Moderna mNEXSPIKE: New COVID-19 Vaccine Approved in Europe – Dosage & Differences
On , the European Commission granted marketing authorization to mNEXSPIKE (mRNA-1283), a new COVID-19 vaccine developed by Moderna. This vaccine is authorized for individuals aged 12 years and older for active immunization against SARS-CoV-2, representing the third Moderna vaccine to receive approval within the European Union, joining SPIKEVAX, and mRESVIA.
Understanding mNEXSPIKE: A New Approach to COVID-19 Vaccination
mNEXSPIKE utilizes messenger RNA (mRNA) technology, similar to SPIKEVAX, but with a key difference in the genetic code it delivers. The active substance is a single-stranded mRNA molecule produced through a cell-free process, encoding only the N-terminal domain and the receptor-binding domain of the SARS-CoV-2 viral Spike (S) protein – specifically, the XBB.1.5 variant. This contrasts with SPIKEVAX, which encodes the entire Spike protein.
Key Differences Between SPIKEVAX and mNEXSPIKE
Several distinctions set mNEXSPIKE apart from its predecessor, SPIKEVAX. These differences span vaccine technology, dosage, indications, considerations for pregnant individuals, and demonstrated efficacy.
Vaccine Technology
As noted, the fundamental difference lies in the portion of the Spike protein targeted. SPIKEVAX instructs cells to produce the full-length Spike protein, while mNEXSPIKE focuses on the receptor-binding domain, the part of the virus that directly attaches to human cells. This targeted approach may elicit a more focused immune response.
Dosage
mNEXSPIKE is administered in a lower dose than SPIKEVAX. The vaccine is supplied in pre-filled syringes containing 10 micrograms (mcg) of mRNA in 0.2 mL. In comparison, SPIKEVAX syringes contain 25 mcg/0.25 mL for children aged 6 months to 11 years and 50 mcg/0.5 mL for individuals 12 years and older.
Indications
The authorized indications also differ. SPIKEVAX is approved for active immunization against COVID-19 in individuals aged 6 months and older, while mNEXSPIKE is currently authorized for those aged 12 years and older.
Use in Pregnancy
SPIKEVAX has been authorized for use during pregnancy, whereas, as a precautionary measure, the use of mNEXSPIKE is best avoided during pregnancy.
Efficacy
Clinical trials have indicated a potential advantage in efficacy with mNEXSPIKE. Data suggest a 9.3% higher relative vaccine effectiveness (RVE) compared to SPIKEVAX in individuals aged 12 years and older. A descriptive subgroup analysis further showed a 13.5% higher RVE in adults aged 65 years and older. Seroconversion rates and geometric mean neutralizing antibody titers were observed to be higher with mNEXSPIKE.
Storage and Handling
Storage requirements also vary between the two vaccines. SPIKEVAX single-dose vials can be stored for 9 months between -50°C and -15°C, 30 days between 2°C and 8°C (protected from light), and a maximum of 24 hours between 8°C and 25°C. MNEXSPIKE, can be stored for 1 year between -40ºC and -15ºC, 30 days between 2°C and 8°C (protected from light), and a maximum of 24 hours between 8°C and 25°C.
Global Approvals and Considerations
While authorized in Europe, the specific approvals for mNEXSPIKE differ slightly across countries. In the United States, the vaccine is approved for use in adults 65 years and older, and for individuals aged 12 to 64 years with underlying risk factors as defined by the Centers for Disease Control and Prevention. Canada has authorized mNEXSPIKE only for individuals 18 years and older who have already received prior COVID-19 vaccination. Australia, like Europe, has approved the mNEXSPIKE XBB.1.5 vaccine for administration to people aged 12 and older.
The authorization of mNEXSPIKE represents a continued effort to refine and adapt COVID-19 vaccines to address evolving viral variants and maintain protection against the disease. As COVID-19 transitions towards an endemic respiratory illness, vaccines like mNEXSPIKE will play a crucial role in mitigating severe outcomes, particularly among vulnerable populations.