The Viral and Vaccine Immunology Lab
All things COVID, Flu and HIV immunology
The ViralVaxLab is a clinical and pre-clinical immunology lab at the University of Melbourne, interested in understanding immunity to viral infections and translating that into novel and effective vaccine platforms. We study antibody, B and T cell responses to respiratory viruses (SARS-CoV-2, Influenza) and chronic infections (HIV, TB) in a variety of clinical cohorts and pre-clinical models.
Durable reprogramming of neutralizing antibody responses following Omicron breakthrough infection
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection of vaccinated individuals is increasingly common with the circulation of highly immune evasive and transmissible Omicron variants. Here, we report the dynamics and durability of recalled spike-specific humoral immunity following Omicron BA.1 or BA.2 breakthrough infection, with longitudinal sampling up to 8 months after infection. Both BA.1 and BA.2 infections robustly boosted neutralization activity against the infecting strain while expanding breadth against BA.4, although neutralization activity was substantially reduced for the more recent XBB and BQ.1.1 strains. Cross-reactive memory B cells against both ancestral and Omicron spike were predominantly expanded by infection, with limited recruitment of de novo Omicron-specific B cells or antibodies. Modeling of neutralization titers predicts that protection from symptomatic reinfection against antigenically similar strains will be durable but is undermined by new emerging strains with further neutralization escape.