Hybrid immunity from bivalent vaccination and prior infection enhances humoral and innate protection against Omicron XBB.1.16 and EG.5.1.1 variants in Japan - Scorecard - MDSpire
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Enhanced Humoral and Innate Immunity Against Omicron Variants XBB.1.16 and EG.5.1.1 in Japan Through Hybrid Immunity from Bivalent Vaccination and Previous Infection

  • By

  • Kouki Matsuda

  • Shohei Yamamoto

  • Chihiro Motozono

  • Yoshiki Aritsu

  • Yuki Furukawa

  • Airi Noborio

  • Daisuke Takada

  • Hiyori Sasagawa

  • Yuichi Akahori

  • Kiyoto Tsuchiya

  • Hiroyuki Gatanaga

  • Takamasa Ueno

  • Norio Ohmagari

  • Tetsuya Mizoue

  • Kenji Maeda

  • July 2, 2026

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Clinical Scorecard: Enhanced Humoral and Innate Immunity Against Omicron Variants XBB.1.16 and EG.5.1.1 in Japan Through Hybrid Immunity from Bivalent Vaccination and Previous Infection

At a Glance

CategoryDetail
ConditionCOVID-19
Key MechanismsHybrid immunity enhances neutralizing activity and innate immune responses.
Target PopulationAdults with ≥3 mRNA vaccine doses in Japan.
Care SettingImmunological assessment in a serological survey.

Key Highlights

  • Hybrid immunity yields higher neutralization titers compared to vaccine-only groups.
  • Breakthrough infections are more common in individuals with low-vaccine-induced immunity.
  • Elevated IL-8 levels are associated with hybrid immunity and macrophage-neutrophil interactions.

Guideline-Based Recommendations

Diagnosis

  • Prior SARS-CoV-2 infection defined by PCR confirmation or seropositivity for N-IgG.

Management

  • Consider hybrid immunity in evaluating breakthrough infection risks.

Monitoring & Follow-up

  • Monitor neutralizing antibody titers and cytokine profiles in vaccinated individuals.

Risks

  • Breakthrough infections remain common despite vaccination, particularly with immune-evasive variants.

Patient & Prescribing Data

Adults with a history of vaccination and potential prior infection.

Bivalent mRNA vaccines may enhance hybrid immunity against emerging variants.

Clinical Best Practices

  • Encourage vaccination and monitor for breakthrough infections.
  • Assess both humoral and innate immune responses in vaccinated populations.

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