My PhD work mainly focused on understanding the virus evolution in the presence of immune responses and how immune response evolves over time after antigen exposure. Currently, I am developing a method that can detect the underreported infections in healthcare workers and immunocompromised individuals. Our analysis shows the ineffectiveness of the ChAdOx1-nCoV19 vaccine to protect from COVID-19 infection during the Omicron wave in both cohorts. The infection rate during the Omicron wave was similar in both cohorts, irrespective of their antibody titers.