Immunological Response to Conventional COVID-19 Vaccines in a Cohort of Pakistani Healthy Recipients
Preventive Medicine Department, King Abdulaziz University Hospital, King Abdulaziz University, Jeddah 22252, 1Community Medicine Department, King Abdulaziz University, Jeddah 21589, Saudi Arabia, 2Institute of Pathology and Diagnostic Medicine, Khyber Medical University Khyber Pakhtunkhwa 25100, 3Department of Pathology, Khyber Girls Medical College, Hayatabad, Peshawar 59000, Pakistan, 4Department of Medical Microbiology and Parasitology, Faculty of Medicine, 5Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, 6Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, 7Special Infectious Agents Unit-Biosafety Level-3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21362, 8Family and Community Medicine Department, Faculty of Medicine in Rabigh, 9King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia, 10Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
Y. M. Yousafza, Institute of Pathology and Diagnostic Medicine, Khyber Medical University Khyber Pakhtunkhwa 25100, Pakistan, E-mail: email@example.com
Coronavirus disease 2019 mass vaccination has led to drastic reduction in hospitalizations and mortality. A number of case reports have emerged reporting coronavirus disease 2019 infection within days following vaccination. There is a need to understand development of immune antibodies in the early post-vaccination period. A prospective analysis of immunoglobulin M and immunoglobulin G kinetics was conducted during the first 28 d following vaccination with either CanSino or Sinovac vaccines in a cohort of 40 healthy volunteers. Serial blood samples were collected from the volunteers right before the first dose of vaccine (d 0) and then on d 4, d 7, d 14, d 21, d 24 and d 28 post-vaccination. Using enzyme-linked immunosorbent assay, circulating anti-severe acute respiratory syndrome coronavirus 2 receptor binding domain immunoglobulin M and immunoglobulin G antibodies were analyzed. Most vaccine recipients (31/40) did not develop any circulating immunoglobulin M. The remaining 9 recipients showed a typical immunoglobulin M curve with antibodies appearing on d 4, peaking on d 7 and declining on d 21 and beyond. Immunoglobulin G response was more typical within 38/40 recipients showing the appearance of immunoglobulin G on d 4, which continued till the end of the study period. This study demonstrates that vaccine-induced immunoglobulin M-based immunity cannot be relied during the first few days following vaccination and more time is needed to have a better picture of the real situation.