Longitudinal Assessment of Nasopharyngeal Biomarkers Post-COVID-19: Unveiling Persistent Markers and Severity Correlations

SARS-CoV-19 infection
provokes a variety of symptoms;
most patients
present mild/moderate symptoms, whereas a small proportion of patients
progress to severe illness with multiorgan failure accompanied by
metabolic disturbances requiring ICU-level care. Given the importance
of the disease, researchers focused on identifying severity-associated
biomarkers in infected patients as well as markers associated with
patients suffering long-COVID. However, little is known about the
presence of biomarkers that remain a few years after SARS-CoV-2 infection
once the patients fully recover of the symptoms. In this study, we
evaluated the presence of persistent biomarkers in the nasopharyngeal
tract two years after SARS-Cov-2 infection in fully asymptomatic patients,
taking into account the severity of their infection (mild/moderate
and severe infections). In addition to the direct identification of
several components of the Coronavirus Infection Pathway in those individuals
that suffered severe infections, we describe herein 371 proteins and
their associated canonical pathways that define the different adverse
effects of SARS-CoV-2 infections. The persistence of these biomarkers
for up to two years after infection, along with their ability to distinguish
the severity of the infection endured, highlights the surprising presence
of persistent nasopharyngeal exudate changes in fully recovered patients.