Significance or rationale of the study:

Virtual reality (VR) is a promising non-pharmacological pain management tool. It enhances motor function by promoting cortical reorganization and neuroplasticity. Its multimodal biofeedback engages sensory and cognitive functions, making therapy interactive, motivating, and easy to understand. With strong rehabilitation potential, VR helps patients adapt to real-world movements (Laver, 2020). Initially used for procedural pain management, VR is now expanding into chronic pain rehabilitation by encouraging engagement with difficult or avoided movements (Griffin et al., 2020). Additionally, VR offers a dynamic alternative to traditional exercises, improving adherence and outcomes. Integrating entertainment into therapy can motivate children, enhancing their physical and psychological well-being. Recently, a few studies revealed an improvement in vaso-occlusive episodes (VOE) after VR treatment (Agrawal et al., 2019). However, efficacy studies are needed to assess VR's potential benefits. Additionally, data regarding VR's efficacy on daily pain, functional mobility, and HRQOL as complementary therapy are limited

1. To investigate the effect of VR in reducing daily pain in children with SCD
2. To evaluate the impact of VR on improving functional mobility in children with SCD.
3. To examine the changes in PedsQL in children with SCD after engaging in VR experiences.
4. To evaluate the safety and satisfaction of fully immersive VR therapy in children with

Inclusion Criteria:

1. Children aged between 8 and 13 years.
2. Diagnosed with sickle cell disease (SCD), including homozygous SCA and other clinically confirmed variants.
3. Medically stable and cleared by the treating physician to participate in mild activity.
4. Receiving hydroxyurea as part of routine care.
5. Able to follow simple instructions and communicate pain levels.
6. Parental/legal guardian consent and child assent obtained.

Exclusion Criteria:

1. Presentence of developmental, neurological, or genetic disorders.
2. History of hip replacement or major orthopedic conditions affecting mobility.
3. Current acute chest syndrome or unstable clinical condition.
4. Visual or hearing impairments that would interfere with VR use.
5. Participation in concurrent physiotherapy or rehabilitation programs.
6. Previously enrolled in phase one of the current study (if applicable)

De-identified IPD including pain scores and outcome measures will be available upon reasonable request with appropriate ethical approval.

De-identified individual participant data (IPD), including pain scores and functional outcomes, will be made available upon reasonable request. Supporting documents such as the study protocol, statistical analysis plan, clinical study report, and analytic code will also be provided. Data will be shared through institutional data-sharing agreements and with approval from the responsible ethics committee. Availability is expected within 6 months following publication.

Individual participant data (IPD) and supporting documents will be made available beginning 6 months after publication of the main findings. Data will remain accessible for up to 3 years following the date of publication.

Qualified researchers affiliated with academic institutions or healthcare organizations may request access to de-identified IPD and supporting documents (study protocol, SAP, CSR, and analytic code). Requests must include a data use agreement and be reviewed and approved by the institutional ethics committee. Approved data will be shared securely via institutional platforms or encrypted file transfer.

No additional parties were masked beyond the outcomes assessor. Only the assessor responsible for measuring clinical outcomes was blinded to group allocation.