Table 1 Summary of the variables collected in the baseline and follow-up questionnaires

Sociodemographic information

Demographics and socio-economic questions

X

X

X

Change in employment and income status following the COVID-19 infection

X

COVID-19 variables

Date of positive COVID-19 test

X

List of potential acute COVID-19 symptoms (yes / no)

X

X

Perceived recovery from COVID-19 infection from 1 (not at all) to 5 (completely)

X

List of potential medical complications of COVID-19 infection (yes / no)

X

List of potential post COVID-19 symptoms (yes / no)

X

Shortness of breath

Medical Research Council (MRC) dyspnea scale

X

X

Fatigue

Visual Analogue Scale for Fatigue from 0 (no fatigue) to 10 (very severe fatigue)

X

X

Vaccination

COVID-19 vaccination (yes / no)

X

X

Number of doses and date of last dose

X

X

List of the different vaccines offered in Belgium (last vaccine received)

X

X

Health-related quality of life

Modified EQ-5D (EuroQol Group)

X

X

X

Functional limitations

Washington city group (WCG)

X

X

X

Global Activity Limitation Indicator (GALI)

X

X

Mental health and wellbeing

General Anxiety Disorder-7 (GAD-7)

X

X

X

Patient Health Questionnaire-9 (PHQ-9)

X

X

X

Visual Analogue Scale for Life Satisfaction from 0 (not at all satisfied) to 10 (totally satisfied)

X

X

X

Social health

UCLA Three-Item Loneliness Scale

X

X

X

Health history and behaviours

List of potential chronic diseases (yes / no)

X

X

Mental health problem before COVID-19 infection (yes / no)

X

Tobacco smoking (frequency, quantity, number of years)

X

X

Physical activity (frequency, duration)

X

X

Food (consumption of fruits and vegetables, frequency)

X

X

Body Mass Index

X

X

Pregnancy (yes / no, if yes trimester)

X

X

Since the COVID-19 infection change in the consumption of fruit and vegetables, alcohol, tobacco, sedatives, antidepressants (intensity)

X

Since the COVID-19 infection change in physical activity habits (intensity)

X

Health care use

Hospitalisations since COVID-19 infection (type, number, duration)

X

Consultations with healthcare professionals since COVID-19 infection (type, number)

X

Diagnosis of post COVID-19 condition by a healthcare professional (yes / no)

X