A case–case study on the effect of primary and booster immunization with China-produced COVID-19 vaccines on prevention of pneumonia and viral load among vaccinated persons infected by Delta and Omicron variants. Issue 1 (31st December 2022)

• Record Type: Journal Article
• Authors: Wu, Dan; Ye, Ying; Tang, Lin; Wang, Ai-Bin; Zhang, Rui; Qian, Zhao-Hui; Wang, Fu-Zhen; Zheng, Hui; Huang, Chang; Lv, Xiao-Ya; Wang, Hai-Feng; Zhang, Yan-Yang; Pan, Jing-Jing; Li, Ya-Fei; Lu, Ming-Xia; Wang, Chang-Shuang; Ma, Ya-Ting; An, Zhi-Jie; Rodewald, Lance Everett; Yin, Zun-Dong; Wang, Xuan-Yi; Wu, Zhi-Yin; Shao, Yi-Ming
• Is Part Of: Emerging microbes & infections. Volume 11:Issue 1(2022)
• Page Start: 1950
• Page End: 1958
• Publication Date: 2022-12-31
• Subjects: COVID-19 vaccine -- Ct value -- case-case study -- real-world study -- booster immunization; Medical microbiology -- Periodicals; Communicable diseases -- Periodicals; Infection -- Periodicals; 616.9041
• DOI: 10.1080/22221751.2022.2103455
• Languages: English
• ISSNs: 2222-1751

Abstract

ABSTRACT: Using a three-prefecture, two-variant COVID-19 outbreak in Henan province in January 2022, we evaluated the associations of primary and booster immunization with China-produced COVID-19 vaccines and COVID-19 pneumonia and SARS-CoV-2 viral load among persons infected by Delta or Omicron variant. We obtained demographic, clinical, vaccination, and multiple Ct values of infections ≥3 years of age. Vaccination status was either primary series ≥180 days prior to infection; primary series <180 days prior to infection, or booster dose recipient. We used logistic regression to determine odds ratios (OR) of Delta and Omicron COVID-19 pneumonia by vaccination status. We analysed minimum Ct values by vaccination status, age, and variant. Of 826 eligible cases, 405 were Delta and 421 were Omicron cases; 48.9% of Delta and 19.0% of Omicron cases had COVID-19 pneumonia. Compared with full primary vaccination ≥180 days before infection, the aOR of pneumonia was 0.48 among those completing primary vaccination <180 days and 0.18 among booster recipients among these Delta infections. Among Omicron infections, the corresponding aOR was 0.34 among those completing primary vaccination <180 days. There were too few (ten) Omicron cases among booster dose recipients to calculate a reliable OR. There were no differences in minimum Ct values by vaccination status among the 356 Delta cases or 70 Omicron cases. COVID-19 pneumonia was less common among Omicron cases than Delta cases. Full primary vaccination reduced pneumonia effectively for 6 months; boosting six months after primary vaccination resulted in further reduction. We recommend accelerating the pace of booster dose administration.