The effect of local extended families in epidemics: the case of COVID-19 deaths in the US

Abstract Do extended family members that live near each other significantly affect the dynamics of large respiratory infectious disease outbreaks? While current epidemiological consensus recognizes household family as relevant, extended family (kin) groups are not viewed as playing an especial role, disregarding evidence of the frequent and unique support they provide each other. Indeed, if extended family was relevant, this disregard would likely lead to deficiencies in advice, modeling, and preparedness during an epidemic as neither the interaction patterns with extended family nor the effectiveness of non-pharmaceutical interventions (NPIs) on them are known. Here, through the creation of the first large-scale data set of obituaries in the US for research purposes (~ 1.4 million deaths), we show for the first time evidence that between the beginning of 2020 and end of 2022 (the height of the COVID-19 pandemic) there were surges of deaths among kin members living in the same cities, consistently spanning summer periods. The kin surges we observe started simultaneously with overall COVID-19 population surges but continued even as the overall surges subsided. These surge patterns are consistent with extended families maintaining contact even through strict periods of NPIs implementation, potentially making them an unrecognized reservoir of disease spread helping outbreaks persist. Further, we find indications that kin-related deaths are more prevalent among genetic kin and display gender heterogeneity. Our results call for a renewal on research on infection-relevant contact patterns among extended US families and on the effects that NPIs may have towards these contacts. Competing Interest Statement The authors have declared no competing interest. Funding Statement This study did not receive any funding. 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: IRB of George Mason University waived ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the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, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability Data is available at the link below, with the limitation that names have been obfuscated for privacy protection, certain data has been aggregated, and original data is unavailable due to data use agreements.