What You Need to Know
The FDA has approved Moderna's new COVID-19 vaccine, mRNA-1283 (mNEXSPIKE), for adults 65 and older and individuals 12–64 with at least one CDC-defined underlying risk factor.
In a phase 3 trial with over 11,000 participants, mRNA-1283 demonstrated 9.3% higher relative efficacy than Moderna’s original vaccine (mRNA-1273), with a 13.5% higher efficacy in adults 65+.
The vaccine also showed fewer local side effects and a safety profile comparable to its predecessor.
Participants received either a 10 μg dose of mRNA-1283 or a 50 μg dose of mRNA-1273. mRNA-1283 showed a 9.3% higher relative vaccine efficacy (rVE) compared to mRNA-1273 in individuals aged 12 years and older, and in a descriptive sub-group analysis, a 13.5% higher rVE in adults aged 65 and older.
In this trial, mRNA-1283 was found to have a similar safety profile to mRNA-1273, with fewer local reactions and comparable systemic reactions. The most commonly solicited side effects were injection site pain, fatigue, headache and myalgia.
Moderna said it expects to have the mRNA-1283 vaccine ready in the US for the 2025-2026 respiratory virus season. Additionally, the vaccine is under review with regulators in multiple markets around the world.
New Federal COVID-19 Vaccine Guidelines
Earlier this week, the leaders of the NIH, HHS, and FDA, announced the removal of the COVID-19 vaccine from the immunization schedule for pregnant women and healthy children in a social media post.
However, since that post, the federal government has yet again changed its stance on the vaccine and healthy children. In fact on the CDC's Child and Adolescent Immunization Schedule by Age, the COVID-19 vaccines will be available to the pediatric population under what is Shared clinical decision-making in the guidance. This addresses children ages 6 months –17 years who are not moderately or severely immunocompromised, and it says the following: "Shared clinical decision-making vaccinations are individually based and informed by a decision process between the health care provider and the patient or parent/guardian. Where the parent presents with a desire for their child to be vaccinated, children 6 months and older may receive COVID-19 vaccination, informed by the clinical judgment of a healthcare provider and personal preference and circumstances," the CDC says on the website.
References
1. Moderna Receives U.S. FDA Approval for COVID-19 Vaccine mNEXSPIKE. Moderna press release. May 31, 2025. Accessed May 31, 2025.
https://investors.modernatx.com/news/news-details/2025/Moderna-Receives-U-S--FDA-Approval-for-COVID-19-Vaccine-mNEXSPIKE/default.aspx
2.Prasad V, Makary MA. An Evidence-Based Approach to Covid-19 Vaccination. N Engl J Med. Published online May 20, 2025. doi:10.1056/NEJMsb2506929