Estimation of Total Immunity to SARS-CoV-2 in Texas

Given the underestimate of seroprevalence in the US due to insufficient testing, accurate estimates of population immunity to SARS-CoV-2 or vaccinations do not exist. Although model-based estimates have been proposed, they require inputting unknown parameters such as viral reproduction number, longevity of immune response, and other dynamic factors. In contrast to a model-based approach for estimating population immunity, or simplistic summing of natural- and vaccine-induced immunity, the current study presents a data-driven statistical procedure for estimating the total immunity rate in a region using prospectively collected serological data along with state-level vaccination data. We present a detailed procedure so that efforts can be replicated regionally to inform policy-making decisions relevant to SARS-CoV-2. Specifically, we conducted a prospective longitudinal statewide cohort serological survey with 10,482 participants and more than 14,000 blood samples beginning on September 30, 2020. Along with Department of State Health Services vaccination data, as of July 4, 2021, the estimated percentage of those with naturally occurring antibodies to SARS-CoV-2 in Texas is 35.3% (95% CI = (33.7%, 36.9%) and total estimated immunity is 69.1%. We conclude the seroprevalence of SARS-CoV-2 is 4 times higher than the state-confirmed COVID-19 cases (8.8%). This methodology is integral to pandemic preparedness. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Protocols ### Funding Statement Texas DSHS # ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This research was approved by the UTHealth Institutional Review Board and Texas Department of State and Health Services (DSHS). All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The data are in process of being collected over a period of 2 years. However summaries of the data are publicly available within the referenced URLs in the paper (the Texas CARES public dashboard: https://sph.uth.edu/projects/texascares/dashboard )