MOSCOW (MIPT) — As countries like Great Britain consider introducing testing regimes for international arrivals to ease travel restrictions, even as the media continue to cite coronavirus infection statistics by the hour, more people start wondering about the limitations of COVID-19 test kits and what actually constitutes being “infectious.” A biophysicist from MIPT involved in numerous virus studies is available for comments.
“A week or two after infection, as the immune system starts bringing the disease under control and the virus is subsiding, the probability that a test will detect its presence strongly diminishes,” explains MIPT’s Oleg Batishchev, associate professor of biophysics and the physics of living systems. “The method simply does not have the sensitivity that it takes to register individual viral particles. Sure, the patient might still transmit virus particles, but not nearly as often or as many. It is theoretically possible for that person to infect others, but the test will not indicate that. It is the case with many viruses that a test will perform well if used three days after symptoms present themselves, and the statistics cited [in the recent study in Annals of Internal Medicine] serve to confirm that rule.”
Oleg Batishchev is a researcher at MIPT. He has been involved in a number of virus studies and is available for questions about coronavirus tests and more.