Table 1.
Comparison of characteristics between vaccinated and unvaccinated healthcare workers with COVID-19.
| All HCWs (n = 55) | Non-vaccinated (n = 31) | Vaccinated (n = 24)a | p | |
|---|---|---|---|---|
| Age (years), mean (SD) | 42.3 (9.9) | 43.1 (9.8) | 41.3 (10.1) | .5269 |
| Male gender, n (%) | 14 (25.5) | 6 (19.4) | 8 (33.3) | .3502 |
| Likely hospital acquisition, n (%)b | 31 (79.5) | 17 (77.3) | 14 (82.4) | 1 |
| Acquisition by household contact, n (%) | 8 (20.5) | 5 (22.7) | 3 (17.6) | 1 |
| Day of diagnosis post exposure, median (IQR) | 5 (4.8–7) | 5.5 (5–7) | 4.5 (4–5) | .2796 |
| Day of positive PCR from symptom start, median (IQR) | 1 (0–2) | 2 (1–2.8) | 1 (0–1.3) | .0926 |
| Ct values, median (IQR) | 18.5 (15–25.3) | 18.5 (13.5–24) | 18.5 (16–26)c | .6957 |
| Strain B.1.1.7 | 54 (98.2)d | 30 (96.8) | 24 (100) | 1 |
| Hospital admissione | 2 (3.6%) | 2 (6.5%) | 0 (0%) | .4990 |
| Any symptom | 42 (76%) | 23 (75%) | 19 (79%) | .7561 |
| Cough, n (%) | 16 (29.1) | 12 (38.7) | 4 (16.7) | .1332 |
| Nasal congestion, n (%) | 15 (27.3) | 2 (6.5) | 13 (54.2) | .0001 |
| Rhinorrhea, n (%) | 7 (12.7) | 1 (3.2) | 6 (25) | .0352 |
| Sore throat, n (%) | 16 (29.1) | 9 (29) | 7 (29.2) | 1 |
| Fever or low-grade fever, n (%) | 9 (16.4) | 7 (22.6) | 2 (8.3) | .2713 |
| Anosmia/ ageusia, n (%) | 1 (1.8) | 0 (0) | 1 (4.2) | .4364 |
Ct: cycle threshold; HCWs: healthcare workers; IQR: interquartile range; SD: standard deviation.
an = 3 partially vaccinated (1 dose, 10, 20 and 22 days before the positive PCR), n = 14 completely vaccinated (2 doses and at least 2 weeks from last vaccination). bMost (44/45) identified from 28 March to 14 April 2021 during an in-hospital outbreak. cExcluding the 3 partially vaccinated cases, the median Ct value was 18 (IQR = 15.5-25.5). No difference in the statistical significance of these results occurred when these 3 partially vaccinated cases were excluded, with the exception of cough. dThere was one non-vaccinated patient infected with the strain B.1.177. eUntil May 12.