A Phase 3 interventional study of NBP608 (Mid Potency) and NBP608 (Low Potency) in Varicella (Chickenpox), sponsored by SK Bioscience Co., Ltd.. Recruiting at 14 sites in 4 countries. Open to participants aged 12 Months to 12 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-15.
Sponsored by SK Bioscience Co., Ltd. (part of SK Chemicals Co., Ltd.) · Phase 3, Interventional, and Prevention
The goal of this study is to evaluate the safety and immunogenicity of an investigational varicella vaccine in children. Researchers will compare the investigational vaccine, NBP608, with licensed varicella vaccines. The study includes children aged 12 months to 12 years.
Participants will be randomly assigned to receive either the investigational vaccine (NBP608) or licensed varicella vaccines.
Participants will:
Receive two subcutaneous injections of a study vaccine administered. Visit the study clinic seven times over approximately 15 months. Receive follow-up phone calls 7 days after each vaccination to monitor for safety.
This is a Phase III, randomized, Double-blinded, Active-controlled, Multinational, Multicenter study designed to evaluate the safety and immunogenicity of a two-dose regimen of NBP608 in children aged 12 months to 12 years.
Immunogenicity will be assessed using blood samples collected at predefined time points to evaluate immune responses to varicella.
Safety will be evaluated throughout the study by monitoring adverse events (AEs), serious adverse events (SAEs), and adverse events of special interest (AESIs) following vaccination.
Each participant will take part in the study for approximately 15 months, including scheduled clinic visits and follow-up assessments.
180 studies on the registry are indexed under Chickenpox; 28 are open to participants now.
This study's planned enrollment of 780 is above the median of 475 across 149 interventional studies indexed under Chickenpox.
Browse Chickenpox studies →SK Bioscience Co., Ltd. is the lead sponsor of 12 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
1. Participants with any acute illness, including fever or symptoms, at the time of study vaccination. 2. History of varicella-zoster virus (VZV) infection or recent exposure to VZV.
3. Presence of household contacts at high risk for severe VZV infection 4. History of immunodeficiency, disease, or other conditions affecting the immune system.
5. History of bleeding disorders contraindicating vaccination. 6. History of severe allergic reactions to vaccines or vaccine components. 7. History of Guillain-Barré syndrome associated with prior vaccination. 8. Active untreated tuberculosis infection. 9. Any significant medical condition that, in the investigator's judgment, may interfere with study participation or interpretation of results.
10. Prior receipt of any varicella-containing vaccine. 11. Receipt or planned use of vaccines, medications, immunoglobulins, blood products, or therapies that may interfere with study evaluation, as defined in the protocol.
12. Participation in another clinical study involving an intervention within a protocol-defined timeframe.
13. Study staff, investigators, and their immediate family members.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive either a one-dose regimen or a two-dose regimen consisting of two subcutaneous injections administered.
Biological: NBP608 (Mid Potency) · Other: Normal Saline (Placebo)
Participants receive either a one-dose regimen or a two-dose regimen consisting of two subcutaneous injections administered.
Biological: NBP608 (Low Potency) · Other: Normal Saline (Placebo)
Participants receive either a one-dose regimen or a two-dose regimen consisting of two subcutaneous injections administered.
Biological: Varivax® · Other: Normal Saline (Placebo)
Participants receive either a one-dose regimen or a two-dose regimen consisting of two subcutaneous injections administered.
Biological: SKYVaricella® · Other: Normal Saline (Placebo)
NBP608 (mid potency) is a live attenuated varicella virus vaccine (Oka/SK strain).
NBP608 (low potency) is a live attenuated varicella virus vaccine (Oka/SK strain).
Varivax® is a licensed live attenuated varicella virus vaccine (Oka/Merck strain).
SKYVaricella® is a licensed live attenuated varicella virus vaccine (Oka/SK strain).
Placebo consisting of normal saline (0.9% sodium chloride solution).
Seroconversion rate of varicella-zoster virus(VZV)
Seroconversion rate of varicella-zoster virus(VZV) IgG antibodies at 6 weeks after each vaccination
Time frame: 6 weeks after each dose.
Geometric mean antibody titer (GMT) of varicella-zoster virus(VZV) IgG antibodies
Geometric mean antibody titer (GMT) of varicella-zoster virus(VZV) IgG antibodies at 6 weeks after the second vaccination
Time frame: 6 weeks after the second dose.
Seroconversion Rates
Proportion of participants who are seronegative prior to vaccination at each specified assessment time point.
Time frame: Time Frame: 6 weeks after each vaccination, 6 months after the second vaccination
Geometric Mean Titers (GMTs)
VZV IgG antibodies at each specified time point.
Time frame: 6 weeks after each vaccination, 6 months after the second vaccination
Geometric Mean Fold Rise (GMFR)
Fold increases in VZV IgG antibody titers
Time frame: from baseline to each post-vaccination timepoint
Geometric Mean Fold Reduction (GMFRd)
Fold reductions in VZV IgG antibody titers
Time frame: from baseline to each post-vaccination timepoint
Immediate reactions
Percentage of participants reporting any immediate reactions following each vaccination.
Time frame: Within 30 minutes
Solicited adverse events
Percentage of participants reporting solicited adverse events following each vaccination.
Time frame: Within 14 days
Unsolicited adverse events
Percentage of participants experiencing any unsolicited adverse events following each vaccination.
Time frame: Within 42 days
Serious adverse events, medically attended AEs, and AEs leading to withdrawal
Percentage of participants experiencing any serious adverse events, medically attended adverse events, or adverse events leading to withdrawal during the study period.
Time frame: during study period
Adverse events of special interest
Percentage of participants experiencing any adverse events of special interest during the study period.
Time frame: during the study period
Plan to share: No
No publications or documents are linked to this record.
Started Jul 2026 (actual). Primary completion is estimated for Feb 2027, 7 months after the start.
Of 35 industry-sponsored phase 3 interventional studies under Chickenpox, half reached primary completion within 12 months of starting (the median), counting those still running; a quarter within 8 and three quarters within 15. This study's planned 7 months is below that.
Counting every sponsor, half of 39 studies reached it within 13 months; a quarter within 9 and three quarters within 24.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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Studies of the drugs tested here: NBP608 · Chickenpox Vaccine