Table 1. Hospitalization for Covid-19 and Test Positivity before and during the Proxy Omicron Period in Gauteng Province (September–December 2021).
| Vaccination Status | Comparator Period (September 1–October 31) |
Proxy Omicron Period (November 15–December 7) |
||||
|---|---|---|---|---|---|---|
| Tests Administered (N=133,437) |
Positive Test Results (N=8,569) |
Covid-19 Admissions (N=925) |
Tests Administered (N=78,173) |
Positive Test Results (N=19,070) |
Covid-19 Admissions (N=429) |
|
| number (percent) | ||||||
| Not vaccinated | 53,371 (40.0) | 5,231 (61.0) | 684 (73.9) | 26,331 (33.7) | 7,889 (41.4) | 220 (51.3) |
| BNT162b2 vaccine | ||||||
| One dose | 16,918 (12.7) | 1,279 (14.9) | 71 (7.7) | 6,185 (7.9) | 1,481 (7.8) | 34 (7.9) |
| <14 days after second dose | 5,200 (3.9) | 185 (2.2) | 13 (1.4) | 653 (0.8) | 114 (0.6) | 0 |
| ≥14 days after second dose | 38,155 (28.6) | 706 (8.2) | 77 (8.3) | 32,325 (41.4) | 6,290 (33.0) | 121 (28.2) |
| Other vaccine type* | 19,793 (14.8) | 1,168 (13.6) | 80 (8.6) | 12,679 (16.2) | 3,296 (17.3) | 54 (12.6) |
*
Data are based on a match with the national Electronic Vaccination Data System as of August 25, 2021, since such data were not available from the Department of Health regarding vaccine type and vaccinations administered in the public sector since that date. Thus, estimates of vaccine effectiveness should be viewed as conservative since unvaccinated controls may have inadvertently been included among vaccinated persons. On the basis of the number of Discovery Health patients who had been vaccinated in public-sector sites before August 25, 2021, the rate of misclassification of unvaccinated controls was estimated to be no more than 10%.