Vaccine-Associated Enhanced Disease and Pathogenic Human Coronaviruses

Area of Science:

• Immunology
• Vaccinology
• Virology

Background:

• Vaccine-associated enhanced disease (VAED) presents diagnostic challenges, often confused with vaccine failure.
• Understanding VAED mechanisms like antibody-dependent enhancement (ADE) is crucial for vaccine safety.
• Pathogenic human coronaviruses (MERS-CoV, SARS-CoV-1, SARS-CoV-2) are key areas of investigation for VAED.

Purpose of the Study:

• To critically review the literature on VAED in pathogenic human coronaviruses.
• To highlight known and theoretical mechanisms of VAED, including ADE, antibody-enhanced disease (AED), and Th2-mediated pathology.
• To identify challenges in characterizing VAED in preclinical and clinical studies and propose future improvements.

Main Methods:

• Literature review of VAED in respiratory syncytial virus (RSV) and dengue virus vaccination.
• Critical analysis of studies on MERS-CoV, SARS-CoV-1, and SARS-CoV-2 vaccines concerning VAED.
• Examination of histopathological data and definitions of severe pathology in preclinical vaccine studies.

Main Results:

• Known VAED mechanisms include ADE, AED, and Th2-mediated pathology, exemplified by RSV and dengue studies.
• Preclinical studies on MERS-CoV and SARS-CoV-1 vaccines often suffer from poor data quality and inconsistent VAED definitions.
• Few mild VAED reports exist for SARS-CoV-2 preclinical models, with no clinical observations.

Conclusions:

• Inconsistent methodologies and data quality hinder the accurate assessment of VAED in coronavirus vaccine research.
• Improvements in histopathological analysis and standardized VAED definitions are necessary for future studies.
• Further research is needed to fully characterize and mitigate potential VAED risks associated with coronavirus vaccines.