Vaccine Info

Moderna COVID-19 Vaccine (SpikeVax)

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Last reviewed
September 14, 2023

Moderna COVID-19 Vaccine (SpikeVax® XBB.1.5)

Moderna Inc.'s SpikeVax® COVID-19 Vaccine is a Messenger RNA (mRNA) vaccine targeted against the SARS-CoV-2 betacoronavirus to prevent severe COVID-19. SpikeVax encodes for a prefusion stabilized form of the Spike (S) protein selected by Moderna Inc. in collaboration with U.S. NIAID Vaccine Research Center investigators. SpikeVax's active ingredient is CX-024414 (single-stranded, 5’-capped mRNA), produced using a cell-free in vitro transcription from the corresponding DNA templates, encoding the S protein of the SARS-CoV-2 virus.

Moderna Inc. designs its mRNA vaccines using the virus's sequence but not the virus itself. mRNA is a single-stranded molecule that carries genetic code from DNA in a cell's nucleus to ribosomes, the cell's protein-making machinery. The mRNA instructs a patient's cells to produce proteins that prevent, treat, or cure disease. Moderna says mRNA plays a fundamental role in human biology, transferring the instructions stored in DNA to make the proteins required in every living cell.

On December 18, 2020, the U.S. Food and Drug Administration (FDA) issued an emergency use authorization (EUA). SpikeVax (elasomeran mRNA vaccine) Accession Number: DB15654; Preferred Substance Name: CX-024414; UNII: EPK39PL4R4;  MedlinePlus a621002. On January 24, 2023, the FDA published a Briefing Document, Future Vaccination Regimens Addressing COVID-19. During the FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) digital meeting on January 26, 2023, Moderna's Antonella Lozito, PharmD Executive Director, presented COVID-19 Bivalent Vaccines Primary Series and Booster. The FDA published a Briefing Document on June 15, 2023.

On September 6, 2023, Moderna announced its updated COVID-19 vaccine mRNA-1273.815, which generated an 8.7-fold increase in neutralizing antibodies in humans against the BA.2.86 (Pirola) variant. On September 11, 2023, the FDA approved the supplemental Biologics License Application(sBLA) for Spikevax® for ages 12 years and above. An EUA for the Moderna COVID-19 Vaccine was also received for individuals six months through 11 years of age. Health Canada and the European Medicines Agency (EMA) have authorized the Spikevax XBB.1.5 COVID-19 vaccine for people six months of age and older in September 2023. 

The U.S. Centers for Disease Control (CDC) indicates that the highly mutated BA.2.86 variant may be more capable of causing infection in people who previously had COVID-19 or were vaccinated with previous vaccines, noting that updated COVID-19 vaccines may be effective in reducing severe disease and hospitalization.

Moderna, Inc. is advancing messenger RNA science to create a new transformative medicine class for patients. mRNA medicines are designed to direct the body's cells to produce intracellular, membrane, or secreted proteins that can have a therapeutic or preventive benefit and potentially address a broad spectrum of diseases—headquartered in Cambridge, MA. Moderna Inc.'s 10-Q SEC filing on January 4, 2021, indicates 'mRNA is considered a gene therapy product by the U.S. FDA' (pINN elasomeran). To learn more, visit

SpikeVax XBB.1.5 Vaccine Dosage

Moderna's COVID-19 vaccines are offered in various doses, subject to country-based authorizations. In April 2023, participants received mRNA-1273.815 (n=50) and mRNA-1273.231 (n=51). The median intervals from the prior BA.4/BA.5-containing bivalent vaccine doses were 8.2 and 8.3 months for the mRNA-1273.815 and mRNA-1273.231 groups, respectively. Both vaccines increased neutralizing antibody geometric mean titers against all variants tested at day 15 post-booster nAb compared to pre-booster levels. Geometric mean fold-rises from pre-booster titers after the monovalent booster were numerically higher against XBB.1.5, XBB.1.16, and SARS-CoV-2 (D614G) than those of the bivalent booster. They were comparable against BA.4/BA.5 and BQ1.1 variants for both vaccines. The monovalent vaccine also elicited nAb responses against omicron XBB.2.3.2, EG.5.1, FL.1.5.1, and BA.2.86, similar to those against XBB.1.5 in a subset (n=20) of participants. 

SpikeVax Vaccine History

The first clinical batch of the Moderna vaccine candidate (CX-024414), funded by the Coalition for Epidemic Preparedness Innovations, was completed on February 7, 2020.

COVID-19 Vaccine (Moderna) Clinical Trials 

Moderna continues to run clinical trials to evaluate the safety, immunogenicity, and reactogenicity of its COVID-19 vaccine.

Clinical Trials

No clinical trials found