COVID-19 Vaccine, mRNA (Moderna) (2026-2027 Formula)

Both are used for active immunization to prevent COVID-19 caused by SARS-CoV-2.

Spikevax is approved for people who are 65 years and older, or 6 months through 64 years of age with at least one underlying condition that puts them at high risk for severe outcomes from COVID-19.

mNEXSPIKE is approved for people who are 65 years and older, or 12 through 64 years of age with at least one such condition. It is not approved for anyone under 12.

Neither label lists which conditions count as high risk. Both point to the CDC's published list. The Spikevax label adds that prematurity has been linked to COVID-19 hospitalization in children aged 6 through 23 months.

What is in the 2026-2027 formula

Both vaccines have been updated for the 2026-2027 season and target the SARS-CoV-2 JN.1-descendent variant XFG.

The difference is how much of the virus's spike protein each one encodes. Spikevax carries instructions for the whole pre-fusion stabilized spike protein. mNEXSPIKE carries instructions for just two parts of it: the N-terminal domain and the receptor-binding domain. This narrower target is what allows mNEXSPIKE to use a smaller mRNA dose.

Before vaccinating

Screen everyone for contraindications and precautions first. Check that the syringe label says 2026-2027 Formula, and that the strength matches the person's age.

Have treatment for anaphylaxis immediately available. Fainting can happen with any injected vaccine, so have procedures in place to prevent injury.

Checking the vaccine

Both vaccines are a white to off-white suspension and may contain white or translucent particles from the product itself. Do not use a syringe that is discoloured or contains any other particles. Do not shake.

Route

Give by intramuscular injection only. Both come as single-dose prefilled syringes.

• Ask the recipient or caregiver to read the FDA-approved patient labeling.
• Explain the potential benefits and risks of vaccination.
• Ask them to report any adverse events to their healthcare provider, or to the Vaccine Adverse Event Reporting System (VAERS) at 1-800-822-7967 or vaers.hhs.gov. Reactions can also be reported to ModernaTX, Inc. at 1-866-663-3762.
• Ask them to mention any other medicines they take, including over-the-counter products and dietary or herbal supplements, and any current illness.
• Ask women to say if they are pregnant, plan to become pregnant, or plan to breastfeed.

Severe allergic reactions

Treatment for anaphylaxis must be immediately available whenever these vaccines are given.

Myocarditis and pericarditis

Postmarketing data on mRNA COVID-19 vaccines show an increased risk of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart). Symptoms usually begin in the first week after vaccination, and the risk is highest in males aged 12 through 24 years.

For the 2023-2024 formula of mRNA COVID-19 vaccines, health insurance claims data give an estimated unadjusted incidence in the 1 to 7 days after a dose of:

• about 8 cases per million doses in people aged 6 months through 64 years
• about 27 cases per million doses in males aged 12 through 24 years

Some people have needed intensive care, but symptoms typically resolve within a few days with conservative management.

Longer-term follow-up comes from a retrospective study of hospitalized patients diagnosed with vaccine-associated myocarditis. At a median of around 5 months after vaccination, abnormal cardiac MRI findings marking heart muscle injury were still common, although their severity had decreased over time. What these findings mean clinically is not known, and information on potential long-term effects is not yet available.

Fainting

Fainting can occur with any injected vaccine. Have procedures in place to prevent injury.

Weakened immune response

People who are immunocompromised, including those on immunosuppressive therapy, may not respond as strongly to either vaccine.

Limits of protection

Neither vaccine protects everyone who receives it.

Pregnancy

For both vaccines, the available data in pregnant women are insufficient to inform vaccine-associated risks in pregnancy.

In animal studies, female rats given the vaccine twice before mating and twice during gestation showed no evidence of harm to the fetus, no vaccine-related fetal malformations, no adverse effect on postnatal development, and no effect on female fertility.

Pregnant individuals infected with SARS-CoV-2 are at increased risk of severe COVID-19 compared with those who are not pregnant.

