Observational Study
Copyright ©The Author(s) 2025. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Virol. Jun 25, 2025; 14(2): 99663
Published online Jun 25, 2025. doi: 10.5501/wjv.v14.i2.99663
Risk of COVID-19 infection among frontline healthcare workers during the COVID-19 pandemic
Kundavaram Paul Prabhakar Abhilash, Mathew Varghese Nellimootil, Binila Chacko, Darpanarayan Hazra, Victor Coelho, John Emmanuel Jesudasan, Karthik Gunasekaran, Lovely Thomas, More Atul Ramchandra, Jonathan Melchizedek, Henah Meshack Gunaraj, Mahesh Moorthy, John Victor Peter
Kundavaram Paul Prabhakar Abhilash, Darpanarayan Hazra, John Emmanuel Jesudasan, Department of Emergency Medicine, Christian Medical College Vellore, Vellore 632004, Tamil Nādu, India
Mathew Varghese Nellimootil, Department of Respiratory Medicine, Christian Medical College Vellore, Vellore 632004, Tamil Nādu, India
Binila Chacko, Lovely Thomas, More Atul Ramchandra, Jonathan Melchizedek, Henah Meshack Gunaraj, John Victor Peter, Department of Medical Intensive Care, Christian Medical College Vellore, Vellore 632004, Tamil Nādu, India
Victor Coelho, Department of General Surgery, Christian Medical College Vellore, Vellore 632004, Tamil Nādu, India
Karthik Gunasekaran, Department of Medicine, Christian Medical College Vellore, Vellore 632004, Tamil Nādu, India
Mahesh Moorthy, Department of Clinical Virology, Christian Medical College Vellore, Vellore 632004, Tamil Nādu, India
Co-first authors: Kundavaram Paul Prabhakar Abhilash and Mathew Varghese Nellimootil.
Co-corresponding authors: Mahesh Moorthy and John Victor Peter.
Author contributions: Abhilash KPP, Chacko B and Peter JV were responsible for study design; Abhilash KPP, Nellimootil MV, Chacko B, Hazra D, Coelho V, Jesudasan JE, Gunasekaran K, Thomas L, Ramchandra MA, Melchizedek J, Gunaraj HM were responsible for conduct of the study, and data collection; Abhilash KPP, Nellimootil MV, Chacko B, Moorthy M, and Peter JV were responsible for data analysis; Moorthy M was responsible for laboratory aspects; Abhilash KPP, Nellimootil MV, Chacko B, Hazra D, Coelho V, Jesudasan JE, Gunasekaran K, Thomas L, Ramchandra MA, Melchizedek J, Gunaraj HM, Moorthy M, and Peter JV were responsible for literature review and final approval of the manuscript; all of the authors read and approved the final version of the manuscript to be published.
Supported by Internal Institutional Research Fund.
Institutional review board statement: The study was approved by the Institutional Review Board and Ethics Committee (No. 12751, dated 1 May, 2020).
Informed consent statement: All study participants provided written consent before study enrollment.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: There is no additional data available.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: John Victor Peter, MD, DNB, FRACP, FJFICM, FCICM, FICCM, FRCPE, FAMS, M. Phil, Professor, Department of Medical Intensive Care, Christian Medical College Vellore, Ida Scudder Road, Vellore 632004, Tamil Nādu, India. peterjohnvictor@yahoo.com.au
Received: July 27, 2024
Revised: November 7, 2024
Accepted: November 26, 2024
Published online: June 25, 2025
Processing time: 331 Days and 1.4 Hours
Abstract
BACKGROUND

In the initial stages of the coronavirus disease 2019 (COVID-19) pandemic, healthcare workers (HCWs) who were immunologically naive to COVID-19, were exposed to a highly transmissible virus.

AIM

To compare infection risk among HCWs in high-risk (HR) and low-risk (LR) areas.

METHODS

Data on reverse transcriptase-polymerase chain reaction confirmed clinical infection and samples for nucleocapsid, and spike protein antibodies were collected at five time-points (T1 to T5) from HCWs in the emergency department and intensive care unit (HR group) and pre-clinical and para-clinical areas (LR). For the sero-study, only participants who provided at least one baseline sample and one during the second wave (T4 or T5) were analysed. Since CovishieldTM elicits only spike protein antibodies, subclinical infection was diagnosed if asymptomatic unvaccinated and CovishieldTM vaccinated individuals tested positive for nucleocapsid antibody.

RESULTS

Overall, by T5, clinical infection rate was similar in the HR (120/366, 32.8%) and LR (22/82, 26.8%) groups (P = 0.17). However, before vaccination (T3), more HCWs in the HR group developed COVID-19 infection (21.9% vs 8.8%, P = 0.046). In the sero-study group, clinical infection occurred in 31.5% (45/143) and 23.7% (14/59) in the HR and LR groups respectively (P = 0.23). Spike antibody was detected in 140/143 (97.9%) and 56/59 (94.9%) and nucleocapsid antibody was positive in 95/143 (66.4%) and 35/59 (59.3%) in the HR and LR groups respectively (P = 0.34). Subclinical infection rate (HR 34.9%, LR 35.6%, P = 0.37) and hospitalization rate were similar. There was no mortality.

CONCLUSION

Before vaccination, HCWs in HR areas had a higher risk of infection. Seroprevalence studies suggest that sub-clinical infection was not uncommon.

Keywords: COVID-19 pandemic; Seroprevalence; Healthcare workers; SARS-CoV-2 antibodies; Nucleocapsid antibody; Spike protein antibody

Core Tip: This study tracked clinical infection and seroprevalence to severe acute respiratory syndrome-coronavirus 2 virus during the two waves of the pandemic in India and compared infection risk between health care workers (HCWs) in high-risk (HR) areas (emergency department, critical care) and low-risk (LR) non-clinical areas. The seroprevalence rate of 1.1% at the start of the pandemic increased to 34.1% and 60.1% during the first and second waves respectively. Prior to vaccination, more HCWs in HR areas developed clinical infection. Following vaccination, clinical infection rates and seropositivity were similar in HR and LR groups. About 1/3rd had evidence of subclinical infection.