When used in children, the rapid antigen tests do not meet the accuracy criteria established by the WHO.
Below is a summary of some recent studies of COVID-19. They include research that warrants further study to confirm the findings and has yet to be certified by peer review.
Rapid antigen testing can be unreliable in children
When used in children, rapid antigen tests for detecting the coronavirus do not meet the accuracy criteria set by the World Health Organization and US and UK device regulators, according to researchers who reviewed 17 studies of the tests.
The studies evaluated six brands of testing on more than 6,300 children and teens through May 2021. In all but one of the studies, the tests were administered by trained employees. Overall, compared with PCR tests, the antigen tests failed to detect the virus in 36% of infected children, the researchers reported in BMJ Evidence-Based Medicine on Tuesday. In children with symptoms, it missed 28% of infections. In infected children without symptoms, the tests missed the virus in 44%. Only about 1% of the time, the tests falsely detected the virus in a child who was not actually infected.
Given that more than 500 antigen tests are available in Europe alone, the authors said, “the performance of most antigen tests under real-world conditions remains unknown.” But the new findings “cast into doubt the effectiveness” of rapid antigen testing for widespread testing in schools, they concluded.
Transmission of COVID-19 through breast milk unlikely
A new study appears to confirm smaller, previous studies that suggested breastfeeding mothers are unlikely to transmit the coronavirus in breast milk.
Between March and September 2020, researchers collected multiple breast milk samples from 110 nursing women, including 65 with positive COVID-19 tests, 36 with symptoms that had not been tested, and a control group of 9 women with negative COVID-19 tests. Seven women (6%) — six with positive tests and one who had not been tested — had non-infectious genetic material (RNA) of the virus in their breast milk, but none of the samples showed any evidence of active virus, according to a report published on Wednesday in Pediatric Research. Why breast milk would contain coronavirus RNA but not an infectious virus is unclear, said study leader Dr. Paul Krogstad of the David Geffen School of Medicine at UCLA, “Breast milk is known to contain protective factors against infection, including antibodies that prevent both the mother’s exposure to viruses and other infectious agents and to vaccines she has received,” noted he up.
The U.S. Centers for Disease Control and Prevention (CDC) recommend that women with COVID-19 should wash their hands or use hand sanitizer with at least 60% alcohol before breastfeeding, bottle feeding, or expressing milk. The CDC also recommends that they wear a mask if they are within 6 feet of the baby.
New technique could speed up vaccine, antibody drug development
Researchers are working on a way to accelerate the development of vaccines and monoclonal antibody drugs for COVID-19 and other diseases, reducing the time between collecting blood samples from volunteers and identifying potentially useful antibodies from months to weeks.
As detailed in Science Advances on Wednesday, the new technique uses cryo-electron microscopy, or cryoEM, where the biological sample is frozen to view it with as little distortion as possible. Currently, “generating monoclonal antibodies involves several steps, is expensive, and usually takes somewhere on the order of two to three months, and at the end of that process you still need to perform structural analysis of the antibodies” to find out where they are. bond with their target and how they actually work, explains Andrew Ward of the Scripps Research Institute in La Jolla, California.
In experiments that used the new approach to look for antibodies to HIV, “we turned the process on its head … by starting with structure,” Ward said. Because cryoEM offers such high resolution, rather than laboriously sorting through antibody-producing immune cells one by one to identify promising antibodies, the process of identifying antibodies, mapping their structure and seeing how they kill viruses and other targets can attack much faster, he added. “The ongoing COVID-19 pandemic has highlighted the need for such robust and rapid technologies,” his team concluded.
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