Diagnosis of COVID-19 by rt-PCR is considered to be the gold standard but the diagnostic sensitivity of this tool has been found to be imperfect. It is estimated that the search for SARS-CoV-2 RNA by rt-PCR results in a diagnosis in about 70% of cases, and serological tests may prove to be a highly relevant complementary tool. The imperfect diagnostic sensitivity of RT-PCR is not only related to the detection limit of the technique, but also to the nature and quality of the sample, and date of sampling vs. early symptoms.
Similarly, it may also be related to a clinical form of the disease with a very strong antiviral response and an explosive inflammatory reaction, allowing for a rapid elimination of the virus. So, in clinical practice, for several patients with a severe pathology, who were hospitalized in intensive care units, viral RNA was not detected in respiratory specimens, even though the clinical and radiological arguments unequivocally pointed to a COVID-19 infection.
This new study aims at understanding the pathophysiology of severe forms of COVID-19, especially when the pathogen in question is no longer detectable.
The objective of this work is to compare the antiviral response profile of “viral RNA negative” patients in severely affected patients in intensive care units to that of patients with a positive viral RNA search using the following assays:
- Interferon α and other cytokines
- Anti-SARS-CoV-2 antibodies to multiple antigenic targets
- Search for neutralizing antibodies to SARS-CoV-2
- Search for facilitating antibodies to SARS-CoV-2
Enagnon Kazali Alidjinou