Table 2:
Linked serology analysis, showing the numbers of serology specimens and outcomes in each risk category, as well as logistic regression for the outcome of being a SARS-CoV-2 case, with and without severe disease. This analysis was adjusted for age category, sex, known comorbidities and subdistrict of residence.
| Logistic regression for the outcome of being a SARS-CoV-2 case, a non-severe case or having severe COVID-19 (admission/death) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| n | Cases | Admission or death | All cases | Non-severe cases | Admissions or death | ||||||||
| aOR | 95% CI | aOR | 95% CI | aOR | 95% CI | ||||||||
| 4th wave (Omicron) | Anti-N negative, no vaccination* | 607 | 16 | 7 | Ref | Ref | Ref | ||||||
| Anti-N negative, vaccinated (1 dose) | 95 | 1 | 0 | 0.41 | 0.05 | 3.18 | 0.73 | 0.09 | 5.89 | . | |||
| Anti-N negative, vaccinated (2 doses) | 450 | 12 | 5 | 0.87 | 0.40 | 1.90 | 1.00 | 0.36 | 2.78 | 0.64 | 0.19 | 2.12 | |
| Anti-N positive, no vaccination | 4,221 | 31 | 7 | 0.29 | 0.16 | 0.54 | 0.39 | 0.18 | 0.86 | 0.15 | 0.05 | 0.46 | |
| Anti-N positive, vaccinated (1 dose) | 883 | 22 | 0 | 0.97 | 0.50 | 1.92 | 1.61 | 0.72 | 3.62 | . | |||
| Anti-N positive, vaccinated (2 doses) | 1,928 | 11 | 2 | 0.22 | 0.10 | 0.47 | 0.33 | 0.13 | 0.85 | 0.07 | 0.01 | 0.35 | |
| 8,184 | 93 | 21 | |||||||||||
|
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| 3rd Wave (Delata) | Anti-N negative, no vaccination | 1,672 | 114 | 42 | Ref | Ref | Ref | ||||||
| Anti-N negative, vaccinated (1 dose) | 152 | 12 | 2 | 1.04 | 0.55 | 1.97 | 1.43 | 0.71 | 2.89 | 0.41 | 0.10 | 1.74 | |
| Anti-N negative, vaccinated (2 doses) | 85 | 0 | 0 | . | . | . | |||||||
| Anti-N positive, no vaccination | 4,066 | 18 | 1 | 0.08 | 0.05 | 0.13 | 0.10 | 0.06 | 0.18 | 0.02 | 0.00 | 0.11 | |
| Anti-N positive, vaccinated (1 dose) | 246 | 3 | 0 | 0.18 | 0.06 | 0.58 | 0.28 | 0.09 | 0.92 | . | |||
| Anti-N positive, vaccinated (2 doses) | 85 | 1 | 0 | 0.20 | 0.03 | 1.49 | 0.37 | 0.05 | 2.75 | . | |||
| 6,306 | 148 | 45 | |||||||||||
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| 2nd wave (Beta) | Anti-N negative, no vaccination | 1,385 | 38 | 16 | Ref | Ref | Ref | ||||||
| Anti-N positive, no vaccination | 1,866 | 6 | 2 | 0.13 | 0.05 | 0.31 | 0.15 | 0.05 | 0.45 | 0.10 | 0.02 | 0.45 | |
| 3,251 | 44 | 18 | |||||||||||
Vaccination was assessed at time of SARS-CoV-2 diagnosis, or if no diagnosis was made, at the peak of the relevant wave. “Vaccinated (2 doses)” was defined as being >14 days after a second dose of Pfizer–BioNTech (BNT162b2), while “vaccinated (1 dose)” refers a single dose of Pfizer or Janssen/Johnson & Johnson (Ad26.COV2.S). Third doses of vaccination were not widely available at the time of serology testing and therefore not assessed in this study.