Table 2

SARS-CoV-2 IgG seropositivity by study group

Study groupTotalIgG positive
Group 1*9972 (72.7)
Group 2†1062 (1.9)
Group 3‡911 (1.1)
Group 4§1001 (1.0)
Group 5¶1072 (1.9)
Total50378 (15.5)
  • Data are presented as n (%) or total in first column.

  • *RT-PCR-confirmed COVID-19 infection (>1 month postpositive RT-PCR).

  • †Close contacts of persons with COVID-19 infection and who subsequently developed symptoms (virus not detected by RT-PCR on oropharyngeal/nasopharyngeal swab).

  • ‡Close contacts of COVID-19 cases and who remained asymptomatic.

  • §HCWs working in areas determined as high-risk clinical areas.

  • ¶HCWs working in areas determined as low-risk clinical areas.

  • HCW, healthcare worker; RT-PCR, real-time PCR.