Under section 564 of the Federal Food, Drug, and Cosmetic Act (FD&C Act), the FDA Commissioner may allow unapproved medical products or unapproved uses of approved medical products to be used in an emergency to diagnose, treat, or prevent serious or life-threatening diseases or conditions caused by chemical, biological, radiological or nuclear threat agents when there are no adequate, approved, and available alternatives. Vaccines that receive an EUA may later be fully licensed by the FDA.
All available COVID-19 vaccines were initially administered under EUA. All available 2025–2026 Formula COVID-19 vaccines are fully licensed by FDA and no longer administered under EUA.
Last reviewed:
November 16, 2025
Both the Pfizer-BioNTech COVID-19 Vaccine (Comirnaty) and the Moderna COVID-19 vaccines (Spikevax, mNexspike) are lipid nanoparticle-formulated, nucleoside-modified mRNA vaccines encoding the prefusion spike glycoprotein of SARS-CoV-2, the virus that causes COVID-19. The 2025–2026 formula mRNA vaccines target the Omicron JN.1 variant LP.8.1 strain. Moderna’s mNexspike was first licensed in 2025 for ages 12 years and older. It is designed to reduce the amount of mRNA required to elicit the same or slightly better immune response compared to Spikevax (10 mcg of mRNA versus 50 mcg of mRNA for an adult dose). Spikevax and mNexspike may be used interchangeably when both are age appropriate. Visit this CDC website for more details about how mRNA vaccines work: www.cdc.gov/covid/vaccines/how-they-work.html.
Last reviewed:
November 16, 2025
Spikevax and mNexspike are both mRNA vaccines targeting the same strain of COVID-19. Spikevax is the original vaccine now licensed down to age 6 months. The mNexspike product is a newer mRNA vaccine licensed for ages 12 years and older with an advanced design that achieves the same or slightly better immune response with less mRNA in each dose (10 mcg in mNexspike compared to 50 mcg in adult doses of Spikevax). The two products may be used interchangeably when age appropriate.
In adults 65 years and older (and moderately or severely immunocompromised adults) who are recommended to receive a second dose 6 months after their first 2025–2026 formula dose, the minimum interval between the two recommended 2025–2026 season doses is 3 months for mNexspike, but only 2 months for the other COVID-19 vaccine products. If mNexspike is inadvertently administered after only 2 months, the dose counts as valid and does not need to be repeated.
Last reviewed:
November 16, 2025
The original COVID-19 vaccines all targeted the spike protein of the original SARS-CoV-2 virus. The 2025–2026 formulation vaccines target the spike proteins of more recently circulating strains, known as the Omicron JN.1 lineage LP.8.1 strain (mRNA vaccines) or the JN.1 strain (Nuvaxovid adjuvanted protein subunit vaccine). The update is intended to boost production of antibodies that protect more effectively against disease caused by currently circulating Omicron subvariants.
The process of updating the strain without changing anything else is similar to the seasonal strain changes made for influenza vaccinations each year. Vaccine safety, side effects, and risk of allergic reactions are expected to be comparable to earlier formulations of vaccines of the same brand and dose. As with seasonal influenza vaccines, future COVID-19 vaccines can continue to be updated when needed, as the circulating viruses evolve.
Last reviewed:
November 16, 2025
No. The last U.S. doses of Janssen COVID-19 Vaccine expired May 7, 2023.
Last reviewed:
November 16, 2025
Nuvaxovid is the brand name of the adjuvanted protein subunit COVID-19 vaccine developed by Novavax and commercialized by Sanofi beginning in the 2025–26 season. It contains the Omicron JN.1 subvariant SARS-CoV-2 spike protein and Matrix-M adjuvant. The saponin-based adjuvant is made from extracts of the bark of the Soapbark tree native to Chile. It is added to enhance the immune response of the vaccine recipient. The spike protein is produced in insect cells.
The 2025–2026 formulation of Nuvaxovid is FDA-licensed for use in people age 12 years or older. It is recommended as a single dose for people age 12 years through 64 years, given at least 8 weeks after the most recent dose of COVID-19 vaccine, regardless of the recipient’s vaccination history. People age 65 years or older and those age 12 years and older who are moderately or severely immunocompromised are recommended to receive 2 doses of 2025–2026 Formula COVID-19 vaccines, 6 months apart (with a minimum interval of 2 months between doses if using Nuvaxovid for both doses).
A 2-dose initial series is recommended for previously unvaccinated recipients who are moderately or severely immunocompromised, with the doses given at least 3 weeks apart. A third dose of any COVID-19 vaccine is recommended 6 months after the initial series is completed (with a minimum interval of 2 months between doses if using Nuvaxovid).
Last reviewed:
November 16, 2025
The benefit of COVID-19 vaccination to an individual patient varies depending on the health status of the patient, their history of vaccination and COVID-19 infection, and the circulating COVID-19 strains. However, despite these variables, observational studies consistently show vaccination in all age groups provides measurable additional protection against hospitalization or death compared to those who are unvaccinated.
CDC published “Interim Estimates of 2024–2025 COVID-19 Vaccine Effectiveness Among Adults Aged ≥18 Years — VISION and IVY Networks, September 2024–January 2025” in MMWR on February 27, 2025 (www.cdc.gov/mmwr/volumes/74/wr/mm7406a1.htm). They concluded vaccine effectiveness (VE) of 2024–2025 COVID-19 vaccine was 33% against COVID-19–associated emergency department (ED) or urgent care (UC) visits among adults age18 years or older and 45%–46% against hospitalizations among immunocompetent adults age 65 years or older, compared with not receiving a 2024–2025 vaccine dose. VE against hospitalizations in immunocompromised adults age 65 years or older was 40%.
Last reviewed:
November 16, 2025
