Persistent COVID-19 Symptoms at 6 Months After Onset and the Role of Vaccination Before or After SARS-CoV-2 Infection
Authors: Richard Stephanie A. , Pollett Simon D. , Fries Anthony C. , Berjohn Catherine M. , Maves Ryan C. , Lalani Tahaniyat , Smith Alfred G. , Mody Rupal M. , Ganesan Anuradha , Colombo Rhonda E. , Lindholm David A. , Morris Michael J. , Huprikar Nikhil , Colombo Christopher J. , Madar Cristian , Jones Milissa , Larson Derek T. , Bazan Samantha E. , Mende Katrin , Saunders David , Livezey Jeffrey , Lanteri Charlotte A. , Scher Ann I. , Byrne Celia , Rusiecki Jennifer , Ewers Evan , Epsi Nusrat J. , Rozman Julia S. , English Caroline , Simons Mark P. , Tribble David R. , Agan Brian K. , Burgess Timothy H. ,   Epidemiology, Immunology, and Clinical Characteristics of Emerging Infectious Diseases With Pandemic Potential (EPICC) COVID-19 Cohort Study Group, Merritt Terry , Chambers Susan , Mount Cristin , Stein Michael , Uyehara Catherine , Adams Heidi , Hickey Patrick , Parmelee Edward , Fritschlanski Mark , Chao Tim , Chapleau Richard , Christian Monica , Lanter Kelsey , Meyer Jennifer , Iskander John , Lago Kathryn 
Published: January 2023

ImportanceUnderstanding the factors associated with post-COVID conditions is important for prevention.ObjectiveTo identify characteristics associated with persistent post–COVID-19 symptoms and to describe post–COVID-19 medical encounters.Design, Setting, and ParticipantsThis cohort study used data from the Epidemiology, Immunology, and Clinical Characteristics of Emerging Infectious Diseases With Pandemic Potential (EPICC) study implemented in the US military health system (MHS); MHS beneficiaries aged 18 years or older who tested positive for SARS-CoV-2 from February 28, 2020, through December 31, 2021, were analyzed, with 1-year follow-up.ExposuresSARS-CoV-2 infection.Main Outcomes and MeasuresThe outcomes analyzed included survey-reported symptoms through 6 months after SARS-CoV-2 infection and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnosis categories reported in medical records 6 months following SARS-CoV-2 infection vs 3 months before infection.ResultsMore than half of the 1832 participants in these analyses were aged 18 to 44 years (1226 [66.9%]; mean [SD] age, 40.5 [13.7] years), were male (1118 [61.0%]), were unvaccinated at the time of their infection (1413 [77.1%]), and had no comorbidities (1290 [70.4%]). A total of 728 participants (39.7%) had illness that lasted 28 days or longer (28-89 days: 364 [19.9%]; ≥90 days: 364 [19.9%]). Participants who were unvaccinated prior to infection (risk ratio [RR], 1.39; 95% CI, 1.04-1.85), reported moderate (RR, 1.80; 95% CI, 1.47-2.22) or severe (RR, 2.25; 95% CI, 1.80-2.81) initial illnesses, had more hospitalized days (RR per each day of hospitalization, 1.02; 95% CI, 1.00-1.03), and had a Charlson Comorbidity Index score of 5 or greater (RR, 1.55; 95% CI, 1.01-2.37) were more likely to report 28 or more days of symptoms. Among unvaccinated participants, postinfection vaccination was associated with a 41% lower risk of reporting symptoms at 6 months (RR, 0.59; 95% CI, 0.40-0.89). Participants had higher risk of pulmonary (RR, 2.00; 95% CI, 1.40-2.84), diabetes (RR, 1.46; 95% CI, 1.00-2.13), neurological (RR, 1.29; 95% CI, 1.02-1.64), and mental health–related medical encounters (RR, 1.28; 95% CI, 1.01-1.62) at 6 months after symptom onset than at baseline (before SARS-CoV-2 infection).Conclusions and RelevanceIn this cohort study, more severe acute illness, a higher Charlson Comorbidity Index score, and being unvaccinated were associated with a higher risk of reporting COVID-19 symptoms lasting 28 days or more. Participants with COVID-19 were more likely to seek medical care for diabetes, pulmonary, neurological, and mental health–related illness for at least 6 months after onset compared with their pre-COVID baseline health care use patterns. These findings may inform the risk-benefit ratio of COVID-19 vaccination policy.