Table 1 Characteristics of the study participants
SARS-CoV-2 infection and vaccination status at follow-up | ||||
|---|---|---|---|---|
Characteristics | 2 doses (N = 11) | 2 doses + infection (N = 11) | 3 doses (N = 11) | P |
Women | 6 (55) | 6 (55) | 6 (55) | 1.00 |
Age, years | 25 [24–30] | 26 [24–29] | 27 [25–29] | 0.61 |
Body mass index, kg/m2 | 21 [18–21] | 21 [20–22] | 21 [19–24] | 0.44 |
Job | ||||
Doctor | 3 (27) | 1 ( 9) | 2 (18) | 0.65 |
Nurse | 6 (55) | 6 (55) | 8 (73) | |
Allied health professionals | 2 (18) | 2 (18) | 1 ( 9) | |
Others | 0 ( 0) | 2 (18) | 0 ( 0) | |
COVID-19 related work | 6 (55) | 5 (45) | 4 (36) | 0.90 |
Intervals between vaccinations, infection, and surveys | ||||
Second dose to baseline, days | 67 [40–74] | 63 [39–71] | 70 [67–73] | 0.30 |
Second dose to follow-up, days | 243 [221–251] | 247 [218–250] | 252 [249–256] | 0.02 |
Baseline to follow-up, days | 178 [177–181] | 182 [179–184] | 183 [181–187] | 0.02 |
Third dose to follow-up, days | – | – | 10 [8–10] | |
Second dose to infection a, days | 124 [119–140] | |||
Baseline to infection a, days | 56 [53–65] | |||
Infection to follow-up a, days | – | 126 [113–130] | – | |
SARS-CoV-2 antibody titers at baseline | ||||
Spike IgG antibody (Abbott), AU/mL | 3,671 [2,640 − 10,161] | 3,739 [2,435-9,555] | 3,811 [2,306-9,812] | 0.99 |
Total antibody (Roche), AU/mL | 1,282 [915-1,892] | 935 [762-1,260] | 1,258 [826-2,099] | 0.34 |
NAb (Wuhan), NT50 | 290 [139–372] | 234 [85–381] | 182 [40–308] | 0.44 |
NAb (Delta), NT50 | 168 [49–206] | 101 [42–162] | 76 [47–220] | 0.74 |
NAb (Omicron BA.1), NT50 | All < 40 | All < 40 | All < 40 | – |
PCR-confirmed COVID-19 cases at follow-up | 0 (0) | 0 (0) | 7 (64) | – |
Seropositive against SARS-CoV-2 nucleocapsid protein at follow-up | 0 (0) | 11 (100) | 0 (0) | – |
Symptoms of breakthrough cases b | ||||
Symptomatic | – | 7 (64) | – | – |
Asymptomatic | – | 4 (36) | – | – |
Type of SARS-CoV-2 strain c | ||||
Delta | – | 4 (57) | – | – |
Unknown (unmeasured) | – | 3 (43) | – | – |