Characteristics of long COVID and the impact of COVID-19 vaccination on long COVID 2 years following COVID-19 … – Nature.com

Study participants and design

This prospective cohort study enrolled adult patients in Korea with polymerase chain reaction-confirmed COVID-19 infection between February 17, 2020, and March 24, 2020, and data were collected between August 31, 2020, and March 29, 2022. Initially, 5,252 adult patients with COVID-19 infection were identified from the Daegu Center for Infectious Disease Control and Prevention registry in Daegu and contacted individually by mobile phone. After excluding deceased patients, we included those who agreed to participate and were able to visit the study hospital. Patients were recruited to be evenly distributed by age to reduce age-related bias.

Participants visited Kyungpook National University Hospital four times in the 24months following the onset or diagnosis of COVID-19. Enrolled patients were those who consented to participate and completed all four hospital visits. A survey was conducted using a modified version of the International Severe Acute Respiratory and Emerging Infection Consortium protocol, translated into Korean22 (Supplementary Table S1). Long COVID was defined by 38 symptoms: fever, chills, myalgia, arthralgia, fatigue, cough, sore throat, rhinorrhea, sputum production, dyspnea, palpitations, arrhythmia, chest discomfort, headache, dizziness, cognitive dysfunction, difficulty concentrating, amnesia, abnormal directional sensibility, seizure, paresthesia, globus pharyngeus, hallucination, insomnia, social phobia, depression, anxiety, obsessive thinking, anorexia, diarrhea, nausea or vomiting, anosmia, ageusia, tinnitus, alopecia, skin rashes, pruritis, and COVID toes.

The survey included questions on the following: sex, birth date, COVID-19 diagnosis date, COVID-19 symptom onset date, height, weight, smoking history, quarantine site during acute COVID-19 infection, oxygen treatment history including ventilator usage, extracorporeal membrane oxygenation (ECMO), dialysis at the time of hospitalization, intensive care unit admission history, COVID-19 vaccination history, underlying diseases, symptoms or diseases newly identified after COVID-19 infection, hospitalization history after acute COVID-19 infection, and COVID-19 reinfection history. Disease severity during acute COVID-19 infection was classified into five categories ranging from asymptomatic to critical illness. Clinical data, including symptoms and disease severity during acute COVID-19 infection, was confirmed using the Daegu Center for Infectious Disease Control and Prevention registry.

Long COVID was defined as having at least one newly identified intermittent or continuous symptom 3months after the initial SARS-CoV-2 infection, lasting for at least 2months, with no other explanation23. Vaccination was considered complete in patients after at least (a) 2weeks after receiving the second dose in a two-dose COVID-19 vaccine series or (b) 2weeks after receiving a single dose COVID-19 vaccine.

The study investigated the clinical characteristics of long COVID and the impact of vaccination on long COVID symptoms, focusing on quality of life and mental health using several scales. These included the EuroQol 5-dimension 5-level (EQ5D) tool, Korean version of the Patient Health Questionnaire-9 (PHQ-9), the Generalized Anxiety Disorder-7 (GAD-7) scale, and the Post-Traumatic Stress Disorder (PTSD) Checklist-5-Korean version (PCL-5-K) scores. The EQ5D score comprises five categories: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each category has five levels to indicate the severity of problems (none, slight, moderate, severe, and extreme). Respondents indicated their health status by selecting the most appropriate statement for each category. The scores for the five categories were then combined to form a five-digit number representing the respondents health status24. PHQ-9 is an instrument for screening, diagnosing, monitoring, and measuring the severity of depression. PHQ-9 scores were rated using a four-point Likert scale ranging from 0 (not at all) to 3 (nearly every day). Total score can range from 0 to 27, with high scores indicating more severe depression. Based on the original validation studies, the total score is then interpreted to represent no (04), mild (59), moderate (1014), moderately severe (1519), or severe (2027) depression. A cutoff score of 10 suggests a possible diagnosis of depressive disorder25. The GAD-7 is a seven-item self-reported instrument with each item scored on a four-point Likert scale indicating symptom frequency, ranging from 0 (not at all) to 3 (nearly every day). Total scores represent none/minimal (05), mild (610), moderate (1115), and severe (>16) anxiety symptoms. The GAD-7 score can range from 0 to 21, with a score10 indicative of generalized anxiety disorder25. The PCL-5-K consists of five, single-factor items scored dichotomously as either yes (1 point) or no (0 points). Higher scores indicate more severe symptoms, and 3 is the cutoff score for significant PTSD26. In addition to using these standardized scales, we also evaluated other changes in lifestyle habits potentially related to long COVID.

Descriptive statistics were used to assess demographic differences. Other categorical and noncategorical variables were compared using Fishers exact test, chi-square test, Students t-test, or MannWhitney U test as appropriate. Clinical characteristics were compared between the symptomatic group and asymptomatic group at 24months following acute COVID-19 infection to identify the factors affecting thedevelopment of long COVID. The frequency of each long COVID symptom was calculated at 6, 12, 18, and 24months following acute COVID-19 infection and shown as a percentage of the respondents. In addition, we conducted univariate analysis to identify the impact of vaccination on long COVID symptoms. The score distributions from PHQ-9, GAD-7, and PCL-5-K scales were compared between 12-month and 24-month timepoints after acute infection to identify the long-term impact of COVID-19 on psychiatric symptoms. The PHQ, GAD-7, and PCL-5-K scores at 12, 18, and 24months after acute COVID-19 infection were analyzed with respect to disease severity, using violin plots to show the distribution and peak of the scores from each scale. Furthermore, Sankey flow diagrams were generated to identify changes in the distribution and interaction of major long COVID symptoms over time. For all tests, differences were considered statistically significant at P<0.05. R Statistics version 4.0.2 was used for all statistical analyses (The R Foundation; https://www.r-project.org).

This study was reviewed and approved by the Institutional Review Board of Kyungpook National University Hospital (approval no.: 202102-003). All methods were performed in accordance with the relevant guidelines and regulations by including a statement in the methods section. All respondents provided digital informed consent before the questionnaire was administered.

Read the original here:

Characteristics of long COVID and the impact of COVID-19 vaccination on long COVID 2 years following COVID-19 ... - Nature.com