mRNA-1273.214 Vaccine for COVID-19 in Children

No longer recruiting at 90 trial locations

Overseen By Moderna WeCare Team

Age: < 18

Sex: Any

Trial Phase: Phase 3

Sponsor: ModernaTX, Inc.

Must not be taking: Immunosuppressants, Monoclonal antibodies

Disqualifiers: SARS-CoV-2 infection, Immunodeficiency, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Approved in 4 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: 3

Duration: 4 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests new COVID-19 vaccines in young children to assess their safety and effectiveness in boosting the immune system. It focuses on children aged 6 months to under 6 years, evaluating their response to either a new vaccine or a booster shot if they have already received a COVID-19 vaccine. Children without a previous COVID-19 infection and with stable health conditions like asthma or diabetes may be suitable candidates. The research aims to enhance protection for children against COVID-19 variants. As a Phase 3 trial, this study represents the final step before FDA approval, offering an opportunity to contribute to vital research that could soon lead to widespread vaccine availability for children.

Will I have to stop taking my current medications?

The trial protocol does not specify if you need to stop taking your current medications. However, certain medications like systemic immunosuppressants or immune-modifying drugs may affect eligibility if taken in the 6 months prior to enrollment. It's best to discuss your specific medications with the trial team.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that the mRNA-1273.214 vaccine, used as a booster, is safe for children aged 6 months to 5 years. Most side effects, such as soreness at the injection site or mild fever, are common and resolve quickly. The vaccine targets two virus strains and has been well-tolerated in young children, with no serious safety issues reported.

For the mRNA-1273.815 vaccine, studies have supported its safety in children under 5 years. It effectively prevents COVID-related hospital visits without major safety concerns. Most side effects are mild and temporary, similar to those seen with other vaccines.

Both vaccines have been tested in similar age groups and have demonstrated good safety profiles. While these vaccines remain under study, current research suggests they are well-tolerated in young children. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about the mRNA-1273.214 and mRNA-1273.815 vaccines because they are designed to provide targeted protection against COVID-19 in children, using the cutting-edge mRNA technology seen in previous vaccines like those from Pfizer and Moderna. Unlike traditional vaccines that use weakened viruses, these vaccines deliver genetic instructions to our cells to produce a harmless piece of the virus, prompting an immune response. The mRNA-1273.214 vaccine is unique because it offers a booster option for those who have already received the original mRNA-1273 vaccine, potentially enhancing immunity. Meanwhile, mRNA-1273.815 stands out by aiming to deliver robust protection even in those who have been vaccinated with other authorized COVID-19 vaccines, possibly increasing the breadth of immune defense.

What evidence suggests that this trial's treatments could be effective for COVID-19 in children?

This trial will evaluate the mRNA-1273.214 and mRNA-1273.815 vaccines in children. Research has shown that the mRNA-1273.214 vaccine works well in children aged 6 months to 11 years, similar to its effectiveness in adults. Studies indicate that the vaccine generates a strong immune response in the blood, with success rates up to 90.9%, effectively helping to protect against COVID-19.

For the mRNA-1273.815 vaccine, evidence supports its ability to prevent hospital visits and serious COVID-19 cases across various groups, including young children. Specifically, the vaccine has greatly reduced COVID-19-related hospitalizations, providing strong protection for children aged 6 months to 4 years. Participants in this trial will receive either the mRNA-1273.214 or mRNA-1273.815 vaccine, depending on their previous vaccination status and the specific trial arm to which they are assigned. ^{2 3 4 6 7}

Are You a Good Fit for This Trial?

Healthy children aged 6 months to less than 6 years, with normal growth standards, who have either not received a COVID-19 vaccine or had two doses of mRNA-1273 at least four months prior. Children with stable chronic diseases can join. Those acutely ill, febrile, or previously infected with SARS-CoV-2 within the last 90 days are excluded.

Inclusion Criteria

My chronic condition (like asthma or diabetes) has been stable for at least 6 months.

I received two doses of the mRNA-1273 vaccine, 28-35 days apart, at least 4 months ago.

I am 2 years or older with a healthy weight, or under 2 with proper height and weight.

Exclusion Criteria

I haven't taken immune-suppressing drugs for more than 2 weeks in the last 6 months.

I have not been seriously ill or had a fever in the last 24 hours.

I have received a COVID-19 vaccine that is not mRNA-1273.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive mRNA-1273.214 or mRNA-1273.815 vaccines as per their cohort assignment

4 weeks

2 visits (in-person)

Booster Dose Administration

Participants receive a booster dose of mRNA-1273.214 or mRNA-1273.815 vaccine

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and immunogenicity after vaccine administration

6 months

Multiple visits (in-person and virtual)

What Are the Treatments Tested in This Trial?

Interventions

• mRNA-1273.214

Trial Overview The trial is testing the safety and immune response to the mRNA-1273.214 COVID-19 vaccine in young children. It involves two parts: one for those who haven't been vaccinated and another for those previously given two doses of mRNA-1273 as a primary series.

