Safety and immunization of the SARS-CoV-2 mRNA-1273 vaccine in older adults

Test design and participants

We initially included participants between 18 and 55 years of age in a Phase I, dose-escalation, open-label clinical trial of mRNA-1273.2 In which we evaluated doses of 25 μg, 100 μg and 250 μg. We subsequently expanded the test to include 40 participants who were 56 years of age or older and who were stratified into two subgroups: those aged 56 years to 70 years and those aged 71 years or older. . While clinically significant systemic reactivity was observed in participants between 18 and 55 years old at the 250-μg dose, we administered doses of 25 μg or 100 μg to older participants.

The test was conducted at the Kaiser Permanente Washington Health Research Institute in Atlanta, Emory University School of Medicine in Atlanta and the National Institute of Allergy and Infectious Diseases (NIAID) Vaccine Research Center in Bethesda, Maryland. Controlled adults were healthy before undergoing any study procedures and provided written informed consent. We did not examine evidence of previous or current SARS-CoV-2 infection by testing blood or nasal samples prior to enrollment. The full eligibility criteria, along with a description of test design, conduct, inspection, and statistical analysis, are described in the protocol, available at with the full text of this article.

mRNA-1273 vaccine

The MRNA-1273 vaccine was coded by researchers at the NIAID Vaccine Research Center and Moderna, Cambridge, Massachusetts. This vaccine encodes a stable version of the SARS-CoV-2 full-length spike glycoprotein trimer, S-2P, which has been modified to include two proline substitutions on top of the central helix in the S2 subunit. MRNA is deposited in lipid nanoparticles at a volume of 0.5 mg per milliliter and diluted with normal saline to achieve the ultimate target vaccine concentrations.

Study status

NIAID acted as the test sponsor and made all decisions regarding the design and implementation of the study. The Vaccine Investigational New Drug Application and Protocol Amendments Expanding Age Subgroups were reviewed by the Food and Drug Administration and Institutional Review Board, Advara, a regulatory compliance consulting company that served as a single institutional review board for all study sites. did. An independent data and security monitoring committee reviewed the interim security reports.

Modern provided mRNA-1273 for use in this trial, but did not provide any financial support. Moderna’s staff collaborated in protocol development, contributed to the discovered new drug application, and participated in weekly team meetings regarding the study.

Emmes, the statistical and data coordination center for the study, developed a statistical analysis plan and performed all data analyzes. Data reports, which were generated from raw data by the Statistical and Data Coordination Center, were provided and available to all authors. The manuscript was written entirely by the authors, with the first two authors being the overall lead authors. All authors pledge for completeness and accuracy of the data and for adherence to the study of the protocol. Any person who is not an author contributed to the writing of the manuscript.

Trial process

The mRNA-1273 vaccine was given as 0.5 ml intramuscular injection on days 1 and 29 of the study; The same dose of vaccine was given on both days. Follow-up visits were determined 7 and 14 days after administration of each dose of vaccine and 57. A standard toxicity scale was used for adverse events (Table S1 in the Appendix Appendix available at NJJM dot ORG). Solid local and systemic adverse events were collected for 7 days after each vaccination, as facilitated by the use of memory assistance. Data regarding unwanted adverse events and use of new drugs were collected through day 57. Collection of samples, as well as adverse events for careful monitoring, development of new chronic medical conditions and serious adverse events were scheduled to continue through 1 year. After the last dose. These preliminary findings will be updated with the final safety and immunogenicity data when the results are available.

Preliminary safety data from the first phase of the study were available from participants between the ages of 18 and 55,2 Administration of mRNA-1273 was started sequentially in a subgroup of participants between the ages of 56 and 70 at a 25-μg dose, followed by a 100-μg dose. Since participants in this subgroup did not receive any pausing regimens after completion of 8 days, vaccine administration was initiated sequentially in a subgroup of participants who were 71 years of age or older who were 25-μg 100-μg dose after initiation.

Assessment of antibody response

We performed enzyme-linked immunosorbent assays (ELISA) 614 (containing the SP (D) residue in the early Wuhan-1 strain sequence) to determine IgG responses binding to S2P.8) And for receptor-binding domains at 1, 15, 29, 36, 43, and 57 days. (The receptor-binding domain is part of the SARS-CoV-2 virus that is located on its spike domain and that link with the body’s receptors to infect cells.) A SARS-CoV-2 native spike-pseudotiped lentavirus reporter Single-round-of-infection neutralization assays (pseudovirus virus neutralization assays) were used to assess vaccine-induced neutralizing activity against the 614D variant at the same time. time points. Vaccine-induced neutralization on day 43 was evaluated with the use of a 614-gly (614G) polymorphic variant with a second pseudovirus neutralization assay, as the 614G strain predominated both in the United States and worldwide.9 (Details are given in the methods section in the Supplementary Appendix.)

Three live-virus neutralization methods were used: first, the SARS-CoV-2 nanoluciferase high-throughput neutralization assay (nLuc HTNA), which uses viruses expressing the reporter gene nanoluciferase (nLuc)10; Second, the focus reduction neutralization test mNeonGreen (FRNT-mNG), which uses recombinant SARS-CoV-2 expressing the fluorescent reporter gene mNeonGreen1 1; And third, a SARS-CoV-2 plaque-reduction test (PRNT) assay, which uses wild-type viruses. We used nLuc HTNA to analyze participants who were 56, or older, and who received 100-μg doses on days 1, 29, and 43. We used the FRNT-mNG assay to analyze samples obtained on days 1, 29 and 43 from all participants in two-year-old age and dose subgroups. For this preliminary report, due to the time-intensive nature of the PRNT assay and maximizing useful information derived from its use, we used PRNT for the presence of SARS-CoV-2 on samples obtained from those participants on days 1 and 43. performed assays, which received only 100-μg doses. We used comparisons as previously reported results for participants between 18 and 55 years of age who were enrolled in the 100-μg subgroup, as well as results from controls who had convocation serum. Had donated2 The severity of Kovid-19 disease was noted for 38 of these controls and was classified as mild in 63% of participants, moderate in 22%, and severe in 15% (hospitalization, intensive care, ventilation or Defined as requiring both).

Assessment of T-cell responses

On days 1, 29 and 43 of intracellular cytokine-staining assays were performed to quantify antigen-specific T-cell responses against spike proteins. (Details are given in the Supplementary Appendix.)

Statistical analysis

Safety analysis included all participants who received at least one dose of mRNA-1273. Immunization results exclude samples that were obtained after 29 days in a participant who received only one dose of the vaccine. No other data points were missing. Seroconversion was defined as an increase in antibody titer as a factor of 4 or more from baseline. Geometric means were calculated by log transform data points and 95% confidence intervals on mean-transformed data. The log-transferred mean and 95% confidence intervals were then changed back to the original scale. We used Student’s t-test to calculate confidence intervals. Interim analysis was determined in the study subgroup to inform important decisions about vaccine development.

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