Low performance of antigen tests makes it difficult to evaluate the real scale of Omicron spread in schools
Rapid Covid-19 tests have demonstrated low effectiveness in detecting the virus in children, a team of British and German researchers has said, casting doubt on school testing programs.
Scientists from the University of Manchester and Germany’s Institute for Quality and Efficiency in Health Care analyzed 17 studies published between January 2020 and May 2021, involving 6,355 children who used eight antigen tests from six different brands.
According to the report, published by the BMJ medical journal, the lateral flow antigen tests used to detect coronavirus in children do not meet the minimum standards set by the World Health Organization and UK and US regulators.
The scientists concluded that “overall diagnostic sensitivity and specificity in pediatric populations was 64.2%” (and 71.8% among children with symptoms) with no test having fully satisfied its minimum performance requirements.
The difference in test performance between symptomatic and asymptomatic child patients shows “that sensitivity and specificity are not inherent test characteristics,” the researchers said. They also noted that in almost all the studies testing was conducted by trained staff, and that sample collection by untrained people or self-testing would likely make the tests’ performance even worse.
The low effectiveness of the lateral flow tests inevitably evokes questions about the rationality of mass testing programs in schools. “The observed low diagnostic sensitivity may impact the planned purpose of the broad implementation of testing programmes,” the report reads.
The return to school after the winter holiday break has been marked by a mass spread of Omicron cases among children, especially in the countries where younger kids are not eligible for vaccination, such as the UK. Meanwhile, according to a recent study by the US Centers for Disease Control and Prevention, children aged 5–11 are “at least as likely” to be infected with Covid as adults, though in most cases they have much milder symptoms.
