Table 1.
Demographic and clinical characteristics of nursing home residents involved in the three post-vaccination outbreaks
| Characteristics | Nursing home A Delta | Nursing home B Gamma | Nursing home C Mua |
|---|---|---|---|
| Median age, years (range) | 87 (63–102) | 82 (59–98) | 87 (64–103) |
| Sex, number (%) | |||
| Male | 71 (26.5%) | 11 (23.9%) | 77 (25.2%) |
| Female | 197 (73.5%) | 35 (76.1%) | 229 (74.8%) |
| Start vaccinating residents | 8 Jan 2021 | 12 Jan 2021 | 26 Jan 2021 |
| Vaccination ratio (among PCR+) | |||
| 2 doses | 96% (94.6%) | 86.2% (89.5%) | 98.0% (100%) |
| 1 dose | 1% (1.4%) | 13.0% (10.5%) | 0.4% (0%) |
| 0 doses | 3% (4.1%) | 0% | 1.3% (0%) |
| First documented case | 17 May 2021 | 20 May 2021 | 20 July 2021 |
| PCR positivity | 62.5% (75/120) | 65.5% (19/29) | 12.0% (20/166) 69.0% (20/29)d |
| Case fatality ratio (only PCR+) | 20.0% (15/75)b | 31.6% (6/19)c | 35.0% (7/20)b |
aFor nursing home C, three isolated Delta cases were observed in addition to the Mu outbreak. All residents received the Comirnaty (Pfizer) vaccine.
bAn additional resident died, not SARS-CoV-2 PCR positive, with death considered not COVID-19 related.
cA total of seven fatal cases, of which one was not SARS-CoV-2 PCR positive; this death was classified as COVID-19 related due to severe respiratory symptoms and recent close contact with positive residents, according to WHO criteria16.
dConsidering only the 29 residents of the two affected wards, positivity rates increase up to 69.0%.