A Study of mRNA-1608, a Herpes Simplex Virus -2 (HSV-2) Therapeutic Candidate Vaccine, in Healthy Adults 18 to 55 Years of Age With Recurrent HSV-2 Genital Herpes

Study at a glance

From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title

A Phase 1/2, Randomized, Observer-Blind, Controlled, Dose-Ranging Study of mRNA-1608, an HSV-2 Therapeutic Candidate Vaccine, in Healthy Adults 18 to 55 Years of Age With Recurrent HSV-2 Genital Herpes

ClinicalTrials.gov ID

NCT06033261

Acronym / sponsor ID

mRNA-1608-P101

Conditions

Genital Herpes

Keywords

HSV-2, Herpes Simplex Virus Type 2, HSV-2 vaccine, Genital Herpes, mRNA-1608

Phase

Phase 1/2

Study type

Interventional

Recruitment status

Completed

Enrolment

303 participants (actual)

Lead sponsor

ModernaTX, Inc.Industry (pharma, biotech, devices)

Study start

6 Sep 2023 (actual)

Primary completion

25 Apr 2025 (actual)

Study completion

25 Apr 2025 (actual)

First posted

13 Sep 2023 (actual)

Results

Posted 8 May 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose

Treatment

Allocation

Randomised

Intervention model

Parallel groups

Masking

Triple blind (participant, investigator, outcomes assessor)

Number of arms

4

Who may qualify

Ages

18 to 55 years

Sex

All

Healthy volunteers

Accepted

Age groups

Adult

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Primary outcome

1. Number of Participants With Solicited Local and Systemic ARs

   Time frame: Up to Day 64 (Within 7 days after study vaccination)

   Solicited ARs were collected in an electronic diary (eDiary). Local ARs: injection site pain, erythema (redness), swelling/induration (hardness); and axillary (underarm) swelling or tenderness ipsilateral to the side of injection. Systemic ARs: fever, headache, fatigue, myalgia, arthralgia, nausea/vomiting, and chills. Note, not all solicited ARs were considered adverse events (AEs). Investigator reviewed whether the solicited AR was also to be recorded as an AE. A Summary of serious AEs (SAEs) and nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

2. Number of Participants With Unsolicited Adverse Events (AEs)

   Time frame: Up to Day 85 (Up to 28 days after study vaccination)

   An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related. Any abnormal laboratory test result (hematology, clinical chemistry, or prothrombin time [PT]/partial thromboplastin time [PTT]) or other safety assessment (for example, electrocardiogram, radiological scan, vital sign measurement), including one that worsened from baseline and was considered clinically significant in the medical and scientific judgment of the Investigator was recorded as an AE. A summary of SAEs and all nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

3. Number of Participants With Serious Adverse Events (SAEs), Adverse Events of Special Interest (AESIs), and AEs Leading to Study Discontinuation

   Time frame: Day 1 through Day 393

   An SAE was defined as any AE that resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in disability, was a congenital anomaly/birth defect, or was an important medical event. An AESI was an AE (serious or nonserious) of scientific and medical concern specific to the Sponsor's product or program, for which ongoing monitoring and immediate notification by the Investigator to the Sponsor were required. A summary of SAEs and all nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

4. Number of Participants With Medically Attended AEs (MAAEs)

   Time frame: Day 1 through Day 393

   A MAAE is an AE that led to an unscheduled visit to a healthcare practitioner. A summary of SAEs and all nonserious AEs ("Other"), regardless of causality, is located in the "Reported Adverse Events" section.

Results and safety

Loading the posted results from ClinicalTrials.gov…

Research links

• Official record on ClinicalTrials.govLast updated by the sponsor 8 May 2026.
• Posted resultsParticipant flow, baseline, all outcome measures and adverse events.

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

23 sites in 1 country: see every site and its status.