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Analysis of Factors Influencing the Clinical Severity of Omicron and Delta Variants

The Omicron variant is the dominant strain circulating globally, and studies have shown that Omicron cases have milder symptoms than Delta cases. This study aimed to analyze the factors that affect the clinical severity of Omicron and Delta variants, evaluate and compare the effectiveness of COVID-1...

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Autores principales: Zhao, Shanlu, Luo, Kaiwei, Guo, Yichao, Fang, Mingli, Sun, Qianlai, Dai, Zhihui, Yang, Hao, Zhan, Zhifei, Hu, Shixiong, Chen, Tianmu, Li, Xiaojun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10301725/
https://www.ncbi.nlm.nih.gov/pubmed/37368748
http://dx.doi.org/10.3390/tropicalmed8060330
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author Zhao, Shanlu
Luo, Kaiwei
Guo, Yichao
Fang, Mingli
Sun, Qianlai
Dai, Zhihui
Yang, Hao
Zhan, Zhifei
Hu, Shixiong
Chen, Tianmu
Li, Xiaojun
author_facet Zhao, Shanlu
Luo, Kaiwei
Guo, Yichao
Fang, Mingli
Sun, Qianlai
Dai, Zhihui
Yang, Hao
Zhan, Zhifei
Hu, Shixiong
Chen, Tianmu
Li, Xiaojun
author_sort Zhao, Shanlu
collection PubMed
description The Omicron variant is the dominant strain circulating globally, and studies have shown that Omicron cases have milder symptoms than Delta cases. This study aimed to analyze the factors that affect the clinical severity of Omicron and Delta variants, evaluate and compare the effectiveness of COVID-19 vaccines with different technological platforms, and assess the vaccine effectiveness against different variants. We retrospectively collected the basic information of all local COVID-19 cases reported by Hunan Province to the National Notifiable Infectious Disease Reporting System from January 2021 to February 2023, including gender, age, clinical severity, and COVID-19 vaccination history. From 1 January 2021 to 28 February 2023, Hunan Province reported a total of 60,668 local COVID-19 cases, of which, 134 were infected with the Delta variant and 60,534 were infected with the Omicron variant. The results showed that infection with the Omicron variant (adjusted OR (aOR): 0.21, 95% CI: 0.14–0.31), getting vaccinated (booster immunization vs. unvaccinated aOR: 0.30, 95% CI: 0.23–0.39) and being female (aOR: 0.82, 95% CI: 0.79–0.85) were protective factors for pneumonia, while old age (≥60 years vs. <3 years aOR: 4.58, 95% CI: 3.36–6.22) was a risk factor for pneumonia. Being vaccinated (booster immunization vs. unvaccinated aOR: 0.11, 95% CI: 0.09–0.15) and female (aOR: 0.54, 95% CI: 0.50–0.59) were protective factors for severe cases, while older age (≥60 years vs. < 3 years aOR: 4.95, 95% CI: 1.83–13.39) was a risk factor for severe cases. The three types of vaccines had protective effects on both pneumonia and severe cases, and the protective effect on severe cases was better than that on pneumonia. The recombinant subunit vaccine booster immunization had the best protective effect on pneumonia and severe cases, with ORs of 0.29 (95% CI: 0.2–0.44) and 0.06 (95% CI: 0.02–0.17), respectively. The risk of pneumonia from Omicron variant infection was lower than that from Delta. Chinese-produced vaccines had protective effects on both pneumonia and severe cases, with recombinant subunit vaccines having the best protective effect on pneumonia and severe pneumonia cases. Booster immunization should be advocated in COVID-19 pandemic-related control and prevention policies, especially for the elderly, and booster immunization should be accelerated.
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spelling pubmed-103017252023-06-29 Analysis of Factors Influencing the Clinical Severity of Omicron and Delta Variants Zhao, Shanlu Luo, Kaiwei Guo, Yichao Fang, Mingli Sun, Qianlai Dai, Zhihui Yang, Hao Zhan, Zhifei Hu, Shixiong Chen, Tianmu Li, Xiaojun Trop Med Infect Dis Article The Omicron variant is the dominant strain circulating globally, and studies have shown that Omicron cases have milder symptoms than Delta cases. This study aimed to analyze the factors that affect the clinical severity of Omicron and Delta variants, evaluate and compare the effectiveness of COVID-19 vaccines with different technological platforms, and assess the vaccine effectiveness against different variants. We retrospectively collected the basic information of all local COVID-19 cases reported by Hunan Province to the National Notifiable Infectious Disease Reporting System from January 2021 to February 2023, including gender, age, clinical severity, and COVID-19 vaccination history. From 1 January 2021 to 28 February 2023, Hunan Province reported a total of 60,668 local COVID-19 cases, of which, 134 were infected with the Delta variant and 60,534 were infected with the Omicron variant. The results showed that infection with the Omicron variant (adjusted OR (aOR): 0.21, 95% CI: 0.14–0.31), getting vaccinated (booster immunization vs. unvaccinated aOR: 0.30, 95% CI: 0.23–0.39) and being female (aOR: 0.82, 95% CI: 0.79–0.85) were protective factors for pneumonia, while old age (≥60 years vs. <3 years aOR: 4.58, 95% CI: 3.36–6.22) was a risk factor for pneumonia. Being vaccinated (booster immunization vs. unvaccinated aOR: 0.11, 95% CI: 0.09–0.15) and female (aOR: 0.54, 95% CI: 0.50–0.59) were protective factors for severe cases, while older age (≥60 years vs. < 3 years aOR: 4.95, 95% CI: 1.83–13.39) was a risk factor for severe cases. The three types of vaccines had protective effects on both pneumonia and severe cases, and the protective effect on severe cases was better than that on pneumonia. The recombinant subunit vaccine booster immunization had the best protective effect on pneumonia and severe cases, with ORs of 0.29 (95% CI: 0.2–0.44) and 0.06 (95% CI: 0.02–0.17), respectively. The risk of pneumonia from Omicron variant infection was lower than that from Delta. Chinese-produced vaccines had protective effects on both pneumonia and severe cases, with recombinant subunit vaccines having the best protective effect on pneumonia and severe pneumonia cases. Booster immunization should be advocated in COVID-19 pandemic-related control and prevention policies, especially for the elderly, and booster immunization should be accelerated. MDPI 2023-06-20 /pmc/articles/PMC10301725/ /pubmed/37368748 http://dx.doi.org/10.3390/tropicalmed8060330 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Zhao, Shanlu
Luo, Kaiwei
Guo, Yichao
Fang, Mingli
Sun, Qianlai
Dai, Zhihui
Yang, Hao
Zhan, Zhifei
Hu, Shixiong
Chen, Tianmu
Li, Xiaojun
Analysis of Factors Influencing the Clinical Severity of Omicron and Delta Variants
title Analysis of Factors Influencing the Clinical Severity of Omicron and Delta Variants
title_full Analysis of Factors Influencing the Clinical Severity of Omicron and Delta Variants
title_fullStr Analysis of Factors Influencing the Clinical Severity of Omicron and Delta Variants
title_full_unstemmed Analysis of Factors Influencing the Clinical Severity of Omicron and Delta Variants
title_short Analysis of Factors Influencing the Clinical Severity of Omicron and Delta Variants
title_sort analysis of factors influencing the clinical severity of omicron and delta variants
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10301725/
https://www.ncbi.nlm.nih.gov/pubmed/37368748
http://dx.doi.org/10.3390/tropicalmed8060330
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