The aim of this study is to identify adverse events following vaccination by the COVID-19 vaccine by evaluating adverse side effects, hematological values; immunogenicity in the Egyptian candidates in response to COVID-19 vaccine, summarizing the which may occur following administration of COVID-19 vaccine.

Coronavirus disease 2019 (COVID-19) is an emerging respiratory infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that had infected more than 100 million individuals and caused more than 2 million deaths worldwide by February 13, 2021. A safe and effective vaccination trials against COVID-19 is urgently needed. There are currently more than 160 COVID-19 candidate vaccines in development worldwide, and 25 are in different phases of clinical trials using different platforms.

The efficacy and immunogenicity of vaccines varies depending on the study cohort. Race and ethnicity were shown to affect the antibody responses to the rubella vaccine, which elicited significantly higher titers in children of African ethnicity compared to those of European descent or Hispanic ethnicity, likely, disparities in serologic responses to vaccines were also observed between different ethnic groups for the Haemophilus influenzae type b-tetanus toxoid conjugate vaccine , or the Haemophilus influenzae type b polysaccharide-Neisseria meningitidis outer membrane protein conjugate vaccine . thus keeping the race an important factor in studding its effect on immunogenicity of vaccine. Thus keeping the race an important factor in studding its effect on immunogenicity of vaccine, which pushed us to estimate immunogenicity in Egyptian population after vaccination with the inactivated COVID-19 vaccine.

Heamatological changes after vaccination had been detected in many researches; lecuocytosis was found shortly after vaccination of infants, which was primarily a neutrophilia but no participant received antibiotics and all remained well at follow-up . In a case series study, also leukocytosis with fever was detected following pneumococcal vaccine administration . On the other hand, neutropenia was detected following a new vaccine against Shigella sonnei . Platelets abnormalities also had been detected following vaccination, a previous example is idiopathic thrombocytopenic purpura, linked to the administration of measles-containing vaccines .

Inclusion Criteria:

1. People aged 18-80 years.
2. Negative for serum-specific IgM/IgG antibodies against SARS-CoV-2, as measured by a commercial kit (Innovita, China) at the time of screening.

Exclusion Criteria:

1. A history of infection with SARS-CoV 3 months before the vaccine.
2. Fever, cough, runny nose, sore throat, diarrhoea, dyspnoea, or tachypnoea in the 14 days before vaccination.
3. Pregnancy.
4. A history of seizures or mental illness.
5. Being on immunosuppressive agents.
6. Being on anticoagulation therapy.
7. Being unable to comply with the study schedule.

HCWs in Assiut University Hospitals accepted to take vaccine