Waning of Antibody Response Among Vaccinees who Received Two Doses of Covishield Vaccine

Shivani Haritay; Rithia Patil; Arif Maldar; Anil Kumar; Vikrama Reddy; Deshna Oswal; Masood Ahmed Tahashildar; Akshay Kolakar; Satish Kabbur; Jang Bahadur Prasad; M S Shivaswamy; Ramesh Paranjape; Mubashir Angolkar

doi:10.4103/jgid.jgid_128_22

Waning of Antibody Response Among Vaccinees who Received Two Doses of Covishield Vaccine

J Glob Infect Dis. 2023 Feb 28;15(1):19-22. doi: 10.4103/jgid.jgid_128_22. eCollection 2023 Jan-Mar.

Affiliations

¹ Department of Public Health, KLE Academy of Higher Education and Research, Belgaum, Karnataka, India.
² Dr. Prabhakar Kore BSRC, KLE Academy of Higher Education and Research, Belgaum, Karnataka, India.
³ J. N. Medical College, KLE Dr. Prabhakar Kore Charitable Hospital, Belgaum, Karnataka, India.
⁴ Department of Biostatistics, KLE Academy of Higher Education and Research, Belgaum, Karnataka, India.
⁵ Department of Community Medicine, J. N. Medical College, KLE Academy of Higher Education and Research, Belgaum, Karnataka, India.

Abstract

Introduction: There are limited data available on the long-term presence of SARS-CoV-2-specific binding antibodies and neutralizing antibodies in circulation among the elderly population. This study aims to examine levels of anti-SARS-CoV-2 antibodies in vaccines who have completed at least 6 months since the second vaccine dose. A cross-sectional study was conducted from November 2021 to January 2022 among 199 vaccines aged 60 years and above residing in Belagavi city, who received two doses of the Covishield vaccine.

Methods: Antibody response to SARS-COV-2 virus whole cell antigen was measured by a kit COVID KAWACH IgG Micro LISA (J Mitra and Company, India) in 199 participants who had completed at least 6 months after receiving the second dose of Covishield vaccine. The antibody response was measured as a ratio of optical density (OD) in the participant's sample to the mean OD in negative control test by normal (T/N). Independent Kruskal-Wallis test was applied to test the difference between the T/N ratio by months of vaccination since the second dose and by the age group strata.

Results: The median T/N values among participants who completed 6, 7, 8, and 9 months since the second vaccine dose were 14.17, 10.46, 7.93, and 5.11, respectively, and this decline in T/N values was statistically significant. Antibody response values showed a decline with increasing age for participants in the age strata 60-69, 70-79, and 80 and above, respectively.

Conclusions: A significant decline was observed in antibody response over 9 months supporting the administration of booster dose of vaccine.

Keywords: Antibody waning; COVID-19 vaccine; SARS-CoV-2; booster dose; elderly population; immunoglobulin G antibodies.