1. Inducing Herd Immunity against Seasonal Influenza in Long-Term Care Facilities through Employee Vaccination Coverage: A Transmission Dynamics Model.
- Author
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Wendelboe AM, Grafe C, McCumber M, and Anderson MP
- Subjects
- Computational Biology, Disease Outbreaks prevention & control, Disease Outbreaks statistics & numerical data, Epidemiological Monitoring, Health Personnel, Humans, Infectious Disease Transmission, Professional-to-Patient prevention & control, Influenza, Human epidemiology, Influenza, Human transmission, Linear Models, Long-Term Care, Models, Immunological, Models, Statistical, New Mexico epidemiology, Residential Facilities, Seasons, Stochastic Processes, Vaccination, Immunity, Herd, Influenza, Human immunology
- Abstract
Introduction: Vaccinating healthcare workers (HCWs) in long-term care facilities (LTCFs) may effectively induce herd immunity and protect residents against influenza-related morbidity and mortality. We used influenza surveillance data from all LTCFs in New Mexico to validate a transmission dynamics model developed to investigate herd immunity induction., Material and Methods: We adjusted a previously published transmission dynamics model and used surveillance data from an active system among 76 LTCFs in New Mexico during 2006-2007 for model validation. We used a deterministic compartmental model with a stochastic component for transmission between residents and HCWs in each facility in order to simulate the random variation expected in such populations., Results: When outbreaks were defined as a dichotomous variable, our model predicted that herd immunity could be induced. When defined as an attack rate, the model demonstrated a curvilinear trend, but insufficiently strong to induce herd immunity. The model was sensitive to changes in the contact parameter β but was robust to changes in the visitor contact probability., Conclusions: These results further elucidate previous studies' findings that herd immunity may not be induced by vaccinating HCWs in LTCFs; however, increased influenza vaccination coverage among HCWs reduces the probability of influenza infection among residents.
- Published
- 2015
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