A group of Brazilian scientists is studying a case of infection with the new coronavirus that lasted at least 218 days, with the virus replicating and mutating during this period. The team describes this phenomenon as “worrying” as it indicates the emergence of variants more adapted to the human body.
The study was conducted by scientists from the University of São Paulo (USP) with support from the São Paulo State Research Support Foundation (FAPESP) And published this week on the MedRxiv platform to make this case public. The analysis has not yet been peer reviewed (expert review).
The patient, a 40-year-old man, tested positive for the disease between September 2020 and April this year. Before being diagnosed with covid-19, the patient underwent aggressive cancer treatment, resulting in a severely weakened immune system.
“Throughout this period, there was a risk of transmitting the infection to others,” explained Maria Mendes-Correa, a professor at the USP School of Medicine and the first author of the study. The situation was confirmed in exams. in vitro from the nasopharynx and weekly saliva samples, in which an increase in viral load could be observed after a few hours.
“This ability to replicate the virus was observed continuously and persistently for 196 days in a row” out of 218 days of infection, said Maria Mendes-Correa.
Blood, urine, and anal samples were also collected between January and April of this year, also indicating that SARS-CoV-2 persisted for most of the study period. On the other hand, serological tests showed that the patient never developed antibodies.
The scientists also discovered mutations in pathogens throughout the infectious process by genetic sequencing of nasopharyngeal samples collected at 77, 134, 169 and 196 days after the onset of the first symptoms. Some of these mutations happened in squirrel spikewhich the virus uses to enter human cells.
Maria Mendez-Correa explains that the evidence suggests that the evolution of the virus “took place within a single host”, when, as a rule, these changes are “observed in the community.”
“This is a disturbing phenomenon as it promotes the emergence of viral variants that are more adapted to the human body,” the researcher added.
The patient in question spent most of his time in the hospital and remained isolated for short periods when he stayed at home.
