Effectiveness of different vaccine platforms in reducing mortality and length of ICU stay in severe and critical cases of COVID‐19 in the Omicron variant era: A national cohort study in Iran

Abstract

Various severe acute respiratory syndrome coronavirus 2 vaccines with different platforms have been administered worldwide; however, their effectiveness in critical cases of COVID‐19 has remained a concern. In this national cohort study, 24 016 intensive care unit (ICU) coronavirus disease‐2019 (COVID‐19) admissions were included from January to April 2022. The mortality and length of ICU stay were compared between the vaccinated and unvaccinated patients. A total of 9428 (39.25%) patients were unvaccinated, and 14 588 (60.75%) patients had received at least one dose of the vaccine. Compared with the unvaccinated, the first, second, and third doses of vaccine resulted in 8%, 20%, and 33% lower risk of ICU mortality in the adjusted model, with risk ratio (RR): 0.92, 95% confidence interval (CI): 0.84–1.001, RR: 0.80, 95% CI: 0.77–0.83, and RR: 0.67, 95% CI: 0.64–0.71, respectively. The mean survival time was significantly shorter in the unvaccinated versus the fully vaccinated patients (hazard ratio [HR]: 0.84, 95% CI: 0.80–0.88); p < 0.001). All vaccine platforms successfully decreased the hazard of ICU death compared with the unvaccinated group. The duration of ICU stay was significantly shorter in the fully vaccinated than in unvaccinated group (MD, −0.62, 95% CI: −0.82 to −0.42; p < 0.001). Since COVID‐19 vaccination in all doses and platforms has been able to reduce the risk of mortality and length of ICU‐stay, universal vaccination is recommended based on vaccine availability.

Effectiveness of the SARS-CoV-2 Vaccination in Preventing Severe Disease-Related Outcomes: A Population-Based Study in the Italian Province of Bolzano (South Tyrol)

“…Furthermore, our results evidenced a shorter LoS for vaccinated patients compared to unvaccinated patients, suggesting a more rapid attenuation of severe symptoms, and providing insight for future research on an aspect that is still understudied and the subject of scientific debate [ 39 , 40 ]. Overall, this study contributes valuable information to the existing literature.…”

Booster vaccines dose reduced mortality in hospitalized COVID-19 patients requiring oxygen supplementation: Evidence from the Beijing Omicron outbreak

“…This study has a significant advantage as most of the included patients experienced their first Omicron infection. By contrast, previous investigation 9 , 12 , 21 , 28 involved populations exposed to multiple waves of outbreaks, which could introduce biases in assessing vaccine efficacy due to previous viral infections and passive enhanced immune status.…”

“…Nonetheless, the case-control study design limited its level of evidence. Large-scale studies from Canada 21 and Iran 9 revealed an inverse dose-response relationship between vaccine dosage and in-hospital mortality but did not specifically examine the finding for inactivated vaccines. In contrast, a multi-center cohort investigation conducted in Spain and Argentina 12 has corroborated the efficacy of vaccines in mitigating in-hospital mortality among individuals afflicted with COVID-19 necessitating oxygen supplementation.…”

“…Evidence for the effectiveness of vaccines among hospitalized COVID-19 patients, who often exhibit distinct characteristics compared to individuals with mild or moderate disease, remains insufficient. Previous studies mostly focused on specific populations, including those in the intensive care unit (ICU), 3 , 9 pregnant and postpartum women, 10 and immunocompromised patients. 11 Only one study conducted in Spain 12 investigated the effectiveness of vaccines in patients who need oxygen support.…”