Symptom science and post-COVID-19 conditions

The prolonged symptoms and health problems that occur after acute coronavirus disease 2019 (COVID-19) are called post-COVID-19 conditions. Studies have reported different symptoms of post-COVID-19 conditions based on the person’s exposure to the type of severe acute respiratory syndrome coronavirus (SARS-CoV-2) variant. While limited interventions are currently available, clinicians can use the Symptom Science Model (SSM) 2.0 to investigate symptoms and treatments in individuals suffering from post-COVID-19 conditions. In this commentary, we will discuss post-COVID-19 conditions using the original National Institutes of Health (NIH) Symptom Science Model (SSM) and the expanded SSM 2.0. Studying post-COVID-19 conditions using the four-step investigative sequence (complex symptoms, phenotype, biobehavioral factors, and clinical applications) provides a comprehensive understanding of disease to develop personalized and precise interventions. The revised model includes social determinants of health, patient-centered experience, and policy and population health components that provide a more holistic approach to examining symptoms and symptom clusters. Post-COVID-19 conditions should be studied using the inclusive approach of the SSM 2.0 to better understand the complex symptoms, phenotypic presentation, and biobehavioral factors and develop new treatments to reduce symptom burden. More than 4 years into the COVID-19 pandemic, millions of individuals worldwide still suffer from post-COVID-19 conditions. Thus, more investigations are needed to understand this infection-associated chronic illness and provide potential interventions to improve public health and quality of life.