Comparison of safety and immunogenicity in the elderly after receiving either Comirnaty or Spikevax monovalent XBB1.5 COVID-19 vaccine

J Infect. 2025 Jan;90(1):106374. doi: 10.1016/j.jinf.2024.106374. Epub 2024 Dec 8.

Abstract

Background: The emergence of SARS-CoV-2 variants necessitates ongoing evaluation of vaccine performance. This study evaluates and compares the safety and immunogenicity of the Comirnaty and Spikevax monovalent XBB.1.5 COVID-19 vaccines in an elderly population.

Methods: Altogether, 129 elderly individuals were recruited between 2 January and 3 February 2024, and received a booster dose of either Comirnaty (n=59) or Spikevax (n=70) monovalent XBB.1.5 COVID-19 vaccine. Blood samples were collected at before and one month after vaccination. Immunogenicity was assessed by measuring the percentage of IFNγ+CD4+ and IFNγ+CD8+ T cells, and neutralizing antibody titers (NT50) using a surrogate virus neutralization test (sVNT). Adverse reactions were recorded and analyzed.

Findings: Both vaccines significantly increased the percentage of IFNγ+CD8+ T cells against XBB.1.5 and wild-type (WT) SARS-CoV-2 at one-month post-vaccination. Spikevax induced a significantly higher percentages of IFNγ+CD8+ and CD4+ T cells against XBB.1.5 than Comirnaty (p<0.001). The proportion of participants showing a positive T cell response to XBB1.5 after vaccination was higher in the Spikevax group (64.3% CD8, 71.4% CD4) than in the Comirnaty group (42.4% CD8, 57.6% CD4). Spikevax also elicited higher NT50 levels against XBB1.5, JN.1 and the latest variant KP.2 than Comirnaty (XBB1.5: p<0.01; KP.2: p<0.05). Fever was more common in the Spikevax group (fever: p=0.006). However, all side effects were short-term and resolved on their own.

Interpretation: Both vaccines induce neutralizing antibody to XBB1.5, JN.1 and KP.2. Specifically, Spikevax induces higher cellular and humoral immune responses than Comirnaty in the elderly, but it is also associated with a higher incidence of fever. These findings can guide public health strategies for vaccinating the elderly population.

Keywords: JN.1 variant; KP.2 variant; Neutralizing antibodies; Omicron XBB variant; T-cell immunity; XBB.1.5 vaccines.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Antibodies, Neutralizing* / blood
  • Antibodies, Viral* / blood
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes* / immunology
  • COVID-19 Vaccines* / administration & dosage
  • COVID-19 Vaccines* / adverse effects
  • COVID-19 Vaccines* / immunology
  • COVID-19* / immunology
  • COVID-19* / prevention & control
  • Female
  • Humans
  • Immunization, Secondary
  • Immunogenicity, Vaccine*
  • Interferon-gamma / immunology
  • Male
  • SARS-CoV-2
  • Vaccination

Substances

  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COVID-19 Vaccines
  • Interferon-gamma

Supplementary concepts

  • SARS-CoV-2 variants