After SARS-COV-2 inactivated vaccine authorization for use in different countries including Egypt, investigating its immunogenicity, safety, and efficacy in preventing COVID-19 infection is highly needed. In Egypt, immunization of HCWs in isolation hospitals by SARS-COV-2 inactivated vaccine is now a national priority. Moreover, data and reports regarding the application of vaccine are still limited and deficient.

This study will be conducted at Zagazig University hospital. Laboratory work will be implemented at Immunology Research Laboratory at Microbiology and Immunology Department, Faculty of Medicine, Zagazig University. A representative sample will be drawn from healthcare workers (HCWs) at Zagazig University Hospital. Assessment of inclusion and exclusion criteria by history taking. Blood samples will be drawn from HCWs by direct venipuncture before the start of immunization and 14 days after immunization. The incidence of any adverse reactions after each immunization will be recorded. SARS-CoV-2 neutralizing antibodies will be detected by enzyme-linked immunosorbent assay.

Inclusion Criteria:

-Healthy healthcare workers

Exclusion Criteria:

• Healthy healthcare workers' refusal.
• Pregnancy and lactation.
• Confirmed acute cases of SARS-CoV-2 Infection
• Having a history of SARS-CoV-2 infection in the past 3 months.
• Fever (body temperature > 37.0 ℃), dry cough, fatigue, nasal obstruction, runny nose, pharyngeal pain, myalgia, diarrhea, shortness of breath and dyspnea occurred within 14 days before vaccination.
• History of allergy to any vaccines
• Previous vaccination within the last 30 days