Safety and immunogenicity of a modified mRNA-lipid nanoparticle vaccine candidate against COVID-19: Results from a phase 1, dose-escalation study

📖 Top 20% JournalOct 18, 2024Human vaccines & immunotherapeutics

Safety and immune response of a new mRNA vaccine against COVID-19 in an early dose-testing study

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Abstract

In a study with 180 participants, 70.6% had prior SARS-CoV-2 infection.

Most participants experienced mild-to-moderate adverse events (AEs), with 98.1% reporting local and 96.7% systemic AEs.
Common AEs included injection site pain (57.5%) and myalgia (36.9%).
About 14.4% reported unsolicited AEs, mostly mild-to-moderate in severity.
Serious AEs occurred in 1.7% of participants, while 16.7% reported medically attended AEs, none linked to the vaccine.
Neutralizing antibody levels increased after the vaccine and then decreased over time, showing a dose-dependent response.
Results indicate potential for moving to a phase 2 trial.

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This phase 1, open-label, dose-escalation, multi-center study (NCT05477186) assessed the safety and immunogenicity of a booster dose of an mRNA COVID-19 vaccine (CV0501) encoding the SARS-CoV-2 Omicron BA.1 spike protein. Participants aged ≥ 18 years previously vaccinated with ≥ 2 doses of an mRNA COVID-19 vaccine received CV0501 doses ranging from 12 to 200 μg. After assessment of safety and immunogenicity of the 12 μg dose in 30 adults, 30 adults ≤ 64 years were randomized to receive either a 3 or 6 μg dose. Solicited adverse events (AEs) were collected for 7 days, unsolicited AEs for 28 days, and serious AEs (SAEs), medically attended AEs (MAAEs), and AEs of special interest (AESIs) until day (D) 181 post-vaccination. Serum neutralizing titers specific to SARS-CoV-2 BA.1, wild-type, Delta, and additional Omicron subvariants were assessed at D1, D15, D29, D91, and D181. Of 180 vaccinated participants (mean age: 49.3 years; 57.8% women), 70.6% had prior SARS-CoV-2 infection. Most solicited local (98.1%) and systemic (96.7%) AEs were of mild-to-moderate severity; the most common were injection site pain (57.5%; 33.3-73.3% across groups) and myalgia (36.9%; 13.3-56.7%). Unsolicited AEs were reported by 14.4% (6.7-26.7%) of participants (mild-to-moderate severity in 88.5% of the participants). Three participants (1.7%) reported SAEs, 16.7% (6.7-30.0%) reported MAAEs, and 8.3% (0.0-13.3%) reported AESIs (15 COVID-19 cases), none related to vaccination. Geometric means of serum neutralizing titers increased from baseline to D15 and D29 (dose-dependent), and then decreased over time. The safety and immunogenicity results supported advancement to a phase 2 trial.

Key numbers

4.4×

Increase in Neutralizing Antibody Response

Neutralizing geometric mean titers against SARS-CoV-2 variants at day 15 post-vaccination.

98.1%

Solicited Adverse Events

Percentage of participants reporting local adverse events after vaccination.

1.7%

Serious Adverse Events

Percentage of participants reporting serious adverse events during the study.

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