Figure 1.

Flowchart of cohort creation, study of side effects after COVID-19 vaccination with Comirnaty, Israel, December 2020–March 2021 (n = 1,213,693)

COVID-19: coronavirus disease; MHS: Maccabi Healthcare Services.

^a Inclusion criteria were age 18–85 years, a valid cell phone number or email in the MHS systems and no prior refusal to participate in electronic surveys.

^b 72,392 individuals filled the first and the second survey.