Enterovirus 71 Inactivated VaccinePhase 3NCT07178522
A Study to Evaluate the Immunogenicity and Safety of an EV71 Vaccine (Envacgen®) in Children Aged 6 to <10 Years Compared to Children Aged 2 to <6 Years
A Phase 3 study testing Envacgen® in people with Enterovirus 71 Inactivated Vaccine, run by Medigen Vaccine Biologics Corp. at 3 sites in Taiwan.
Trial summary
The purpose of this study is to assess the immunogenicity and safety of EV71 vaccine (Envacgen®) in Children Aged 6 to <10 Years compared to Children Aged 2 to <6 Years. Read more about this study
- Who is it for?
- Ages 2 to 9 yearsHealthy volunteers can take part
- Conditions the study is for
- Enterovirus 71 Inactivated Vaccine
- What is being tested?
- Envacgen®
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 379 participants
- Where
- 3 sitesTaiwan
- Study dates
- 25 Jun 2025to 31 Oct 2026
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 2 to 9 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- Healthy children aged 2 to <10 years as established by medical history and clinical examination.
- Subject and/or the subject's parent/guardian is able to understand and sign the ICF.
Who cannot join
- Has poor venous access.
- Currently has a fever defined as ear/rectal temperature ≥ 38°C or axillary temperature ≥ 37.5 °C within 2 days before the time of planned vaccination.
- Has had previously known exposure to EV71 or has received EV71 vaccine.
- Has a history of herpangina or HFMD associated with enterovirus infection in the past 28 days before the date of planned study drug vaccination.
- Has been diagnosed with a significant neurological, pulmonary, cardiovascular, hematological, hepatic, or renal disorder.
- Has a history of hypersensitivity to vaccines, or a history of allergic disease or reactions likely to be exacerbated by any component or any residual trace components such as formaldehyde of the Envacgen® vaccine.
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- Has used any investigational/nonregistered product (including drug, vaccine, or invasive medical device) within 28 days before study vaccination or plans to use any of them during the study period.
- Has confirmed or suspected autoimmune disorder or immunodeficiency.
- Has been administered or plans to be administered with any licensed live attenuated vaccine within 14 days before or after each study vaccination.
- Has used immunoglobulins via intravenous route or any blood products within 11 months before vaccination or plans to use any of them during the study period.
- Has received immunosuppressant, cytotoxic drug, corticosteroid (including prednisolone ≥ 0.5 mg/kg/day or equivalent), immunomodulator or acetylsalicylic acid for > 14 days within 6 months before the first vaccination or plans to use any of them during the study period. (Inhaled and topical steroids are allowed).
- Has any medical or psychiatric condition that is a contraindication to protocol participation based on the judgment of the Investigator.
Trial locations and contacts
3 sites in 1 country.
Taiwan3 sites
National Taiwan University Hospital Hsin-Chu Branch
Hsinchu
National Taiwan University Hospital
Taipei
Chang Gung Medical Hospital Linkou
Taoyuan
About this study
Official title: A Prospective, Open-label, Multi-center, Phase 3 Study to Evaluate the Immunogenicity and Safety of an Inactivated EV71 Enterovirus Vaccine (Envacgen®) in Children Aged 6 to <10 Years Compared to Children Aged 2 to <6 Years
The purpose of this study is to assess the immunogenicity and safety of EV71 vaccine (Envacgen®) in Children Aged 6 to <10 Years compared to Children Aged 2 to <6 Years.
Read the detailed description
This is a prospective, open-label, multi-center, phase 3 study. Participants will receive the first IM injection of study vaccine on Day 1 and will receive a second dose 56 days later. The last study visit is on Day 237 when participants will be contacted via telephone to assess for adverse events .
- Conditions
- Enterovirus 71 Inactivated Vaccine
- Being tested
- Envacgen®
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Envacgen®Biological
Subjects are to receive a 0.5 mL IM injection of Envacgen®. Study drug is administered on Day 1 and Day 57 of the study.
| Study group | Role | What they receive |
|---|---|---|
| Children Aged 6 to <10 Years | Experimental | EV71 Vaccine (Envacgen®) Receives: Biological: Envacgen® |
| Children Aged 2 to <6 Years | Active comparator | EV71 Vaccine (Envacgen®) Receives: Biological: Envacgen® |
What is being measured
The primary outcome is the main question the study is designed to answer.
Immunogenicity of Envacgen®
- Geometric Mean Titer (GMT) of Neutralizing Antibody (NTAb) Measurement of NTAb titers against EV71 at 28 days after the second dose of Envacgen® in children aged 6 to <10 years (Old group) compared with children aged 2 to <6 years (Young group).
- Seroresponse Rate (SRR) of Neutralizing Antibody (NTAb) Percentage of participants with seroresponse (defined as at least a four-fold increase from baseline in NTAb titers) at 28 days after the second dose of Envacgen® in children aged 6 to <10 years (Old group) compared with children aged 2 to <6 years (Young group).
Measured: Day 1 to 28 days after the second vaccination.
Incidence of Adverse Events(AEs) [Safety]
Number and percentage of participants in the Old group (6 to <10 years) and Young group (2 to <6 years) with any reported adverse events within 28 days after vaccination with Envacgen®.
