T Cell Responses Correlate with Self-Reported Disease Severity and Neutralizing Antibody Responses Predict Protection...

Area of Science:

• Immunology
• Vaccinology
• Infectious Diseases

Background:

• Adaptive immunity plays a crucial role in vaccine-mediated protection against SARS-CoV-2.
• Understanding the distinct roles of neutralizing antibodies and T cell responses is vital for assessing vaccine efficacy.

Purpose of the Study:

• To investigate the relationship between adaptive immune responses and protection following SARS-CoV-2 vaccination.
• To evaluate the impact of different vaccine types on neutralizing antibody and T cell responses.
• To determine predictors of breakthrough SARS-CoV-2 infections and disease severity.

Main Methods:

• Prospective study of 677 vaccinated individuals.
• Assessment of neutralizing antibody (NAb) and T cell responses via blood donation.
• Follow-up surveys to track breakthrough infections and disease severity.

Main Results:

• Moderna vaccines elicited higher NAb levels than Pfizer or Johnson & Johnson.
• NAb levels declined over time for Pfizer and Johnson & Johnson vaccines.
• NAb responses were predictive of protection against breakthrough infection.
• T cell responses did not differ significantly between vaccine types and remained stable.
• T cell responses were associated with reduced COVID-19 disease severity, not infection prevention.

Conclusions:

• Neutralizing antibody responses are key correlates of protection against SARS-CoV-2 infection post-vaccination.
• T cell-mediated immunity may contribute to mitigating disease severity but not preventing infection.
• Findings inform vaccine effectiveness evaluations and strategies.