Journal Article

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

Wang, Chang-Shuang, Wu, Zhi-Yin, Tang, Lin, Wang, Hai-Feng, Ye, Ying, Huang, Chang, Pan, Jing-Jing, Wang, Fu-Zhen, Zhang, Yan-Yang, Qian, Zhao-Hui, Li, Ya-Fei, Ma, Ya-Ting, Rodewald, Lance Everett, Wang, Ai-Bin, Zheng, Hui, Wang, Xuan-Yi, Lu, Ming-Xia, Zhang, Rui, Lv, Xiao-Ya, An, Zhi-Jie, Yin, Zun-Dong, Wu, Dan, Shao, Yi-Ming

2022

Overview

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.

• Publisher: Taylor & Francis,Taylor & Francis Ltd,Taylor & Francis Group
• Subject: booster immunization / case-case study / Coronaviruses / COVID-19 vaccine / COVID-19 vaccines / Ct value / Immunization / Infections / Pneumonia / real-world study / Severe acute respiratory syndrome coronavirus 2