The Mucosal Immunity in Human Coronavirus Challenge (MusiCC) project is conducting a CHIM study to expose vaccinated volunteers to the Omicron BA.5 subvariant of SARS-CoV-2. The goal is to elucidate the immune responses required to protect against breakthrough infection.
- Jackson 2024 found that:
- Only a low percentage (14%) of seropositive subjects exhibited transient infection with detectable viral kinetics when infected with pre-alpha SARS-CoV-2, but exhibited no persistent replication.
- 39% of subjects developed breakthrough community acquired infections with omicron after the study.
- The findings suggest a need for CHIMs using newer SARS-CoV-2 variants to reflect real-world infection dynamics, necessitating the above mentioned study.