Evidence of Leaky Protection Following COVID-19 Vaccination and SARS-CoV-2 Infection in a US Correctional Facility Population

Whether SARS-CoV-2 infection and COVID-19 vaccines confer exposure-dependent (“leaky”) protection remains unknown. We examined the effect of prior infection and vaccination on infection risk among residents of Connecticut correctional facilities during periods of predominant Omicron and Delta transmission. Residents with cell, unit, and no documented exposures to SARS-CoV-2 infected residents were matched by facility and date. During the Omicron period, prior infection and vaccination reduced the infection risk of residents without a documented exposure (Hazards ratio: infection, 0.36 [0.25-0.54]; vaccination, 0.57 [0.42-0.78]) and with cellblock exposures (infection, 0.61 [0.49-0.75]; vaccination, 0.69 [0.58-0.83]) but not with cell exposures (infection, 0.89 [0.58-1.35]; vaccination, 0.96 [0.64-1.46]). Associations were similar during the Delta period and when analyses were restricted to residents who underwent testing. These findings suggest that SARS-CoV-2 infection and COVID-19 vaccination may be leaky, highlighting the potential benefits of pairing vaccination with non-pharmaceutical interventions in densely crowded settings. ### Competing Interest Statement A.I.K is as an expert panel member for Reckitt Global Hygiene Institute, and a consultant for Tata Medical and Diagnostics and Regeneron Pharmaceuticals and has received grants related to COVID-19 research outside the scope of the proposed work from Regeneron Pharmaceuticals and Tata Medical and Diagnostics. W.L.S. was an investigator for a research agreement, through Yale University, from the Shenzhen Center for Health Information for work to advance intelligent disease prevention and health promotion; collaborates with the National Center for Cardiovascular Diseases in Beijing; is a technical consultant to Hugo Health, a personal health information platform, and co-founder of Refactor Health, an AI-augmented data management platform for healthcare; and has received grants related to COVID-19 research outside the scope of the proposed work from Regeneron Pharmaceutical. Other authors declare no conflict of interest. ### Funding Statement This work was supported by a contract from the Connecticut Department of Public Health (Emerging Infections Program 2021-0071 to A.I.K.), the Raj and Indra Nooyi Professorship (to A.I.K), and the Merck Investigator Studies Program (to W.L.S. and A.I.K.). The funders did not have a role in the design or implementation of the study nor the decision to publish the study. The study and its findings are the responsibility of the authors and do not reflect the views of the Connecticut Department of Correction. ### 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: The Yale University Institutional Review Board waived ethical approval for this work as it was determined to be a public health surveillance activity. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. 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 used in this study belongs to the Connecticut Department of Correction. Qualified researchers may submit a data share request for de-identified patient level data by contacting the corresponding author with a detailed description of the research question and setting up a data use agreement with the Department of Corrections. Code used to perform power calculations and conduct statistical analyses is available in the following repository: https://github.com/lindm89/CT\_DOC\_Dose\_Effect\_Vax.git.