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A clinical trial of an Epstein-Barr virus (EBV) vaccine for teens

Trial ID: NCT05164094 (Part B)
The Eclipse Trial is a Phase 1 clinical trial conducted by Moderna to evaluate the safety of and immune response to an investigational vaccine, called mRNA-1189, that aims to protect teens ages 12–17 against Epstein-Barr virus (EBV) and infectious mononucleosis (mono).

Trial Details

The Eclipse Trial is evaluating the safety and immune response of an investigational vaccine, called mRNA-1189, which aims to protect against Epstein-Barr virus (EBV) and infectious mononucleosis (mono). An investigational vaccine is a vaccine that has not been approved by a country’s regulatory agency, like the U.S. Food and Drug Administration (FDA).

Mono can cause fever, tiredness (fatigue), sore throat, and swollen lymph nodes. It can also cause prolonged fatigue and sometimes an enlarged spleen, which can limit activity and, rarely, may require hospitalization. Mono is most often associated with EBV infection, which results in lifelong infection and the possibility of developing other diseases. Currently, there is no approved vaccine for EBV.

Mono is easily transmissible and causes those who are infected a lot of hardship and inconveniences. People can spend up to two weeks in bed, which means missed appointments, missed work or school, and missing out on life in general.

Estimated Enrollment

150 Participants



Eligibility Criteria

Participants must:

  • Be 12 to 17 years of age
  • Be in generally good health
  • Be willing and able to comply with trial requirements

Participants must not:

  • Have been exposed to someone with COVID-19 within 14 days before screening
  • Be pregnant or breastfeeding

Site Locations

Participants will need to go to one of the clinics taking part in this clinical trial.

Sites are located in the cities/states identified with the red pin:

What to Expect

Participation in the Eclipse Trial will last approximately 19 months and includes 15 visits to a clinical trial site and 10 phone calls with the clinical trial team.

Participants will be given a total of 3 injections in the upper arm, each during separate visits.

Participants will be randomly assigned to receive 1 of 4 different dose amounts of the investigational mRNA-1189 vaccine or a placebo. A placebo is a solution that contains no active ingredients and is used as a comparison to understand whether the investigational vaccine works and is safe. All clinical trial participants will get the same level of trial-related care regardless of which injection or dose they receive.

Participation in the Eclipse Trial includes 3 parts:

  • Screening: During this period, which lasts up to 28 days, the trial team performs tests and procedures to make sure the clinical trial is a good match for the potential participant.
  • Dosing period: During this period, the participant has 3 injection visits to receive the investigational vaccine or the placebo. This period lasts approximately 6 months.
  • Follow-up observation period: This period lasts up to 11 months after the last dose of the investigational vaccine or placebo. During this period, the participant monitors their health for side effects and mono symptoms.

Participants will be asked to use an eDiary app on their smartphone (or a provided device) to report any side effects they might experience every day for 7 days after receiving each of the injections.

Insurance is not needed to participate, and all trial-related procedures and exams will be covered at no cost. Qualified participants will receive payment for their trial-related time and travel.

Frequently Asked Questions (FAQs)