A case of infection by the new coronavirus that lasted at least 218 days was described by researchers at the Universidade de São Paulo (USP) and collaborators in an article published on the medRxiv platform, still not peer reviewed.

It relates to a male patient, approximately 40 years old, who before contracting Covid-19, had undergone aggressive treatment against cancer and had a very weak immune system. He got infected in the beginning of September 2020 and only in April of this year had negative exam results.

"All nasopharyngeal secretion samples collected between the 6th and the 218th day after the onset of symptoms had a positive result for SARS-CoV-2 in the RT-PCR exam. And the virus was not simply present in the patient's body, it was also replicating. That is, throughout this period there was a risk of transmission to other people", says Maria Cássia Mendes-Correa, Professor at the Faculdade de Medicina da USP (FMUSP) and first author of the article.

Confirmation that the virus remained infective in the patient's body was carried out through in vitro tests, as part of a project supported by the State of São Paulo Research Foundation (FAPESP). In a laboratory with a high level of biosafety, headquartered at Institute of Tropical Medicine (IMT-USP), nasopharyngeal secretion and saliva samples collected weekly were incubated with cell lines susceptible to SARS-CoV-2. In the following hours, it was possible to observe an increase in viral load in cultures, as well as death of cells as a result of the action of the pathogen. "This replicative capacity of the virus was observed continuously and persistently over a period of 196 consecutive days”, reports the researcher.