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An Improved and High Throughput Respiratory Syncytial Virus RSV Micro-neutralization Assay
Published on: January 26, 2019
Safety and immunogenicity of an mRNA-based RSV vaccine in seropositive children aged 12-59 months
Sabine Schnyder Ghamloush1, Sue Fanning2, Brandon Essink3
1Moderna, Inc., Cambridge, MA, USA.
Insights
mRNA-1345, a novel respiratory syncytial virus (RSV) vaccine, demonstrated strong safety and immunogenicity in children aged 12-59 months. The vaccine effectively boosted antibody levels against RSV without significant adverse events.
Area of Science:
- Pediatric infectious diseases
- Vaccinology
- Molecular virology
Background:
- Respiratory syncytial virus (RSV) is a leading cause of respiratory illness in young children.
- Existing RSV prevention strategies have limitations.
- mRNA vaccine technology shows promise for pediatric infectious disease prevention.
Purpose of the Study:
- To evaluate the safety and immunogenicity of mRNA-1345, an RSV prefusion F glycoprotein vaccine, in children aged 12-59 months.
- To assess the impact of different mRNA-1345 doses on antibody responses.
- To monitor adverse events and long-term safety outcomes.
Main Methods:
- Phase 1, randomized, observer-blind study (NCT04528719) involving RSV-seropositive children.
- Participants received three doses of mRNA-1345 (15 μg or 30 μg) or placebo.
- Safety and immunogenicity were assessed over a 12-month follow-up period.
Main Results:
- mRNA-1345 was well tolerated at both dose levels, with mild, transient local and systemic reactions.
- No serious adverse events, deaths, or study discontinuations due to adverse events were reported.
- A single dose significantly increased neutralizing antibody titers and binding antibody concentrations against RSV-A and RSV-B, with preF-biased responses.
Conclusions:
- mRNA-1345 is a safe and immunogenic candidate vaccine for preventing RSV in children.
- The vaccine effectively elicits robust antibody responses.
- Further investigation in larger trials is warranted to confirm efficacy.
Abstract:
Respiratory syncytial virus (RSV) is a common respiratory pathogen in children. After demonstrating safety and immunogenicity in adults, mRNA-1345 encoding the RSV prefusion (preF) stabilized F glycoprotein was investigated in children. This phase 1, randomized, observer-blind study assessed the safety and immunogenicity of mRNA-1345 (NCT04528719) in RSV-seropositive children (per microneutralization assay) aged 12-59 months and is part of a larger study in multiple populations. Participants received three doses of mRNA-1345 (15 μg or 30 μg) or placebo 56 days apart, with 12-month safety follow-up. Forty-six participants were randomized to receive mRNA-1345 15 μg (n = 15), mRNA-1345 30 μg (n = 16), or placebo (n = 15). mRNA-1345 was well tolerated at both dose levels. The most frequently reported solicited local adverse reaction (AR) was injection site tenderness (15 μg, 27.3%-50.0%; 30 μg, 53.3%-71.4%; placebo, 26.7%-33.3%). Most solicited systemic ARs were grade 1/2, with irritability/crying, loss of appetite, and sleepiness most frequently reported; reactogenicity did not increase with additional doses. Throughout the 12-month follow-up, no serious adverse events (AEs), deaths, AEs of special interest, or AEs leading to study discontinuation were reported. Three medically attended RSV infections were reported among placebo recipients. A single injection increased RSV-A and RSV-B neutralizing antibody titers (geometric mean fold rise [GMFR] over baseline: 15 μg, RSV-A = 18.9, RSV-B = 7.2; 30 μg, RSV-A = 34.9, RSV-B = 14.3) and RSV preF and postF binding antibody concentrations (GMFR: 15 μg, preF = 13.9, postF = 9.3; 30 μg, preF = 26.5, postF = 16.0); binding antibody responses were preF-biased. Subsequent doses did not further increase antibody levels. In conclusion, mRNA-1345 was well tolerated and boosted antibody levels in seropositive children aged 12-59 months.
