Fig. 1: Schedule of blood sampling relative to vaccine administration.

Participants were asked to provide a blood sample before their first and second vaccine doses as well as blood samples during two follow-up visits, anchored around 30 and 60 days, respectively, after their second dose of the 2-dose vaccine series. Target windows depicted in this diagram are inclusive of both the different schedules for Pfizer-BioNTech (+21 day) and Moderna (+28) second doses as well as a 7-day buffer granted to participants for scheduling convenience, participants arriving outside of this schedule were included if their blood draws fell within the wider windows for follow-up depicted here. Baseline data are referred to as “day 0” throughout, including when the data are presented graphically.