CASCADIA: A prospective community-based study protocol for assessing SARS-CoV-2 vaccine effectiveness in children and adults utilizing a remote nasal swab collection and web-based survey design

Introduction Although SARS-CoV-2 vaccines were first approved under Emergency Use Authorization by the FDA in late 2020 for adults, approval for young children 6 months to < 5 years of age did not occur until 2022. Understanding real world vaccine effectiveness in the setting of emerging variants is critical. The primary goal of this study is to evaluate SARS-CoV-2 vaccine effectiveness (VE) against infection among children aged >6 months and adults aged <50 years. Methods CASCADIA is a four-year community-based prospective study of SARS-CoV-2 VE among adult and pediatric populations aged 6 months to 49 years in Oregon and Washington. At enrollment and regular intervals, participants complete a sociodemographic questionnaire. Individuals provide a blood sample at enrollment and annually thereafter, with additional, optional blood draws after infection and vaccination. Participants complete weekly self-collection of anterior nasal swabs and symptom questionnaires. Swabs are tested for SARS-CoV-2 and other respiratory pathogens by RT-PCR, with results of selected pathogens returned to participants; nasal swabs with SARS-CoV-2 detected will undergo whole genome sequencing. Participants who report symptoms outside of their weekly swab collection and symptom survey are asked to collect an additional swab. Participants who test positive for SARS-CoV-2 undergo serial swab collection every three days for three weeks. Serum samples are tested for SARS-CoV-2 antibody by binding and neutralization assays. Analysis Cox regression models will be used to estimate the hazard ratio associated with SARS-CoV-2 vaccination among the pediatric and adult population, controlling for demographic factors and potential confounders, including clustering within households. Ethics and dissemination All study materials including the protocol, consent forms, participant communication and recruitment materials, and data collection instruments were approved by the Kaiser Permanente Northwest (KPNW) Institutional Review Board, the IRB of record for the study. Strengths/Limitations ### Competing Interest Statement HYC reports consulting with Ellume, Pfizer, The Bill and Melinda Gates Foundation, Glaxo Smith Kline, and Merck. HYC received research funding from Gates Ventures, Sanofi Pasteur, and support and reagents from Ellume and Cepheid outside of the submitted work. JAE reports research support from Gates Ventures, AstraZeneca, GlaxoSmithKline, Merck, and Pfizer, and consulting with Sanofi Pasteur, AstraZeneca, Teva Pharmaceuticals, and Meissa Vaccines, outside of the submitted work. ALN reports research funding from Pfizer and Vir Biotechnology, outside of the submitted work. JLK reports research funding from Vir Biotechnology, outside of the submitted work. ### Funding Statement This study was supported by the Centers for Disease Control and Prevention contract 75D30121C12297 to Kaiser Foundation Hospitals. ### 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: All study materials including the protocol, consent forms, participant communication and recruitment materials, and data collection instruments were approved by the Kaiser Permanente Northwest (KPNW) Institutional Review Board, the IRB of record for the study. 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 All data produced in the present study are available upon reasonable request to the authors