Breastfeeding

It is not known whether either vaccine passes into human milk, and there are no data on effects on the breastfed infant or on milk production. Weigh the benefits of breastfeeding alongside the mother's clinical need for the vaccine and any potential effects on the infant. For preventive vaccines, the underlying maternal condition is susceptibility to the disease being prevented.

Children

Spikevax: safety and effectiveness in children 6 months through 17 years with at least one high-risk factor is based on data in that age group and in adults. It has not been established in infants under 6 months.

mNEXSPIKE: safety and effectiveness in adolescents 12 through 17 years with at least one high-risk condition is based on data in that age group and in adults. It has not been established in anyone under 12.

Older adults

Studies of Spikevax and Moderna COVID-19 Vaccine, Bivalent included roughly 7,800 participants aged 65 and older and 1,400 aged 75 and older. Studies of mNEXSPIKE included roughly 1,801 aged 65 and older and 348 aged 75 and older.

For both vaccines, some local and systemic reactions were reported less often in people aged 65 and older than in those aged 18 through 64, and effectiveness was similar between the two groups.

Immunocompromised patients

The CDC publishes guidance on COVID-19 vaccination for people who are moderately to severely immunocompromised.

Do not give either vaccine to anyone with a known history of a severe allergic reaction, such as anaphylaxis, to any component of that vaccine.

• Spikevax is also contraindicated after a severe allergic reaction to a previous dose of any Moderna COVID-19 vaccine.
• mNEXSPIKE is also contraindicated after a severe allergic reaction to a previous dose of Spikevax, or of any Moderna COVID-19 vaccine authorized for emergency use.

The figures below are the reactions reported by 10% or more of clinical trial participants. Percentages are the highest reported across the studies for that age group.

Spikevax

mNEXSPIKE

Reported after marketing

Myocarditis, pericarditis, anaphylaxis, hives, fainting, and febrile seizures.

Spikevax

Children aged 6 through 23 months may need two doses. Everyone aged 2 and over receives a single dose.

From age 2 onward, the dose is the same regardless of COVID-19 vaccination history. If the person has had any COVID-19 vaccine before, give the dose at least 2 months after that last dose.

A child who turns 2 partway through a two-dose series should receive both doses as Spikevax.

mNEXSPIKE

Everyone aged 12 and over receives a single 0.2 mL dose, regardless of COVID-19 vaccination history. If the person has had any COVID-19 vaccine before, give the dose at least 3 months after that last dose.

Spikevax

• Store frozen at −50°C to −15°C (−58°F to 5°F).
• Once thawed, may be kept refrigerated at 2°C to 8°C (36°F to 46°F) for up to 60 days, or until the carton expiration date, whichever comes first.
• Once thawed, may be kept at 8°C to 25°C (46°F to 77°F) for up to 12 hours.
• Do not refreeze.

mNEXSPIKE

• Store refrigerated at 2°C to 8°C (36°F to 46°F). Do not freeze.
• May be kept at 8°C to 25°C (46°F to 77°F) for up to 12 hours.

For both vaccines, minimize exposure to room light during storage and avoid direct sunlight and ultraviolet light. Syringes can be handled in room light.

Both are nucleoside-modified mRNA vaccines formulated in lipid particles.

After the injection, the lipid particles carry the mRNA into cells, where it is translated into the spike protein antigen. The immune system recognizes that antigen as foreign and mounts a response, which protects against COVID-19.

The mRNA in Spikevax encodes the pre-fusion stabilized spike glycoprotein of the SARS-CoV-2 JN.1-descendent variant XFG. The mRNA in mNEXSPIKE encodes the N-terminal domain and receptor-binding domain of the spike glycoprotein of the same variant.

Spikevax arrives frozen and must be thawed before use. Follow the thawing times in the prescribing information. Once thawed, it must not be refrozen.

mNEXSPIKE arrives refrigerated and must never be frozen. No thawing is needed. The frozen presentation and its thawing instructions were removed from the label in August 2026.

Manufactured for Moderna US, Inc., Princeton, NJ 08540. Spikevax and mNEXSPIKE are trademarks of ModernaTX, Inc.