Inclusion Criteria:  Adult (≥18 years) male or non-pregnant, non-lactating female  Primary antibody deficiency syndrome or Secondary antibody deficiency syndrome, defined by one of the following:  IgG < 4 g/l Ongoing substitution of immunoglobline for hypogammaglobinemia Anti-CD20 antibody (monospecific) therapy for malignant disease: after combined Anti-CD20 antibody therapy with chemotherapy (e.g. fludarabin, cyclophosphamid, bendamustin, anthracycline, vincristin) or BTK-inhibitors or BCL2-inhibitors (within 1-6 months post therapy) ongoing single agent Anti-CD20 antibody therapy Anti-CD20 antibody maintenance therapy Ability to understand and voluntarily sign an informed consent form Ability to adhere to the study visit schedule and other protocol requirements Female patients of child bearing potential (FCBP) and male patients with partners of child bearing potential, who are sexually active, must agree to the use of two effective forms (at least one highly effective method) of contraception. This should be started from the signing of the informed consent and continue until three months after vaccination. Furthermore, contraception must be carried on by patients receiving B-cell depleting therapies for the whole duration of the treatment.  Postmenopausal or evidence of non-child-bearing status. For women of childbearing potential: negative urine or serum pregnancy test within 7 days prior to study treatment. Postmenopausal or evidence of nonchildbearing status is defined as:  Amenorrhoea for 1 year or more following cessation of exogenous hormonal treatments Luteinizing hormone (LH) and Follicle stimulating hormone (FSH) levels in the postmenopausal range for women under 50  Exclusion Criteria:  Pregnant or lactating females Participation in any clinical trial with intake of any nonregistered vaccine product  Any concomitant disease affecting the effect of the therapeutic vaccine or interfering with the study primary endpoint:  Active infection Psychiatric disorders Known systemic anaphylaxis Prior or current infection with SARS-CoV-2 as assessed by medical history and/or by throat/nose swab (PCR) or serologically documented immunization against SARSCoV- 2 (after infection or vaccination) Persisting symptoms developed after SARS-CoV-2 vaccination with an approved vaccine product at study inclusion History of Guillain-Barré syndrome HIV infection, chronic or active hepatitis B or C History of relevant CNS pathology or current relevant CNS pathology (e.g. seizure, paresis, aphasia, cerebrovascular ischemia/haemorrhage, severe brain injuries, dementia, Parkinson's disease, cerebellar disease, organic brain syndrome, psychosis, coordination or movement disorder, excluding febrile seizures as child) Baseline laboratory CD4+ T cell count < 100 μl  The following pre-existing medical conditions:  Chronic liver failure defined as Child-Pugh Score ≥B Chronic renal failure defined as GFR <40 ml/min/1,73m2 Serious pre-existing cardiovascular disease such as NYHA ≥ III Sickle cell anemia Patients presenting with any clinical, laboratory or radiological signs of tumor-progression Patient receiving active treatment with small molecules, including Tyrosine Kinases-Inhibitors (e.g. Ibrutinib), Proteosome-Inhibitors (e.g. Bortezomib), Bcl-2- Inhibitors (e.g. Venetoclax), Phosphoinositid-3-Kinase- Inhibors (e.g. Idelalisib) Known hypersensitivity to any of the components included in the CoVac-1 vaccine Pre-existing auto-immune disease except for Hashimoto thyroiditis and mild (not requiring immunosuppressive treatment) psoriasis Intention of receiving one dose of an already approved vaccine against SARS-CoV-2 before day 56