ArticleInfluenza and other respiratory viruses2026
Impact of First SARS-CoV-2 Infection Variant on Serological Responses Against Omicron: Findings From the SIREN Study.
Article in Influenza and other respiratory viruses, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
2 citing papers in PubMed.
- SARS-CoV-2 Omicron infection reveals imprinted antibody responses in the absence of vaccination.iScience · 2026Article
- Impact of First SARS-CoV-2 Infection Variant on Serological Responses Against Omicron: Findings From the SIREN Study.Influenza and other respiratory viruses · 2026Article
Corrections and comments
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Authors and funding
13 authors.
Funding
Abstract
introductionDespite the existing hybrid immunity, a sharp increase in SARS-CoV-2 reinfections was observed worldwide following Omicron variant emergence. We investigated whether the first infecting variant indelibly shapes serological responses against Omicron (BA.1 and BA.2) reinfection.
methodsParticipants with a sequence-confirmed Alpha (n = 23) or Delta (n = 10) first infection before third vaccine dose (V3) that subsequently had a BA.1 or BA.2 reinfection were selected. Sera were tested for anti-SARS-CoV-2 spike (anti-S) and live virus microneutralisation (LV-N) against Ancestral, Alpha, Delta, Omicron BA.1 and BA.2. Antibody responses and waning post-V3 were compared by first infection variant using mixed-effect models, as well as inferred titres days before reinfections. Individual's neutralisation responses were compared 12 weeks post-V3, among those with Alpha and Delta primary infection.
resultsAfter V3, those with Delta first infection had higher LV-N Omicron BA.1 titres (fold difference (FD) = 2.7, p = 0.05) compared to Alpha primary infection. Participants with Delta first infection presented higher LV-N BA.1 (FD = 1.89, p = 0.004) and LV-N BA.2 (FD = 2.06, p = 0.001) titres pre-Omicron reinfections. Individuals' neutralisation responses against Ancestral were higher than any other subsequent variants, regardless of first infection variant.
conclusionsA previous Delta SARS-CoV-2 infection induced a higher serological response against a subsequent Omicron infection when compared to Alpha first infections.
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