Luxembourg Cohort of Positive Patients for COVID-19: a Stratification Study to Predict Patient Prognosis

The objective is to recruit virtually all COVID-19 positive persons in Luxembourg.

The sub-sample of a minimum of 200 COVID-19 positive persons in Predi-COVID study would allow to find a risk ratio of severe disease above 2 for the selected risk factor with a power of 80% when the prevalence of the disease is above 7%.

For every symptomatic adult tested positive by RTqPCR, biological samples will be collected at the inclusion and as follow-up 3 weeks after inclusion.

For patients at home, an experienced nurse from CIEC will perform the sampling, using all the required precautions and protections in the actual context.

For hospitalised patients, a simplified sampling strategy will be put in place and adapted to the patient state, the workload of staff and adapted constantly depending on the evolution of the epidemy.

Data will be collected through 3 different ways :

• Questionnaires : health status monitoring data with daily questionnaires during the 14 first days following diagnosis, weekly questionnaires at week 3 and 4 and monthly questionnaires from month 2 to month 12.
• Adapted ISARIC eCRF for patients at hospital (during all hospital stay) and at inclusion for patients included from home.
• Smartphone application (LIH in-house solution) : innovative data (voice recordings, geolocation and mini-questionnaires).

An ancillary study will be added (Predi-COVID-H):

Predi-COVID-H is an ancillary cohort study composed of Household members of index cases to monitor symptoms and disease outbreak in this high-risk population. For every asymptomatic member of the family of a "case" included in the Predi-COVID sub-sample (a "contact"), clinical as well as socio-economic characteristics will be collected. Biological samples will also be collected at the same time as the "case" visit by nurses and up to 30 ml of blood will be taken at baseline, for serology. IgG and/or IgA seropositive "contacts" will be proposed to be enrolled in the Predi-COVID study. For IgG and IgA seronegative "contacts", a second serology will be planned 2 weeks later, up to 30 mL of blood will be collected. If they become IgG and/or IgA seropositive, they will be proposed to be enrolled in the Predi-COVID study. IgG and IgA seronegative "contacts" will be followed digitally

Inclusion criteria

• SARS-CoV-2 infection as determined by PCR, performed by one of the certified laboratories in Luxembourg
• Signed informed consent form
• Age ≥18 years old
• Hospitalized or at home

Exclusion criteria

• Patients not understanding French or German
• Patients already included in an interventional study on Covid-19 (Discovery or other)