Frontiers in Immunology (Sep 2023)

Study of efficacy and antibody duration to fourth-dose booster of Ad5-nCoV or inactivated SARS-CoV-2 vaccine in Chinese adults: a prospective cohort study

  • Nani Xu,
  • Yu Xu,
  • Rongrong Dai,
  • Lin Zheng,
  • Pan Qin,
  • Peng Wan,
  • Yejing Yang,
  • Jianmin Jiang,
  • Jianmin Jiang,
  • Hangjie Zhang,
  • Hangjie Zhang,
  • Xiaowei Hu,
  • Huakun Lv,
  • Huakun Lv

DOI
https://doi.org/10.3389/fimmu.2023.1244373
Journal volume & issue
Vol. 14

Abstract

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IntroductionChina experienced a record surge of coronavirus disease 2019 cases in December 2022, during the pandemic.MethodsWe conducted a randomized, parallel-controlled prospective cohort study to evaluate efficacy and antibody duration after a fourth-dose booster with Ad5-nCoV or inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine.ResultsA total of 191 participants aged ≥18 years who had completed a three-dose regimen of the inactivated SARS-CoV-2 vaccine 6 months earlier were recruited to receive the intramuscular Ad5-nCoV booster or the inactivated SARS-CoV-2 vaccine. The Ad5-nCoV group had significantly higher antibody levels compared with the inactivated vaccine group at 6 months after the fourth vaccination dose. After the pandemic, the breakthrough infection rate for the Ad5-nCoV and the inactivated vaccine groups was 77.89% and 78.13%, respectively. Survival curve analysis (p = 0.872) and multivariable logistic regression analysis (p = 0.956) showed no statistically significant differences in breakthrough infection between the two groups.DiscussionCompared with a homologous fourth dose, a heterologous fourth dose of Ad5-nCoV elicited a higher immunogenic response in healthy adults who had been immunized with three doses of inactivated vaccine. Nevertheless, the efficacy of the two vaccine types was equivalent after the pandemic.

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