Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Clinical Trial
. 2024 Aug 16;230(2):e287-e291.
doi: 10.1093/infdis/jiad525.

Variant-Specific IgA Protects Against Omicron Infection

Yun Shan Goh  1 , Siew-Wai Fong  1 , Pei Xiang Hor  1 , Chiew Yee Loh  1 , Bei Wang  2 , Siti Nazihah Mohd Salleh  2 , Eve Zi Xian Ngoh  2 , Raphael Tze Chuen Lee  3   4 , Xuan Ying Poh  5 , Suma Rao  5   6 , Po Ying Chia  5   6   7 , Sean W X Ong  5   6 , Tau Hong Lee  5   6 , Clarissa Lim  5 , Jefanie Teo  5 , Surinder Pada  8 , Louisa Jin Sun  9 , Desmond Luan Seng Ong  10 , Jyoti Somani  11 , Eng Sing Lee  7   12 , Sebastian Maurer-Stroh  1   3   4   13   14   15 , Cheng-I Wang  2 , Yee-Sin Leo  5   6   7   16   17 , David C Lye  5   6   7   15 , Barnaby Edward Young  5   6   7 , Lisa F P Ng  1   18   19 , Laurent Renia  1   7   20 ; NCID Study Group; COVID-19 Cohort Study Group
Collaborators, Affiliations
Clinical Trial

Variant-Specific IgA Protects Against Omicron Infection

Yun Shan Goh et al. J Infect Dis. .

Abstract

Background: The emergence of rapidly evolving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, coupled with waning vaccine-induced immunity, has contributed to the rise of vaccine breakthrough infections. It is crucial to understand how vaccine-induced protection is mediated.

Methods: We examined 2 prospective cohorts of mRNA vaccinated and boosted individuals during the Omicron wave of infection in Singapore.

Results: We found that individuals who remain uninfected over the follow-up period had a higher variant-specific IgA, but not IgG, antibody response at 1 month after booster vaccination, compared with individuals who became infected.

Conclusions: We conclude that IgA may have a potential contributory role in protection against Omicron infection. Clinical Trials Registration . NCT05142319.

Keywords: COVID-19; IgA; Omicron; S protein; SARS-CoV-2; antibodies; mRNA vaccine.

PubMed Disclaimer

Conflict of interest statement

Potential conflicts of interest. A patent application for the spike protein flow cytometry-based assay has been filed (Singapore patent No. 10202009679P: A Method of Detecting Antibodies and Related Products) by Y. S. G., L. R., and L. F. P. N. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.

Figures

Figure 1.
Figure 1.
Specific responses against wild-type (WT) and Omicron BA1 spike at 1 month after booster vaccination in the SCOPE cohort (n = 55). No individuals were infected prior to booster vaccination. By 8 months after booster vaccination, 26 individuals were infected (indicated by +) while 29 individuals remained uninfected (indicated by −). Plasma immunoglobulin G (IgG) and IgA against WT and Omicron BA1 spike responses at 1 month after booster vaccination were analyzed by the spike protein flow cytometry-based assay. Bar represents the median value. Comparisons between groups were performed using Mann-Whitney test. Only significant comparison is indicated in the figure, as marked by the bracket and the numerical P-value of the comparison.
Figure 2.
Figure 2.
Specific responses against WT and Omicron BA1 spike at 1 month after booster vaccination in the PRIBVAC Phase A cohort (n = 93). No individuals were infected prior to booster vaccination. By 12 months after booster vaccination, 66 individuals were infected (indicated by +) while 27 individuals remained uninfected (indicated by −). Plasma immunoglobulin G (IgG) and IgA against WT and Omicron BA1 spike responses before booster vaccination were analyzed by the spike protein flow cytometry-based assay. Bar represents the median value. Comparisons between groups were performed using Mann-Whitney test. Only significant comparison is indicated in the figure, as marked by the bracket and the numerical P-value of the comparison.
See this image and copyright information in PMC

References

    1. McDonald I, Murray SM, Reynolds CJ, Altmann DM, Boyton RJ. Comparative systematic review and meta-analysis of reactogenicity, immunogenicity and efficacy of vaccines against SARS-CoV-2. NPJ Vaccines 2021; 6:74. - PMC - PubMed
    1. Earle KA, Ambrosino DM, Fiore-Gartland A, et al. . Evidence for antibody as a protective correlate for COVID-19 vaccines. Vaccine 2021; 39:4423–8. - PMC - PubMed
    1. Khoury DS, Cromer D, Reynaldi A, et al. . Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection. Nat Med 2021; 27:1205–11. - PubMed
    1. Aldridge RW, Yavlinsky A, Nguyen V, et al. . SARS-CoV-2 antibodies and breakthrough infections in the virus watch cohort. Nat Commun 2022; 13:4869. - PMC - PubMed
    1. Bergwerk M, Gonen T, Lustig Y, et al. . COVID-19 breakthrough infections in vaccinated health care workers. N Engl J Med 2021; 385:1474–84. - PMC - PubMed

Publication types

Supplementary concepts

Associated data