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Microbes & Immunity

REVIEW ARTICLE
Comparison of immune response parameters

between homologous and heterologous
COVID-19 vaccines: A scoping review

Samantha Si Mei Khoo , Kang Wei Tan , Ashwini Mahendran ,
Saatheeyavaane Bhuvanendran , and Ammu Kutty Radhakrishnan*
Food As Medicine Research Strength, Jeffery Cheah School of Medicine and Health Sciences,
Monash University Malaysia, Subang Jaya, Selangor, Malaysia

Abstract

It has been over 4 years since the emergence of the coronavirus disease
2019 (COVID-19) pandemic. This highly contagious respiratory infection has
endangered the health of millions and significantly impacted healthcare systems
and economies. Vaccines are believed to confer immunity against severe acute
respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19,
reducing both the severity of infection and the spread of the virus. Within a short
*Corresponding author: period, various COVID-19 vaccines were developed and extensively tested before
Ammu Kutty Radhakrishnan being approved by the WHO for distribution and administration. Now, due to
(ammu.radhakrishnan@monash.
edu) concerns about emerging new strains of the virus and limited vaccine availability,
a heterologous vaccine strategy is being deployed. Therefore, this paper aims to
Citation: Khoo SSM, Tan KW,
Mahendran A, Bhuvanendran S, conduct a scoping review of existing evidence to compare the immunogenicity of
Radhakrishnan AK. Comparison heterologous vaccines with homologous vaccines and determine which confers
of immune response parameters better immunity against COVID-19. A literature search was conducted across three
between homologous and
heterologous COVID-19 electronic databases (Ovid MEDLINE, PubMed, and Scopus). The retrieved studies
vaccines: A scoping review. were screened for relevance and eligibility using the online platform Covidence.
Microbes & Immunity. A total of 31 articles were shortlisted for data extraction and analysis. Among these,
2024;1(2):12-28.
doi: 10.36922/mi.3757 21 were observational studies, and 10 were clinical trials. The analysis demonstrated
that participants who received heterologous vaccination regimens generated
Received: May 24, 2024
higher levels of IgG antibodies against the spike protein of SARS-CoV-2, antibodies
Accepted: June 24, 2024 targeting the receptor-binding domain, and T-cell responses compared to those
Published Online: October 16, who received homologous vaccination regimens. Furthermore, heterologous
2024 vaccination produced higher titers of neutralizing antibodies against several
Copyright: © 2024 Author(s). variants of concern (VOC), including Alpha, Beta, Gamma, Delta, and Omicron.
This is an Open-Access article No severe vaccine-related adverse events were reported in these studies, and
distributed under the terms of the
Creative Commons Attribution common local and systemic side effects were manageable. Overall, heterologous
License, permitting distribution, vaccination regimes induced strong humoral and cellular immunity, comparable
and reproduction in any medium, to homologous vaccination regimes, with stronger neutralizing antibody activity
provided the original work is
properly cited. against VOCs.
Publisher’s Note: AccScience
Publishing remains neutral with Keywords: COVID-19; SARS-CoV-2; Heterologous vaccines; Homologous vaccines;
regard to jurisdictional claims in
published maps and institutional Immunogenicity
affiliations.

Volume 1 Issue 2 (2024) 12 doi: 10.36922/mi.3757