Long-Term Study of COVID-19 Infection and Long COVID

Longitudinal Study of Patients With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection and Post-Acute Sequelae of COVID-19 (PASC)

This study will examine how common Long COVID is and how symptoms may persist over time in people who have previously had COVID-19. Researchers will collect information about participants' health and symptoms through questionnaires and may collect saliva and other non-invasive oral samples. The study will also examine biological factors in these samples that may be associated with persistent symptoms. The goal is to better understand why some people develop Long COVID and identify factors that may help predict who is more likely to experience persistent symptoms.

Post-Acute Sequelae of COVID-19 (PASC), also known as Long COVID, is characterized by persistent or newly developed symptoms following SARS-CoV-2 infection. The biological mechanisms underlying persistent symptoms remain incompletely understood, particularly among individuals experiencing symptoms more than two years after infection.

This observational study will evaluate individuals with a history of SARS-CoV-2 infection to characterize the prevalence, severity, and persistence of PASC symptoms and identify demographic, clinical, and biological factors associated with these outcomes. Participants will complete questionnaires about their health and symptoms and provide saliva specimens for biological analyses.

Saliva will be evaluated for biological factors that may be associated with persistent symptoms, including proteins, metabolites, microorganisms, and immune-related markers.

Machine learning approaches will be used to integrate demographic, clinical, symptom, and saliva-based biological data to identify patterns associated with PASC. The study will evaluate whether these combined characteristics can be used to identify individuals who are more likely to experience persistent or severe symptoms following SARS-CoV-2 infection. The resulting models may help identify factors that contribute to Long COVID risk and inform future approaches for predicting persistent symptoms.

The study will include both newly enrolled participants and participants who previously participated in related SARS-CoV-2 research. Findings from this study may improve understanding of Long COVID and the factors associated with persistent symptoms following SARS-CoV-2 infection.

Inclusion Criteria:

• Age 18 to 75 years.
• Previous laboratory-confirmed SARS-CoV-2 infection.
• Willing and able to provide informed consent.
• Able to complete study questionnaires and study procedures.

Exclusion Criteria:

• Current severe periodontal disease with bleeding gums.
• Current oral herpes flare, aphthous ulcer, or oral candidiasis (thrush).
• Oral viral or bacterial infection within the previous 30 days.
• Dry mouth that would prevent adequate saliva collection.
• Active alcohol or drug abuse.
• Medical or genetic syndrome or developmental delay that would prevent completion of study procedures or questionnaires.