States Undercount Positive Rapid Tests, Masking the Spread of Disease
New York Times
Public health officials are warning that as rapid antigen tests become increasingly available, their use may lead to a significant undercount of COVID-19 cases, making it more difficult to identify the spread of the novel coronavirus. These tests include "point-of-care," DIY, and home antigen tests. Under Centers for Disease Control and Prevention guidance, states must report cases based on polymerase chain reaction (PCR) tests and antigen testing. However, seven states and Washington, DC, do not publicly share case counts for those with antigen positive tests, including California, New Jersey, and Texas. Another six states keep these counts separate from their overall case numbers, and most report these counts less frequently. The rapid tests are not as "confirmatory" as PCR tests because they can fail to detect low levels of the coronavirus. The majority of states, however, regard antigen positive cases or "probable" cases the same as "confirmed" cases, and conduct follow up with interviews and contact tracing. People who test positive from rapid tests represent a small but growing portion of all publicly reported cases. For instance, positive cases from antigen tests in Florida comprise roughly 4 percent of all cases reported since March, most of which are based on PCR testing. But on a daily basis, antigen tests contribute a more noticeable share, representing as much as one-third of reported cases in recent days.
HHS and DOD Announce $119 Million Contract to Hologic to Better Meet the Demand of COVID-19 Testing
HHS News Release
The Department of Health and Human Services (HHS) and Department of Defense (DOD) recently awarded Hologic, Inc. a $119 million contract to expand its domestic COVID-19 diagnostic testing capacity. Hologic will focus on strengthening the capacity for COVID-19 tests in its facilities in Wisconsin, Maine, and California to increase their production capacity to 13 million tests per month by January 2022. Hologic received ongoing support to develop COVID-19 testing for these systems from the Biomedical Advanced Research and Development Authority (BARDA), part of the HHS Office of the Assistant Secretary for Preparedness and Response. BARDA will provide funding support for development of the Hologic COVID-19 diagnostic tests, while the Food and Drug Administration granted emergency use authorization to Hologic's Panther Fusion2 and Aptima assays in March 2020 and May 2020, respectively. The tests run on the company's fully automated Panther Fusion and Panther systems. More than 2,000 of these systems have been installed in clinical diagnostic laboratories globally, including in all 50 U.S. states. This investment was led by the DOD's Defense Assisted Acquisition in conjunction with the Department of the Air Force's Acquisition COVID-19 Task Force and funded through the Health Care Enhancement Act.
A Rapid Virus Test Falters in People Without Symptoms, Study Finds
New York Times
The Trump administration has purchased and distributed millions of rapid COVID-19 tests, but a study by researchers at the University of Arizona raises questions about their performance. The study found that in symptomatic people, a rapid test made by Quidel could identify more than 80 percent of COVID-19 infections found by a slower, lab-based polymerase chain reaction (PCR) test. When the rapid test was used to randomly screen students and staff members who did not feel sick, it detected just 32 percent of the positive cases identified via PCR testing. David Harris, PhD, a stem cell researcher at the university, and his colleagues evaluated nearly 2,500 people from June to August. Among 885 people who had COVID-19-like symptoms or were recently exposed to the coronavirus, 305 tested positive by PCR, of whom 54 were missed by the antigen test, or 18 percent. Some PCR-based tests can be configured to generate the cycle threshold (CT) number, which increases as the amount of virus in the body decreases. Of 13 asymptomatic people who were not identified by the Sofia rapid test, 12 had CT values in the 30s. The researchers were also unable to grow the coronavirus out of samples from volunteers whose PCR tests had CT numbers above 27. When Harris and his colleagues removed all PCR positives with CT values above 30 from their data set, the rapid test detected more than 85 percent of the coronavirus infections detected by the lab test, regardless of whether people were symptomatic.