This study will assess the relative safety, tolerability, and participant satisfaction in participants using the rapid manual push method with Cutaquig®. The hypothesis being that treatment with Cutaquig® by rapid manual push method will improve the safety, tolerability and patient satisfaction of participants with PID or SID.

Cutaquig® by rapid push is already approved in Canada and has proven to be efficacious in preventing significant infection. However, relative safety, tolerability, and patient satisfaction have not been studied in these patients. The information gained from this study will improve the safety and tolerability knowledge database and will support the optimal use of Cutaquig® - thus benefitting both physicians and patients.

Primary and secondary immunodeficiency diseases (PID and SID, respectively) affect the development and/or function of the immune system, resulting in increased frequency of infection. Treatment of these disorders using Cutaquig® (a subcutaneous immunoglobulin infusion (SCIG)) was licensed in Canada in 2018 and has proven to be effective in preventing significant infection. Other brands of SCIG can be given by the participant using a syringe (called rapid manual push method), which shows the same efficacy as administration by a programmable pump. The rapid manual push method has the potential to improve quality of life, reduce infusion time, and reduce the cost of administration. This study will evaluate the safety, tolerability, and patient satisfaction of Cutaquig® by the rapid manual push method in participants with PID or SID. It will also compare the efficacy of Cutaquig with prior SCIG treatment, if applicable, in participants with PID or SID.

Inclusion Criteria:

• Adult patients (≥ 18 years)
• Who have PID or SID requiring IgG replacement therapy
• For whom the investigator decides to maintain immunoglobulin replacement therapy with subcutaneous injections of Cutaquig® 165 mg/mL at home
• Having signed an informed consent form

Exclusion Criteria:

-Patients currently participating in another interventional study at the time of inclusion

This study will observe approximately 30 adult patients with PID or SID requiring IgG replacement therapy, regardless of gender or treatment regimen. Patients will be enrolled from about 2-5 centres in Canada.