Inactivated SARS-COV-2 Vaccine: Sinopharm Pak Armed Forces Med J 2021; 71 (6): 2024 IMMUNOGENICITY AND SAFETY OF INACTIVATED SARS-COV-2 VACCINE (VERO CELL), BBIBP-CORV (SINOPHARM); AN OBSERVATIONAL STUDY FROM PAKISTAN Muhammad Farooq, Muhammad Fayyaz Malik, Ashfaq Hussain, Majid Latif, Muhammad Usman Rathore, Rehan Ahmad Khan Lodhi Combined Military Hospital Sialkot/National University of Medical Sciences (NUMS) Pakistan ABSTRACT Objective: To ascertain the immunogenicity and short-term safety of inactivated SARS-CoV-2 Vaccine (Vero Cell), BBIBP- CorV (Sinopharm) in our setup. Study Design: Cross-sectional study. Place and Duration of Study: Combined Military Hospital Sialkot Pakistan, from Feb to Apr 2021. Methodology: A total of 227 health care workers (HCWs) between 18 to 59 years of age were included in the study. Two doses of Inactivated SARS-CoV-2 Vaccine (Vero Cell), BBIBP-CorV were administered to all individuals 21 days apart and they were monitored for any vaccine-related adverse reactions for 7 days after each dose. Neutralizing antibodies (NAbs) in study subjects were detected in three samples i.e. before 1st dose of vaccine, 21 days after 1st dose and 14 days after 2nd dose by Elecsys Anti- SARS-CoV-2 S (Roche Diagnostics). Results: Mean age of individuals in the study was 36.70 ± 18.08 years and most individuals were in the 31-45 years age group. Fatigue and drowsiness were the most common adverse effects experienced by study subjects after 1st and 2nd dose of the vaccine followed by malaise and headache. Only 42 (39%) individuals developed positive neutralizing antibody titers in a sample taken 21 days after 1st dose while all individuals except one (99%) developed positive neutralizing antibody titers in a sample taken 2 weeks after 2nd vaccine dose. Conclusion: Inactivated SARS-CoV-2 Vaccine (Vero Cell), BBIBP-CorV is safe and well-tolerated with very few adverse reactions. Immunogenicity was well achieved as the seroconversion rate was 99% two weeks after 2nd dose of the vaccine. Keywords: Coronavirus disease 2019 (COVID-19), Inactivated SARS-CoV-2 vaccine, Neutralizing antibodies (NAbs). How to Cite This Article: Farooq M, Malik MF, Hussain A, Latif M, Rathore MU, Lodhi RAK. Immunogenicity and Safety of Inactivated Sars-Cov-2 Vaccine (Vero Cell), Bbibp-Corv (Sinopharm); An Observational Study from Pakistan. Pak Armed Forces Med J 2021; 71(6): 2024-2028. Doi: https://doi.org/10.51253/pafmj.v6i6.7034 INTRODUCTION COVID-19 caused by severe acute respiratory syndrome- coronavirus 2 (SARS-CoV-2) was declared a pandemic on 11th March 2020 by World Health Organization (WHO). The increase in COVID-19 cases was at a shocking rate throughout the world. 1 As of 25 May 2021, the number of COVID-19 cases has reached above 166.86 million worldwide with more than 3.45 million deaths. 2 COVID-19 has caused social and econ- omic instability and it proved to be disastrous to public health placing life on hold worldwide since December 2019. 3 There is a shortage of medical necessities, hospi- tals have become overburdened, and health care wor- kers have been drained as a result of the constant fight against the pandemic. 4 Isolation, physical distancing and wearing of masks were useful in restricting the sp- read of infection in the short term. Older individuals, those with comorbid conditions and healthcare wor- kers are at significantly high risk. 5-6 The development of a vaccine is of utmost urgency and importance to curb the global pandemic and precipitously growing numbers of death. 1,4 Multi- ple vaccine types against SARS-CoV-2 are under deve- lopment which includes DNA, RNA based vaccines, recombinant vaccines, vector-based vaccines and in- activated virus vaccines. 1,7-9 Moderna and Pfizer/Bio NTech are two important RNA vaccines that encode SARS-CoV-2 spike glycoprotein, Novavax a protein subunit vaccine while vaccines of Astra Zeneca (Ox- ford University), CanSino, Janssen/Johnson & John- son and Gamaleya comprise adenovirus vector plat- forms expressing spike protein. 3,4,9-10 There are several Chinese vaccines in development while Sinovac and Sinopharm have received emergency use approval in China and various other countries. These two vaccines are comprised of the whole inactivated virus where alum (Aluminium hydroxide) is an adjuvant. 5,8,10 Sino- pharm has now announced vaccine efficacy of 79%. 10 Inactivated vaccines have extensively been used to control the spread of various infectious diseases and these types of vaccines are developed at a relatively fast speed which makes them an encouraging strategy for vaccine development against COVID-19. 7 Viruses are grown in cell culture of mammalian cells and then This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited. Correspondence: Dr Muhammad Farooq, Colsultant Microbiologist Combined Military Hospital Sialkot-Pakistan Received: 06 Jul 2021; revision received: 17 Sep 2021; accepted: 30 Sep 2021 zahid689@gmail.com Original Article Open Access