breakthrough cases of COVID that do not result in hospitalization or death.