An effective vaccine stands as the most effective way for controlling the COVID 19 pandemic , yet, immunogenic vaccine efficacy needs to be extensively studied . T cell responses against the structural proteins have been found to be the most immunogenic in peripheral blood mononuclear cells of convalescent SARS-CoV1 patients which needs to be tested in SARS -COV2 vaccine efficacy studies alongside with the sustainability of humoral and cellular immune responses . Clinically , immunocompromised patients face drastic outcome of infections , which led the Advisory Committee on Immunization Practices (ACIP) - USA -and the Joint Committee on Vaccination and Immunisation (JCVI) -UK- recommend COVID-19 vaccination of immunocompromised , the WHO Strategic Advisory Group of Experts on Immunization (SAGE), recommended that the three vaccines(Pfizer ,Moderna and Astra Zeneca) can be used for individuals with high-risk comorbidities . Nevertheless, there is an unmet research need concerning the immune response towards COVID 19 vaccination in this population .

Based on the previous work of our team in designing B and T cell epitopes distributed over the S protein , we will study the immune response in the available vaccines in Egypt.

This proposed project is a joint collaboration between the National Research Center(NRC) , Hematology treatment unit of the holding company for biological products and vaccines (VACSERA) and Theodor Bilharz research institute . After a 1 month period of preparation , enrollment will start at month 2 (M2) over a 2 months enrollment window, where persons from 18-70 years old , of both sexes , having their first vaccination dose no more than 3 weeks of any of the available vaccines in Egypt will be enrolled into the project after signing an informed consent . Healthy persons not suffering from any systemic diseases will be enrolled from Theodor Bilharz vaccination center , and the Medical Researches Center of Excellence ( MRCE) at the NRC from the NRC vaccinated staff , while splenectomised B thalassemia patients will be enrolled from the hematology treatment unit at VACSERA . First visit will be performed 3 weeks post the first vaccination dose , while the second visit will be performed 3 weeks post the second vaccination dose , and the third visit will be performed 3 months post the second vaccination dose where ( 5 ) ml of blood will be withdrawn at each visit for the determination of the primary immune response at the first 2 visits and the sustainability of the immune response at the third visit . Enrolled persons will be instructed to contact the project logistics administrator upon experiencing any suspicious symptom of COVID 19 infection ( Fever- loss of taste and/or smell - myalgia - malaise - headache - diarrhea ) who will arrange for an additional visit where a PCR test for COVID 19 will be performed for the determination of breakthrough infections , and if positive this will be considered a primary end point and an additional ( 5) ml of blood will be withdrawn for testing for the immune status .

Inclusion Criteria:

1. Both sexes.
2. 3 weeks post scheduled first vaccination dose
3. Healthy group not suffering from any systemic diseases.
4. B thalassemia major splenectomized group
5. Signing an informed consent .

Exclusion Criteria:

1- Malignancy of whatever nature. 2- Systemic diseases apart from B thalassemia for the B thalassemia group. 3- Previous infection with COVID 19 . 4- Refusal to sign the informed consent .

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The study will comprise 200 subjects divided into 2 groups; Group 1 : 100 healthy subjects not suffering of systemic diseases vaccinated at any of the MOH vaccination centers. Group 2: 100 B thalssemia splenectomised patients representing an immunocompromised cohort.

Data will be shared through published scientific papers that come out of the study , in addition to conferences presentations.

AT month 12 of the study