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

Front Immunol. 2023 Sep 6:14:1244373. doi: 10.3389/fimmu.2023.1244373. eCollection 2023.

Abstract

Introduction: China experienced a record surge of coronavirus disease 2019 cases in December 2022, during the pandemic.

Methods: We 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.

Results: A 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.

Discussion: Compared 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.

Keywords: Ad5-nCoV; COVID-19; SARS-CoV-2; breakthrough infection; fourth dose.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Antibodies / immunology
  • Antibodies, Viral / immunology
  • Breakthrough Infections* / epidemiology
  • Breakthrough Infections* / immunology
  • Breakthrough Infections* / prevention & control
  • COVID-19 Vaccines* / immunology
  • COVID-19 Vaccines* / therapeutic use
  • COVID-19* / immunology
  • COVID-19* / prevention & control
  • China / epidemiology
  • Disease Outbreaks / statistics & numerical data
  • East Asian People
  • Humans
  • Immunization, Secondary
  • Pandemics / statistics & numerical data
  • Prospective Studies
  • SARS-CoV-2
  • Vaccine Efficacy
  • Vaccines, Inactivated / immunology
  • Vaccines, Inactivated / therapeutic use

Substances

  • Antibodies
  • COVID-19 Vaccines
  • Vaccines, Inactivated
  • Antibodies, Viral
  • Ad5-nCoV vaccine

Supplementary concepts

  • COVID-19 vaccine booster shot

Grants and funding

This work was supported by the Key Research and Development Program of Zhejiang Province (2021C03200), the Key Program of Health Commission of Zhejiang Province/Science Foundation of National Health Commission (WKJ-ZJ-2221), the Major Program of Zhejiang Municipal Natural Science Foundation (LD22H190001), the Explorer Program of Zhejiang Municipal Natural Science Foundation (LQ23H100001), the General Plan for Agricultural and Social Development Research Projects of Hangzhou(20201203B27), and the General Project of Hangzhou Health Science and Technology Plan (B20230116).