Point-of-care COVID antibody test is accurate, adaptable, low maintenance
Duke University researchers developed a point-of-care test (POCT) that can detect SARS-CoV-2 antibodies and four other coronaviruses with 100% accuracy, according to initial test results from a small cohort published in Science Advances late last week. The test is called DA-D4 POCT, with DA standing for double-antigen and D4 being the assay platform recently developed to detect Ebola infections 1 day faster than typical polymerase chain reaction tests.
The test uses a polymer brush coating that stops everything but the targeted molecules from attaching to the wet test slide, which can be zoned to delineate different biomarkers. In the case of SARS-CoV-2, it measures antibody responses against the spike protein, the binding domain within the spike protein, and the nucleocapsid protein. Fluorescence intensity of each zone is used to indicate antibody concentration.
Researchers measured the test's accuracy and sensitivity via samples from 31 patients admitted to intensive care for COVID-19, 41 healthy people pre-pandemic, and 18 individuals with seasonal coronaviruses. The test was able to correctly indicate SARS-CoV-2 cases with no false-positives, and further analysis on longitudinal samples from six COVID patients showed seroconversion and antibody kinetics.
"The DA-D4 POCT is a promising platform to supplement existing diagnostic technologies to manage the COVID-19 pandemic because it marries the best attributes of LFAs [lateral flow assays] and ELISAs [enzyme-linked immunosorbent assays]—it is quantitative, easy to use, widely deployable, requires only a single 60-µl drop of blood, and can be performed with minimal user intervention," write the researchers.
"The detector is battery powered and the test doesn't require any power at all, so you can throw the whole thing into a backpack and truly test at the point-of-care with minimal resources," added coauthor Jason Liu in a Duke University press release. He is a PhD student who designed and built the detector.
While this platform may not be used widely for COVID-19 detection, the researchers say its adaptable platform should also be able to be reconfigured to detect immune responses and predict disease outcome.
Jun 25 Sci Adv study
Jun 25 Duke University press release
Childcare closures in pandemic may have affected women more than men
Childcare facility closures due to COVID-19 may have affected US women more than men, according to a research letter late last week in JAMA Network Open.
The researchers looked at 48,920 individuals, 27.2% from states with mandated childcare closures, from January to December 2020 (all closures were rescinded by June 2020). Half were women, and the mean age was 43.3 years. Overall, 165,158 individual-months were tracked.
Data showed employment decreased for both sexes in April 2020, but the likelihood of women being employed was -2.6 percentage points in states during their mandated childcare closures (95% confidence interval [CI], -4.3 to -1.0 percentage points). This association only remained when controlling for households for children younger than 6 (-3.3 percentage points; 95% CI, -6.2 to -0.5 percentage points) and did not hold when the researchers analyzed households with children 11 and older and households with no children.
While Black and Hispanic people saw the largest differences in employment, the researchers note that Hispanic and White people saw the greatest sex-associated differences. Estimates from the interrupted time series model also indicate that men and women both experienced greater hours reduced in states with mandated childcare closures compared with those without (-3.9 and -5.8, respectively, vs -3.5 and -4.3). The researchers add that women in states that had childcare closures had a differential reduction of approximately 1 hour worked, regardless of employment.
Jun 25 JAMA Health Forum study