Estimating seroprevalence of SARS-CoV-2 infection after a highly contagious Omicron outbreak: A cross sectional study in a university setting

Abstract

AbstractObjectiveThis study aimed to investigate the seroprevalence of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) antibodies among individuals aged 18 years and olderDesignProspective cohort study.SettingsPopulation-based study was conducted within the Arizona State University (ASU) community.ParticipantsThe study recruited 1,397 adult participants that volunteered over a period of three days (March 1-March 3 of 2022).Primary outcome measuresSeroprevalence was conducted in the community to assess the presence of SARS-CoV-2-specific antibodies resulting from previous exposure to SARS-CoV-2 and/or vaccination.ResultsThe seroprevalence of anti-receptor binding domain (RBD) antibodies was found to be 96.3% using a semi-quantitative chemiluminescent immunoassay and 98% using an electrochemiluminescent immunoassay. For anti-nucleocapsid (NC) antibodies, the seroprevalence was 39.1% by an ELISA assay and 41.4% by an electrochemiluminescent immunoassay. Individuals that experienced breakthrough infections exhibited the highest levels of anti-RBD antibodies. Additionally, saliva samples showed promise as a potential diagnostic biofluid for measuring antibody levels, as they exhibited a strong correlation with the data obtained from serum samples.ConclusionAccurate estimation of population-based serosurveillance for SARS-CoV- 2 will monitor the trend of infection in the community and delineate the geographical spread of the infection. Cumulative incidence of SARS-CoV-2 infection during and after outbreaks is crucial for informing the development of effective risk mitigation protocols within the community. Protocols may include measures such as encouraging booster shots, extending mask mandates, or transitioning to online classes. Serosurveys repeated at regular intervals can also guide containment measures in communities and prompt response to future outbreaks.Strengths and limitations of this studyWe simultaneously investigated active infection and seroprevalence for the university population.Our study was strengthened by having the participants’ self-report data independently validated with diagnostic tests.Saliva samples could be a potential diagnostic biofluid for measuring antibody levels.Our study was performed within the university setting therefore it only reflects the COVID-19 situation within that community.The number of breakthrough infections and the longitudinal samples were small, thus requiring confirmation.