622 RESEARCH Turkish Journal of Geriatrics DOI: 10.31086/tjgeri.2022.321 2022; 25(4): 622-631 CORRESPONDANCE 1 Bakirkoy Dr Sadi Konuk Training and Research Hospital, Infectious Diseases and Clinical Microbiology, Istanbul, Turkey 2 Haseki Training and Research Hospital, Infectious Diseases and Clinical Microbiology, Istanbul, Turkey 3 Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Infectious Diseases and Clinical Microbiology, Istanbul, Turkey 4 Bakirkoy District Health Directorate, Public Health, Istanbul, Turkey COMPARISON OF CLINICAL OUTCOMES OF CORONAVAC VACCINATED AND UNVACCINATED OLDER ADULTS WITH HOSPITALIZED COVID-19 RESEARCH  Yusuf Emre ÖZDEMİR 1 . . . . . . . . .  Muhammet Salih TARHAN 1 . . . . . .  Burak KIZILÇAY 1 . . . . . . . . . . . . . .  Müge SÖNMEZIŞIK 1 . . . . . . . . . . .  Esra CANBOLAT ÜNLÜ 1 . . . . . . . .  Deniz BORÇAK 1 . . . . . . . . . . . . . .  Serkan SÜRME 2 . . . . . . . . . . . . . .  Meryem ŞAHİN ÖZDEMİR 3 . . . . . .  Osman Faruk BAYRAMLAR 4 . . . . .  Zuhal YEŞİLBAĞ 1 . . . . . . . . . . . . .  Sevtap ŞENOĞLU 1 . . . . . . . . . . . .  Habip GEDİK 1 . . . . . . . . . . . . . . . .  Kadriye KART YAŞAR 1 . . . . . . . . . 1 Yusuf Emre ÖZDEMİR Phone : +902124147171 e-mail : dryusufeozdemir@gmail.com Received : Aug 29, 2022 Accepted : Nov 30, 2022 Introduction: We aimed to compare the COVID-19 outcomes in unvaccinated and CoronaVac vaccinated older adults. Materials and Method: In this single-center study, patients aged ≥65 years who were hospitalized for COVID-19 were retrospectively analyzed in two groups: unvaccinated and vaccinated. Results: A total of 742 patients were included. The mean age was 76.6±7.6 years. Of these, 46.1% (n=342) were male, 76.0% (n=564) were vaccinated. Among patients who were transferred to the intensive care unit (n=217), 206 (27.8%) received invasive mechanical ventilation support and 194 (26.1%) were died. In the multivariate analysis, advanced age (OR=1.03, 95%CI=1.01-1.06, p<0.01) and a high Charlson Comorbidity Index (OR=1.24, 95%CI=1.12-1.38, p<0.01) were predictors of mortality, while being vaccinated (OR=0.75, 95%CI=0.62- 0.91, p<0.01) was associated with survival. Vaccination reduced the need for intensive care by 26.5% and mortality by 24.9 %. When the vaccinated group was evaluated, high Charlson Comorbidity Index (OR=1.428, 95%CI=1.14- 1.64, p<0.01) was an independent predictor for mortality. However, booster vaccination in the last 130 days was the only protective factor that reduced mortality (p=0.04, 95%CI=0.43-0.99, OR=0.66) in multivariate analysis. Booster dose vaccination in the last 130 days reduced mortality by 33.8%. Conclusion: CoronaVac vaccination improved survival in hospitalized older adult patients (≥65 years old) with COVID-19. However, delaying the booster dose for more than 130 days were significantly associated with decreased survival. Therefore, older adults who completed their primary vaccination series with CoronaVac should not delay their booster dose to reduce the risk of death. Keywords: COVID-19; Aged; Death; Vaccination. ABSTRACT