UMass Chan Medical School Faculty Publications

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Program in Molecular Medicine

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Immunology and Infectious Disease | Infectious Disease | Microbiology | Virus Diseases


There is increasing evidence that the risk of SARS-CoV-2 infection among vaccinated individuals is variant-specific, suggesting that protective immunity against SARS-CoV-2 may differ by variant. We enrolled vaccinated (n = 39) and unvaccinated (n = 11) individuals with acute, symptomatic SARS-CoV-2 Delta or Omicron infection and performed SARS-CoV-2 viral load quantification, whole-genome sequencing, and variant-specific antibody characterization at the time of acute illness and convalescence. Viral load at the time of infection was inversely correlated with antibody binding and neutralizing antibody responses. Increases in antibody titers and neutralizing activity occurred at convalescence in a variant-specific manner. Across all variants tested, convalescent neutralization titers in unvaccinated individuals were markedly lower than in vaccinated individuals. For individuals infected with the Delta variant, neutralizing antibody responses were weakest against BA.2, whereas infection with Omicron BA.1 variant generated a broader response against all tested variants, including BA.2.


Infectious Diseases, SARS-CoV-2, vaccine, immunity, variants, breakthrough infection

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Seaman MS, Siedner MJ, Boucau J, Lavine CL, Ghantous F, Liew MY, Mathews J, Singh A, Marino C, Regan J, Uddin R, Choudhary MC, Flynn JP, Chen G, Stuckwisch AM, Lipiner T, Kittilson A, Melberg M, Gilbert RF, Reynolds Z, Iyer SL, Chamberlin GC, Vyas TD, Vyas JM, Goldberg MB, Luban J, Li JZ, Barczak AK, Lemieux JE. Vaccine Breakthrough Infection with the SARS-CoV-2 Delta or Omicron (BA.1) Variant Leads to Distinct Profiles of Neutralizing Antibody Responses. medRxiv [Preprint]. 2022 Mar 3:2022.03.02.22271731. doi: 10.1101/2022.03.02.22271731. PMID: 35262094; PMCID: PMC8902886. Link to preprint on medRxiv.


This article is a preprint. Preprints are preliminary reports of work that have not been certified by peer review.

Full author list omitted for brevity. For the full list of authors, see article.

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Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.