tetano
Editor, Senior Moderator
Vaccines (Basel)
. 2022 Oct 19;10(10):1753.
doi: 10.3390/vaccines10101753.
Effectiveness of Inactivated COVID-19 Vaccines against COVID-19 Caused by the SARS-CoV-2 Delta and Omicron Variants: A Retrospective Cohort Study
Qiaoli Hua[SUP] 1 [/SUP], Danwen Zheng[SUP] 2 3 [/SUP], Bo Yu[SUP] 4 [/SUP], Xinghua Tan[SUP] 5 [/SUP], Qiumin Chen[SUP] 6 [/SUP], Longde Wang[SUP] 7 [/SUP], Jing Zhang[SUP] 8 [/SUP], Yuntao Liu[SUP] 2 3 [/SUP], Heng Weng[SUP] 9 10 [/SUP], Yihang Cai[SUP] 1 [/SUP], Xiaohua Xu[SUP] 2 3 [/SUP], Bing Feng[SUP] 11 [/SUP], Guangjuan Zheng[SUP] 11 [/SUP], Banghan Ding[SUP] 2 3 [/SUP], Jianwen Guo[SUP] 3 9 10 [/SUP], Zhongde Zhang[SUP] 2 3 9 [/SUP]
Affiliations
Abstract
Background: Real-world evidence on the effectiveness of inactivated vaccines against the Delta and Omicron (BA.2.38) variants remains scarce.
Methods: A retrospective cohort study was conducted to estimate the adjusted vaccine effectiveness (aVE) of one, two, and three doses of inactivated vaccines in attenuating pneumonia, severe COVID-19, and the duration of viral shedding in Delta and Omicron cases using modified Poisson and linear regression as appropriate.
Results: A total of 561 COVID-19 cases were included (59.2% Delta and 40.8% Omicron). In total, 56.4% (184) of Delta and 12.0% (27) of Omicron cases had COVID-19 pneumonia. In the two-dose vaccinated population, 1.4% of Delta and 89.1% of Omicron cases were vaccinated for more than 6 months. In Delta cases, the two-dose aVE was 52% (95% confidence interval, 39-63%) against pneumonia and 61% (15%, 82%) against severe disease. Two-dose vaccination reduced the duration of viral shedding in Delta cases, but not in booster-vaccinated Omicron cases. In Omicron cases, three-dose aVE was 68% (18%, 88%) effective against pneumonia, while two-dose vaccination was insufficient for Omicron. E-values were calculated, and the E-values confirmed the robustness of our findings.
Conclusions: In Delta cases, two-dose vaccination within 6 months reduced pneumonia, disease severity, and the duration of viral shedding. Booster vaccination provided a high level of protection against pneumonia with Omicron and should be prioritized.
Keywords: a retrospective cohort study; coronavirus disease 2019; inactivated COVID-19 vaccine; the Delta variant; the Omicron (BA.2.38) variant.
. 2022 Oct 19;10(10):1753.
doi: 10.3390/vaccines10101753.
Effectiveness of Inactivated COVID-19 Vaccines against COVID-19 Caused by the SARS-CoV-2 Delta and Omicron Variants: A Retrospective Cohort Study
Qiaoli Hua[SUP] 1 [/SUP], Danwen Zheng[SUP] 2 3 [/SUP], Bo Yu[SUP] 4 [/SUP], Xinghua Tan[SUP] 5 [/SUP], Qiumin Chen[SUP] 6 [/SUP], Longde Wang[SUP] 7 [/SUP], Jing Zhang[SUP] 8 [/SUP], Yuntao Liu[SUP] 2 3 [/SUP], Heng Weng[SUP] 9 10 [/SUP], Yihang Cai[SUP] 1 [/SUP], Xiaohua Xu[SUP] 2 3 [/SUP], Bing Feng[SUP] 11 [/SUP], Guangjuan Zheng[SUP] 11 [/SUP], Banghan Ding[SUP] 2 3 [/SUP], Jianwen Guo[SUP] 3 9 10 [/SUP], Zhongde Zhang[SUP] 2 3 9 [/SUP]
Affiliations
- PMID: 36298618
- DOI: 10.3390/vaccines10101753
Abstract
Background: Real-world evidence on the effectiveness of inactivated vaccines against the Delta and Omicron (BA.2.38) variants remains scarce.
Methods: A retrospective cohort study was conducted to estimate the adjusted vaccine effectiveness (aVE) of one, two, and three doses of inactivated vaccines in attenuating pneumonia, severe COVID-19, and the duration of viral shedding in Delta and Omicron cases using modified Poisson and linear regression as appropriate.
Results: A total of 561 COVID-19 cases were included (59.2% Delta and 40.8% Omicron). In total, 56.4% (184) of Delta and 12.0% (27) of Omicron cases had COVID-19 pneumonia. In the two-dose vaccinated population, 1.4% of Delta and 89.1% of Omicron cases were vaccinated for more than 6 months. In Delta cases, the two-dose aVE was 52% (95% confidence interval, 39-63%) against pneumonia and 61% (15%, 82%) against severe disease. Two-dose vaccination reduced the duration of viral shedding in Delta cases, but not in booster-vaccinated Omicron cases. In Omicron cases, three-dose aVE was 68% (18%, 88%) effective against pneumonia, while two-dose vaccination was insufficient for Omicron. E-values were calculated, and the E-values confirmed the robustness of our findings.
Conclusions: In Delta cases, two-dose vaccination within 6 months reduced pneumonia, disease severity, and the duration of viral shedding. Booster vaccination provided a high level of protection against pneumonia with Omicron and should be prioritized.
Keywords: a retrospective cohort study; coronavirus disease 2019; inactivated COVID-19 vaccine; the Delta variant; the Omicron (BA.2.38) variant.