Table 4. Variables associated with COVID-19 hospitalization: Cox regression analysis, Islamic Republic of Iran, 2021.
| Independent variable | HR (95% CI) |
|
|---|---|---|
| Partial immunity perioda | Full immunity periodb | |
| Age, years | 1.03 (1.02–1.04) | 1.03 (1.02–1.04) |
| Female sex | 1.02 (0.82–1.26) | 0.98 (0.74–1.28) |
| Education, years | 1.02 (0.997–1.047) | 1.02 (0.99–1.05) |
| Vaccine brand | ||
| SARS-CoV-2 Vaccine (Vero Cell), Inactivated (lnCoV) | Reference | Reference |
| Sputnik V | 0.62 (0.38–1.00) | 0.86 (0.46–1.59) |
| AZD1222 Vaxzevria | 0.47 (0.36–0.61) | 0.71 (0.48–1.08) |
| CovIran® vaccine | 0.91 (0.62–1.32) | 1.16 (0.73–1.84) |
| Prior COVID-19 infection | 0.42 (0.29–0.62) | 0.66 (0.44–1.00) |
| Chronic respiratory diseases | 1.96 (1.21–3.19) | NAc |
| Chronic renal diseases | 2.05 (1.14–3.68) | 2.52 (1.33–4.80) |
| Chronic cardiac diseases | 1.38 (1.00–1.92) | NAc |
| Diabetes | 1.63 (1.23–2.16) | 1.75 (1.25–2.44) |
| Obesity | 1.60 (1.22–2.11) | NAc |
CI: confidence interval; COVID-19: coronavirus disease 2019; HR: hazard ratio; NA: not applicable.
a Defined as the period between the 14th day after the first dose and 14 days after the second dose.
b Defined as the period between the 14th day after the second dose and the end of follow-up.
c Not entered in the final stepwise Cox regression models as P ≥ 0.1 in the univariate analysis.