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Study record
NCT05132855First Published: 2021 Nov 24Updated Date: 2022 Jun 23

Safety, Reactogenicity, and Immunogenicity of Heterologous Boost Third Dose of mRNA and Protein COVID-19 Vaccine: a Single-blind and Randomized Study

  1. Study Type
  2. Interventional
  1. Study Aim
  2. Prevention
  1. Study Design
  2. Parallel/Crossover
  1. Intervention Assignment
  2. Randomised
Reference record

Titers and capacity of neutralizing antibodies against SARS-CoV-2 variants after heterologous booster vaccination in health care workers primed with two doses of ChAdOx1 nCov-19: a single-blinded, randomized clinical trial

Chuang C-H, Huang C-G, Huang C-T, Chen Y-C, Kung Y-A, Chen C-J, Chuang T-C, Liu C-C, Huang P-W, Yang S-L, Gu P-W, Shih S-R, Chiu C-H
Journal article
Report Results
Background: Booster vaccination is important because of waning immunity and variant immune evasion. We conducted a single-blinded, randomized trial to evaluate the safety, reactogenicity, and immunogenicity of heterologous booster vaccination in health care workers (HCW) who had received two doses of ChAdOx1 nCov-19. Methods and findingsHCW at least 90 days after the second dose were enrolled to receive one of the four vaccines: BNT162b2, half-dose mRNA-1273, mRNA-1273, and MVC-COV1901. The primary outcomes were humoral and cellular immunogenicity and the secondary outcomes safety and reactogenicity 28 days post-booster. 340 HCW were enrolled: 83 received BNT162b2 (2 excluded), 85 half-dose mRNA-1273, 85 mRNA-1273, and 85 MVC-COV1901. mRNA vaccines had more reactogenicity than protein vaccine. Anti-spike IgG increased by a fold of 8.4 for MCV-COV1901, 32.2 for BNT162b2, 47.6 for half-dose mRNA-1273 and 63.2 for mRNA1273. The live virus microneutralization assay (LVMNA) against the wild type, alpha and delta variants were consistent with anti-spike IgG for all booster vaccines. The LVMNA in the four groups against omicron variant were 6.4 to 13.5 times lower than those against the wild type. Serum neutralizing antibody against omicron variant was undetectable in 60% of the participants who received MCV-COV1901 as a booster by LVMNA. By using pseudovirus neutralizing assay, we found that neutralization activity in the four groups against omicron variant were 4.6 to 5.2 times lower than that against the D614G. All booster vaccines induced comparable T cell response. Conclusions: Third dose booster not only increases neutralizing antibody titer but also enhances antibody capacity against SARS-CoV-2 variants. mRNA vaccines are preferred booster vaccines for those after primary series of ChAdOx1 nCov-19. Trial NCT05132855 [Preprints are preliminary reports of work that have not been peer reviewed. Refer to the original preprint or preprint server for specific information about the individual preprint.]
Copyright 2022 Elsevier B.V., All rights reserved
Reference record

The Immune Response of Heterologous Boost Third Dose of mRNA and Protein COVID-19 Vaccine: a Single-blind, and Randomized Study

Chang Gung Memorial Hospital
First Published (first received 2021 November 24) (
Trial registry record
No Results
The severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) specific antibody and neutralizing antibody level induced by adenovirus vector vaccines were lower than mRNA vaccines. Vaccine efficacy of ChAdOx1 nCoV-19 was lower than BNT162b2 and mRNA 1273 in clinical trials. The emergence of highly transmissible and mutant variants of SARS-COV-2 has raised the concern of COVID-19 vaccine effectiveness. The complete vaccination rate is still low in Taiwan. Strict border control measures are imposed by Central Epidemic Command Center. However, the measure of quarantine for flight crew is considered one of the breach of COVID-19 infection control. Despite most of the flight crew has fully vaccinated, several episodes of breakthrough infection occurred among flight crew resulting in domestic infection recently. Low neutralizing antibody was found in a proportion of fully vaccinated flight crew and healthcare workers. A 3rd booster COVID-19 dose is considered for flight crew and healthcare workers. This study is to determine the safety, reactogenicity, and immunogenicity of heterologous 3rd booster of mRNA and protein COVID-19 vaccines