Measured: Day 1 to 28 days after the second vaccination.
Secondary outcomes (1)
Incidence of Adverse Events(AEs) [Safety]
Number of participants with any adverse events (AEs) reported during the study period.
Measured: Day 1 to 180 days after the second vaccination.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Sep 2025
- Study start25 Jun 2025
- Primary completion2 Jul 2026
- Study completion31 Oct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Enterovirus 71 Inactivated VaccineStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 379 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medigen Vaccine Biologics Corp.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07178522
- Sponsor's protocol ID
- CT-EV-32
- Status last verified
- Oct 2026
- First submitted
- 21 Aug 2025
- Last updated
- 7 Oct 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective, Open-label, Multi-center, Phase 3 Study to Evaluate the Immunogenicity and Safety of an Inactivated EV71 Enterovirus Vaccine (Envacgen®) in Children Aged 6 to <10 Years Compared to Children Aged 2 to <6 Years
- ClinicalTrials.gov ID
- NCT07178522
- Acronym / sponsor ID
- CT-EV-32
- Conditions
- Enterovirus 71 Inactivated Vaccine
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 379 participants (actual)
- Lead sponsor
- Medigen Vaccine Biologics Corp.Industry (pharma, biotech, devices)
- Study start
- 25 Jun 2025 (actual)
- Primary completion
- 2 Jul 2026 (actual)
- Study completion
- 31 Oct 2026 (estimated)
- First posted
- 17 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to assess the immunogenicity and safety of EV71 vaccine (Envacgen®) in Children Aged 6 to <10 Years compared to Children Aged 2 to <6 Years.
Detailed description
This is a prospective, open-label, multi-center, phase 3 study. Participants will receive the first IM injection of study vaccine on Day 1 and will receive a second dose 56 days later. The last study visit is on Day 237 when participants will be contacted via telephone to assess for adverse events .
Study design
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Children Aged 6 to <10 Years | Experimental | Biological: Envacgen®EV71 Vaccine (Envacgen®) |
| Children Aged 2 to <6 Years | Active comparator | Biological: Envacgen®EV71 Vaccine (Envacgen®) |
Who may qualify
- Ages
- 2 to 9 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (2 listed)
- Healthy children aged 2 to <10 years as established by medical history and clinical examination.
- Subject and/or the subject's parent/guardian is able to understand and sign the ICF.
Key exclusion criteria (12 listed)
- Has poor venous access.
- Currently has a fever defined as ear/rectal temperature ≥ 38°C or axillary temperature ≥ 37.5 °C within 2 days before the time of planned vaccination.
- Has had previously known exposure to EV71 or has received EV71 vaccine.
- Has a history of herpangina or HFMD associated with enterovirus infection in the past 28 days before the date of planned study drug vaccination.
- Has been diagnosed with a significant neurological, pulmonary, cardiovascular, hematological, hepatic, or renal disorder.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Envacgen®Subjects are to receive a 0.5 mL IM injection of Envacgen®. Study drug is administered on Day 1 and Day 57 of the study. | Biological | Children Aged 2 to <6 Years, Children Aged 6 to <10 Years |
Primary outcome
Immunogenicity of Envacgen®
Time frame: Day 1 to 28 days after the second vaccination.
1. Geometric Mean Titer (GMT) of Neutralizing Antibody (NTAb) Measurement of NTAb titers against EV71 at 28 days after the second dose of Envacgen® in children aged 6 to <10 years (Old group) compared with children aged 2 to <6 years (Young group). 2. Seroresponse Rate (SRR) of Neutralizing Antibody (NTAb) Percentage of participants with seroresponse (defined as at least a four-fold increase from baseline in NTAb titers) at 28 days after the second dose of Envacgen® in children aged 6 to <10 years (Old group) compared with children aged 2 to <6 years (Young group).
Incidence of Adverse Events(AEs) [Safety]
Time frame: Day 1 to 28 days after the second vaccination.
Number and percentage of participants in the Old group (6 to <10 years) and Young group (2 to <6 years) with any reported adverse events within 28 days after vaccination with Envacgen®.
1 secondary outcome
Incidence of Adverse Events(AEs) [Safety]
Time frame: Day 1 to 180 days after the second vaccination.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Oct 2026.
- Individual participant dataSharing planned: No
Related trials for Enterovirus 71 Inactivated Vaccine
Not yet recruiting
Bridging Clinical Trial of EV71 Vaccine in Vietnamese Children
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Protective Efficacy , Immunogenicity and Safety of the Tetravalent Inactivated Enterovirus Vaccine (Vero Cell).
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Enrolling by invitationObservational study
Study on the Persistence of Immunity Following EV71 Vaccination
Hand, Foot, and Mouth Disease, Hand, Foot, and Mouth Disease (HFMD)
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Efficacy, Safety, and Immunogenicity of the Bivalent Inactivated Enterovirus Vaccine (Vero Cell)
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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.
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Envacgen® in people with Enterovirus 71 Inactivated Vaccine, run by Medigen Vaccine Biologics Corp. at 3 sites in Taiwan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 7 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Taiwan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Immunogenicity of Envacgen® (time frame: Day 1 to 28 days after the second vaccination.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Oct 2026.