How Is the Trial Designed?

Group I: mRNA-1273.815 (Part 4) Experimental Treatment 1 Intervention

Participants in Part 4 Cohort A will receive a single IM injection of mRNA-1273.815 vaccine on Day 1. Participants in Part 4 Cohort B will receive IM injections of mRNA-1273.815 vaccine on Day 1 and Day 29.

Group II: mRNA-1273.815 (Part 3) Experimental Treatment 1 Intervention

Participants who have previously been vaccinated with an authorized/approved COVID-19 vaccine, will receive a single IM BD of mRNA-1273.815 vaccine on BD Day 1, at least 4 months after the last dose of a COVID-19 vaccine.

Group III: mRNA-1273.214 (Part 2) Experimental Treatment 1 Intervention

Participants who have previously been vaccinated with a mRNA-1273 primary series, will receive a single IM BD of mRNA-1273.214 vaccine at least 4 months after completion of the mRNA-1273 primary series.

Group IV: mRNA-1273.214 (Part 1) Experimental Treatment 1 Intervention

Participants who have not been previously vaccinated against SARS-CoV-2, will receive 2 intramuscular (IM) injections of mRNA-1273.214 vaccine on Day 1 and Day 29.

mRNA-1273.214 is already approved in European Union, United Kingdom, United States for the following indications:

Approved in European Union as mRNA-1273.214 for:

• Prevention of COVID-19 caused by SARS-CoV-2 variants including Omicron BA.1 and BA.4/5

Approved in United Kingdom as mRNA-1273.214 for:

• Prevention of COVID-19 caused by SARS-CoV-2 variants including Omicron BA.1 and BA.4/5

Approved in United States as mRNA-1273.214 for:

• Prevention of COVID-19 caused by SARS-CoV-2 variants including Omicron BA.1 and BA.4/5

Who Is Running the Clinical Trial?

ModernaTX, Inc.

Lead Sponsor

Trials

127

Recruited

66,790,000+

Dr. Stephen Hoge

ModernaTX, Inc.

Chief Medical Officer

MD from Harvard Medical School

Stéphane Bancel

ModernaTX, Inc.

Chief Executive Officer since 2011

MBA from Harvard Business School, MSc in Engineering from École Centrale Paris

Published Research Related to This Trial

The mRNA-1273 vaccine (50 μg) was found to be safe for children aged 6 to 11, with mainly low-grade side effects like injection-site pain and fatigue, and no serious adverse events reported.

The vaccine demonstrated an efficacy of 88.0% in preventing Covid-19 in children, with immune responses comparable to those seen in young adults, indicating it is effective for this age group.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evaluation of mRNA-1273 Covid-19 Vaccine in Children 6 to 11 Years of Age. Creech, CB., Anderson, E., Berthaud, V., et al.[2023]

Bivalent vaccines encoding spike proteins from both the original Wuhan strain and Omicron variants (BA.1 or BA.4/5) induced broader neutralizing antibody responses in mice compared to monovalent vaccines, suggesting enhanced immunogenicity.

Boosting with these bivalent vaccines provided greater protection against BA.5 infection and reduced lung inflammation, indicating their potential effectiveness against currently circulating SARS-CoV-2 variants.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Bivalent SARS-CoV-2 mRNA vaccines increase breadth of neutralization and protect against the BA.5 Omicron variant. Scheaffer, SM., Lee, D., Whitener, B., et al.[2023]

A booster dose of the mRNA-1273 COVID-19 vaccine significantly increased neutralizing antibody levels against the original virus and key variants of concern, indicating enhanced immune response after waning immunity from the initial two-dose series.

Both the mRNA-1273 booster and variant-modified boosters were found to be safe and well-tolerated, suggesting they could be effective options for improving protection against emerging SARS-CoV-2 variants.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety and immunogenicity of SARS-CoV-2 variant mRNA vaccine boosters in healthy adults: an interim analysis. Choi, A., Koch, M., Wu, K., et al.[2021]

The bivalent mRNA-1273 COVID-19 vaccine shows a 70.3% effectiveness in preventing hospitalization for COVID-19 compared to individuals who received at least two doses of any monovalent mRNA vaccine, based on a matched cohort study.

The bivalent vaccine also provides significant protection against medically attended SARS-CoV-2 infections (55.0% effectiveness) and COVID-19 related hospital deaths (82.7% effectiveness), with durable protection lasting at least three months after the booster.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

mRNA-1273 bivalent (original and Omicron) COVID-19 vaccine effectiveness against COVID-19 outcomes in the United States. Tseng, HF., Ackerson, BK., Sy, LS., et al.[2023]

mRNA vaccines BNT162b2 and mRNA-1273 are effective in preventing SARS-CoV-2 infection in children and adolescents, significantly reducing the risk of severe disease and hospitalization.

