TABLE. Relative risk and estimated vaccine effectiveness for prevention of SARS-CoV-2 infection, symptomatic COVID-19, hospitalization, and death for fully vaccinated persons compared with unvaccinated persons during a COVID-19 outbreak in a skilled nursing facility (SNF) — Kentucky, 2021.
| Population and outcome | No. (% attack rate) |
Unvaccinated versus vaccinated RR (95% CI) | Vaccine effectiveness§ (95% CI) | |
|---|---|---|---|---|
| Vaccinated* | Unvaccinated† | |||
|
Total SNF population¶
|
(n = 127)
|
(n = 62)
|
— |
— |
| SARS-CoV-2 infection |
22 (17.3) |
22 (35.5) |
— |
— |
| Symptomatic |
8 (6.3) |
20 (32.3) |
— |
— |
| Hospitalization |
2 (1.6) |
4 (6.5) |
— |
— |
| Death |
1 (0.8) |
2 (3.2) |
— |
— |
|
Residents
|
(n = 71)
|
(n = 8)
|
— |
— |
| SARS-CoV-2 infection |
18 (25.4) |
6 (75.0) |
3.0 (1.7–5.2) |
66.2 (40.5–80.8) |
| Symptomatic |
6 (8.5) |
5 (62.5) |
7.4 (2.9–18.8) |
86.5 (65.6–94.7) |
| Hospitalization |
2 (2.8) |
4 (50.0) |
17.8 (3.8–82.1) |
94.4 (73.9–98.8) |
| Death |
1 (1.4) |
2 (25.0) |
17.8 (1.8–174.7) |
94.4 (44.6–99.4) |
|
Health care personnel
|
(n = 56)
|
(n = 54)
|
— |
— |
| SARS-CoV-2 infection |
4 (7.1) |
16 (29.6) |
4.1 (1.5–11.6) |
75.9 (32.5–91.4) |
| Symptomatic |
2 (3.6) |
15 (27.8) |
7.8 (1.9–32.4) |
87.1 (46.4–96.9) |
| Hospitalization |
0 (—) |
0 (—) |
— |
— |
| Death | 0 (—) | 0 (—) | — | — |
Abbreviations: CI = confidence interval; RR = relative risk.
* Receipt of 2 doses of Pfizer-BioNTech vaccine ≥14 days before identification of the SNF outbreak; persons who received a second dose of vaccine <14 days before the outbreak (four residents and five health care personnel) and those who received a single dose of vaccine (one health care worker) were excluded, which resulted in exclusion of two resident cases.
† Receipt of zero doses of COVID-19 vaccine.
§ Calculated as (1−RR of vaccinated versus unvaccinated) x100.
¶ Includes residents and health care personnel.