Inclusion Criteria:
1. Female or male patients aged 40-75 years old. Refer to section 5.3 for reproductive criteria for male and female participants
2. Diagnosed with idiopathic PD within the previous 4 years based on the MDS-PD criteria. The diagnosis must be confirmed by bradykinesia plus one of the other cardinal signs (resting tremor, rigidity or postural instability not caused by primary visual, vestibular, cerebellar, or proprioceptive dysfunction) being present
3. Severity ≤2 in the modified Hoehn and Yahr scale
4. Brain magnetic resonance imaging (MRI) results should be consistent with the diagnosis of PD
5. If on symptomatic PD medications (L-DOPA (+/- benserazide, carbidopa), COMT inhibitors (entacapone, opicapone), dopamine agonists (pramipexol, ropinirole, rotigotine, apomorphine), MAO-B inhibitors (safinamid, selegiline, rasagiline) or NMDA receptor antagonists (amantadine)), doses must be stable for at least 3 months before study entry
6. Understands and agrees to comply with the study procedures and provides written informed consent
Exclusion Criteria:
1. Known or suspected allergy, or history of anaphylaxis, to vaccines or their excipients, or kanamycin, if considered relevant by the investigator
2. Presence or history of autoimmune disease or immunodeficiency, if considered relevant by the investigator
3. Presence of active infectious disease (hepatitis B, hepatitis C, or human immunodeficiency virus (HIV))
4. Significant cognitive impairment or clinical dementia, or a Montreal Cognitive Assessment (MoCA) score \<26
5. High suspicion of other parkinsonian syndromes, such as multiple system atrophy, progressive supranuclear palsy, drug induced Parkinsonism and post-encephalitic Parkinsonism
6. Any relevant systemic illness. This includes cardiovascular, hepatic, gastroenterological, respiratory, endocrinological, hematologic disease, or any other condition that, in the investigator's opinion, could interfere with the analyses of safety and efficacy in this study, unless patient has been on stable doses of medication for any of these concurrent illnesses for at least 3 months prior to study entry
7. Unstable psychiatric illness, including psychosis, suicidal ideation, untreated major depression, schizophrenia, or bipolar affective disorder within 90 days before Visit 1, as determined by the investigator
8. History of drug or alcohol abuse within the past 5 years
9. Recent history (≤2 years) of cancer (exceptions: basal cell carcinoma, intraepithelial cervical neoplasia)
10. Contraindication for MRI or lumbar puncture
11. Female patients who are pregnant or lactating
12. Birthmarks, tattoos, wounds, or skin conditions that may obscure the assessment of injection site reactions
13. Participation in the active treatment phase of any non-PD clinical trial within 30 days prior to Visit 1
14. Prior treatment with experimental immunotherapeutics for PD, immunosuppressive drugs or treatment with deep brain stimulation. Patient has received or plans to receive any vaccine other than study intervention within 28 days before or 28 days after each study vaccination.
15. Employee at the study site, spouse/partner or relative of any study staff (e.g., investigator, sub-investigators, or study nurse) or relationship to the sponsor
