ChAdOx1 nCoV-19 vaccine for SARS-CoV-2

Abstract

The ChAdOx1 nCoV-19 vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), described by Pedro Folegatti and colleagues,1Folegatti PM Ewer KJ Aley PK et al.Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trial.Lancet. 2020; 396: 467-478Summary Full Text Full Text PDF PubMed Scopus (1428) Google Scholar was an important milestone in vaccine development to contain the ongoing pandemic. The vaccine is one of several SARS-CoV-2 vaccines that have entered the human trial phase, and the phase 1/2 trial showed encouraging results. This trial has focused on the most relevant clinical outcomes of safety, reactogenicity, and immunogenicity of the vaccine. The recruited participants (ie, healthy adults aged 18–55 years who were negative for SARS-CoV-2) were randomly assigned to receive either the vaccine (ie, ChAdOx1 nCoV-19 at a dose of 5 × 104 viral particles) or an active control (ie, a meningococcal conjugate vaccine; MenACWY) as a single intramuscular injection. The study showed the safety, reac­togenicity, and immunogenicity of the ChAdOx1 nCoV-19 vaccine. Although the outcomes were meticulously planned, an important outcome, anaphylactic reaction, was not mentioned. Anaphylaxis is important to consider while a new vaccine is being tested.2McNeil MM DeStefano F Vaccine-associated hypersensitivity.J Allergy Clin Immunol. 2018; 141: 463-472Summary Full Text Full Text PDF PubMed Scopus (146) Google Scholar Additionally, the selection criteria for ten participants in group 3, who were recruited in a non-randomised way, needs to be described. The trial is labelled as a randomised controlled trial and the criteria for recruiting participants in a non-randomised method should be made available. While we looked at the immunogenicity outcomes in figure 3,1Folegatti PM Ewer KJ Aley PK et al.Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trial.Lancet. 2020; 396: 467-478Summary Full Text Full Text PDF PubMed Scopus (1428) Google Scholar we noted that the number of participants who were analysed was different at each follow-up stage. Some explanation for this difference needs to be given to make the findings more applicable. In the trial, participants with high titres of neutralising antibodies at baseline were also included in the same analysis, but whether the rise in their antibody titres affected the overall results and whether the non-randomised recruitment of the participants influenced the comparison is unclear. In the group of participants receiving ChAdOx1 nCoV-19 and paracetamol, the adverse event of itching was higher than in participants receiving ChAdOx1 nCoV-19 without paracetamol, which needs to be investigated. Although phase 2 trials are usually underpowered for reporting of efficacy outcomes,3Tomblyn MR Rizzo JD Are there circumstances in which phase 2 study results should be practice-changing?.Hematology Am Soc Hematol Educ Program. 2007; 2007: 489-492Crossref Scopus (14) Google Scholar Folegatti and colleagues have planned to assess them. We hope to read about the results of the vaccine trial soon. We declare no competing interests. ChAdOx1 nCoV-19 vaccine for SARS-CoV-2 – Authors' replyWe agree with Anil Chauhan and colleagues that recording of anaphylaxis is important when testing a new vaccine. All participants in the trial were observed in the clinic for at least 30 min after they were vaccinated, and no cases of anaphylaxis occurred.1 Full-Text PDF Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trialChAdOx1 nCoV-19 showed an acceptable safety profile, and homologous boosting increased antibody responses. These results, together with the induction of both humoral and cellular immune responses, support large-scale evaluation of this candidate vaccine in an ongoing phase 3 programme. Full-Text PDF Open AccessChAdOx1 nCoV-19 vaccine for SARS-CoV-2As a participant in the ChAdOx1 nCoV-19 vaccine trial, I was particularly excited to read the preliminary report by Pedro Folegatti and colleagues1 and congratulate the team on their promising results. Full-Text PDF