Table 1.

Study schedule

		Study period
	Eligibility	Enrollment, randomization and vaccination	Post-randomization
Time point	Approximately 12 weeks	Day 0	Week 4	Week 12 (± 7 days)	Week 48 (± 7 days)	Continuous follow-up in the frame of the cohort
Enrollment:
Eligibility screena	Xa
Eligibility assessment	X
Informed consent		Xa
Allocation		Xb
Interventions:
Intervention COVID-19 mRNA Vaccine Moderna®		X	X
Control Comirnaty® (Pfizer/BioNTech vaccine)		X	X
Assessments:
Baseline variables (will be exported from routine cohort data)Baseline blood sample	X
IgG neutralizing antibodies post randomization but prior to vaccination		X
Clinical outcomes:	Xe	Xe
- Immune response IgG neutralizing antibodies		X		xc
- Newly confirmed asymptomatic SARS-CoV-2 infection				xc	xc,d	xd
-Newly confirmed symptomatic SARS-CoV-2 infection				xc	xc,d	xd
- Severe COVID-19 infection with respiratory failure, evidence of shock, organ failure, admission to ICU, or death				xc	xc,d	xd
- Adverse events from vaccines				xc
-Serious adverse events			xc,d	xc	xc,d	xd
- PCR confirmed symptomatic infections of household members				xc	xc.d	xd

^aContinuous assessment and selection from routinely collected cohort data

^bEnrollment and concealed allocation of patients with informed consent will be performed during the same visit when the study is explained to the patient or, if preferred, during a separate arranged study visit. Not all study centers will have both vaccines available at each vaccination day. This probably requires us to randomize some patients as soon as they give consent to a specific vaccination day on which their allocated vaccination will be applied some days before applying the vaccine

^cAssessed in separate data entry form for the trial

^dAssessed by routine data collection from cohort data base

^eBaseline blood samples will be taken from previous cohort visits (no longer than 6 months) or during cohort and randomization visits at day 0