Table 1

Demographic data

First study visit (May/June)Second study visit (September/October)
StudentsTeachersStudentsTeachers
Participants1538 (75.2%)507 (24.8%)1334 (75%)445 (25%)
Age (median)15 (14–16)51 (37–57)15 (14–16)50 (36–57)
Woman802 (52%)357 (70%)680 (51%)313 (70%)
Household size4 (3–5)2 (2–4)4 (3–5)2 (2–4)
Seropositive111111
Regular social contacts outside the student’s household/classroom during the March 2020 lockdown1230 (80%)
Respiratory symptoms between study visits587 (44%)71 (16%)
Febrile illness between study visits67 (5%)4 (0.9%)
  • Demographic and clinical characteristics at baseline and follow-up. Data are presented as numbers with percentages except for age, which is presented as median with IQR.