While common side effects include pain, fatigue, and headache, serious side effects like myocarditis and pericarditis are rare, and monitoring can help mitigate risks.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

SARS-CoV-2 vaccines in children and adolescents: Can immunization prevent hospitalization? Liang, KH., Hung, KF., Wang, ML., et al.[2023]

The mRNA-1273 Covid-19 vaccine was found to be safe for children aged 6 months to 5 years, with mostly low-grade and transient adverse events, and no new safety concerns identified during the trial.

The vaccine elicited immune responses in young children that were comparable to those in young adults, meeting noninferiority criteria, with estimated efficacy rates of 36.8% for children aged 2-5 years and 50.6% for those aged 6-23 months against Covid-19.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evaluation of mRNA-1273 Vaccine in Children 6 Months to 5 Years of Age. Anderson, EJ., Creech, CB., Berthaud, V., et al.[2023]

The bivalent COVID-19 vaccine candidate mRNA-1273.211, which targets both the ancestral SARS-CoV-2 and the Beta variant, demonstrated higher neutralizing antibody responses compared to the original mRNA-1273 booster, indicating its potential effectiveness against multiple variants.

The safety profile of the mRNA-1273.211 booster was similar to that of the original mRNA-1273 booster, suggesting that it is a safe option for enhancing immunity against COVID-19 without increasing adverse effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety, immunogenicity and antibody persistence of a bivalent Beta-containing booster vaccine against COVID-19: a phase 2/3 trial. Chalkias, S., Eder, F., Essink, B., et al.[2023]

In a study of 604 adolescents in Riyadh, Saudi Arabia, the most common side effects reported after receiving the Pfizer-BioNTech and Spikevax COVID-19 vaccines were pain at the injection site, fatigue, and headaches, with 85.1% and 79.8% reporting pain after the first and second doses, respectively.

Adolescents with chronic diseases experienced significantly higher odds of specific side effects, such as menstrual disorders and breathing congestion, compared to those without chronic conditions, highlighting the need for tailored information regarding vaccine side effects based on individual health status.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evaluate the side effect associated with COVID-19 vaccine on adolescents in Riyadh, Saudi Arabia: A cross-section study. Aldali, JA., Alotaibi, FT., Alasiri, GA., et al.[2022]

The FDA authorized bivalent COVID-19 vaccines from Pfizer-BioNTech and Moderna, which target both the original virus and the Omicron variants, for booster doses in individuals aged 12 and older, with over 14 million doses administered by October 2022.

Safety data from the CDC indicated that while injection site and systemic reactions were common (60.8% and 54.8% respectively), serious adverse events were rare (4.5%), and overall, the side effects were consistent with those from previous monovalent vaccines, suggesting a favorable safety profile.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety Monitoring of Bivalent COVID-19 mRNA Vaccine Booster Doses Among Persons Aged ≥12 Years - United States, August 31-October 23, 2022. Hause, AM., Marquez, P., Zhang, B., et al.[2023]

Citations

1. fda.gov fda.gov/media/187814/download

July 9, 2025 Clinical Review Memo - SPIKEVAX P306 (P306) supported the safety and effectiveness of Spikevax in children 6 months through 11 years of age. 6.1 Study mRNA-1273-P204.

2. ema.europa.eu ema.europa.eu/en/medicines/human/EPAR/spikevax

Spikevax (previously COVID-19 Vaccine Moderna) - EMA These results indicate that the efficacy of Spikevax in children 6 months to 11 years old is similar to that in adults. Additional data showed that subsequent ...

3. products.modernatx.com products.modernatx.com/spikevaxpro/efficacy

Spikevax® (COVID-19 Vaccine, mRNA) Efficacy & Safety Seroresponse results: The rate difference was 53.9. Seroresponse was 90.9 (86.2, 94.4; 95% CI) for participants (n=209) who received the bivalent booster ( ...

4. thelancet.com thelancet.com/journals/laninf/article/PIIS1473-3099(24)00101-4/fulltext

Interim safety and immunogenicity of COVID-19 omicron ... Interim results from this trial show that both the mRNA-1273.214 primary series and booster dose were well tolerated by children, with no new ...

5. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10848053/

Effectiveness of Bivalent mRNA COVID-19 Vaccines in ... The adjusted bivalent COVID-19 vaccine effectiveness was 58.3% (95% CI, 34.0%-76.5%) for children aged 5 to 11 years and 47.5% (95% CI, 18.2%-

6. fda.gov fda.gov/media/155675/download

Package Insert - SPIKEVAX Safety data for a booster dose of bivalent vaccine (Original and Omicron BA.1) in individuals 6 months through 5 years of age were collected ...

7. ema.europa.eu ema.europa.eu/en/documents/product-information/spikevax-epar-product-information_en.pdf

Spikevax | EMA Safety data for Spikevax in children were collected in ... The safety, reactogenicity, and immunogenicity of a bivalent booster dose of Spikevax bivalent.