In recent months, studies have raised the possibility that certain emerging SARS-CoV-2 variants evolved to escape antibody immune surveillance, elicited by previous infection, immunization, or by monoclonal antibody treatments.
COVID-19 immune signatures reveal stable antiviral T cell function despite declining humoral responses
Immune mechanisms following SARS-CoV-2 infection remain largely unknown. For instance, while it is evident that COVID-19 manifests itself in a wide range of outcomes, it is unclear if differences in disease severity are associated with specific immunological determinants.
Viruses mutate naturally as they replicate. Generally, most mutations are not a serious concern for human health or public health strategies.
When our immune system recovers from any given infection, it often remembers the aggressor long after it is gone. This process is referred to as immunological memory.
This study reported that individuals with pre-existing immunity have 10-20 times higher SARS-CoV-2 antibody titers than naïve individuals after the first dose.