FDA addresses accuracy concerns with rapid COVID-19 test
The US Food and Drug Administration (FDA) says it’s working with Abbott Laboratories to address potential false-negative results provided by the company’s rapid coronavirus test.
In a news release yesterday, the FDA said it’s evaluating the information about inaccurate results reported for the Abbott ID NOW COVID-19 assay, which can provide results within 5 to 13 minutes. A preprint study published earlier this week found that the test missed between 33% and 48% of positive coronavirus samples at a New York City hospital. The FDA has also received 15 reports of adverse event related to false-negative test results.
“We will continue to study the data available and are working with the company to create additional mechanisms for studying the test. This test can still be used and can correctly identify many positive cases in minutes. Negative results may need to be confirmed with a high-sensitivity authorized molecular test,” said Tim Stenzel, MD, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health.
Abbott, in a company press release, said the results of the study conducted at New York University Langone Tisch Hospital are not consistent with other studies, and could reflect the test being used in ways it was not designed to be used. While the study evaluated some test results using nasopharyngeal samples transported in viral transport media, the company says the test is meant to be used with dry nasal swabs obtained at the point of care.
The FDA issued an Emergency Use Authorization for the Abbott ID NOW test on Mar 27, and since then it has been shipped to all 50 states. The system is also used by the White House to test staff members.
The FDA said it will continue to monitor interim data. Abbott has agreed to conduct post-market studies that will include at least 150 patients in a variety of clinical settings.
May 14 FDA press release
May 14 Abbott Laboratories press release
Stay-at-home order in Iowa may have slowed COVID-19 spread
A study today in JAMA Network Open looks at COVID-19 cases in border counties in Iowa, which never issued a stay-at-home order, and Illinois, which did so on Mar 21. The authors say the evidence indicates that a stay-at-home order in Iowa would have eliminated as many as 217 excess cases in the state within a month.
The cross-sectional study compared daily changes in COVID-19 cases per 10,000 residents in 8 Iowa counties bordering Illinois, to those in the 7 Illinois counties bordering Iowa before and after Illinois issued a stay-at-home order. The total population (based on 2019 census estimates) in the Iowa border counties was 462,445, compared with 272,385 in the Illinois border counties.
The authors noted that, from Mar 15 to Mar 21, when the stay-at-home order became effective in Illinoi), the average daily cases per 10,000 residents was 0.024 in the Iowa counties and 0.026 in the Illinois counties.
Within 10, 20, and 30 days after the enactment of the stay-at home order in Illinois, however, the difference in cases was −0.51 per 10 000 residents on day 10, −1.15 per 10,000 residents on day 20, and −4.71 per 10,000 residents on day 30, reflecting the decrease per population in Illinois compared with Iowa.
“The estimates indicate excess cases in the border Iowa counties by as many as 217 after 1 month without a stay-at-home order,” the authors wrote. “This estimate of excess cases represents 30.4% of the 716 total cases in those Iowa counties by that date.”
Iowa was one of only five US states to never issues a stay-at-home order, though school, restaurants, and several non-essential businesses were ordered to close in March and April. Iowa’s governor countered that these closures were comparable to stay-at-home orders in neighboring states.
May 15 JAMA Netw Open study
Distancing measures have big impact on COVID-19 spread, study finds
States and cities that imposed distancing measures, such as stay-at-home orders, had a big impact on the growth rate and spread of COVID-19, according to a modeling study from a team led by University of Kentucky scientists. The group published its findings yesterday in Health Affairs.
Using an event-study design, the investigators examined the impact of the measures among US counties from Mar 1 to Apr 27. For growth rate, the impact of the measures increased over time, reducing the daily growth rate by 5.4 percentage points after 1 to 5 days to 9.1 percentage points after 16 to 20 days.
The group predicted that COVID-19 spread would have been 10 times greater—meaning 10 million more cases—by Apr 27 without shelter-in-place orders. Without other measures such as event bans, school closures, and closures of other venues such as restaurants and gyms, COVID-19 spread would have been 35 times greater, potentially resulting in 35 million more cases.
The authors concluded that their findings outline the threat of exponential spread if interventions aren’t in place and provide information for reopening planning.
May 14 Health Aff abstract