Corrigendum to“Silent circulation of poliovirus in small populations”[Infectious Disease Modeling 2(2017)431e440]

An error in a previous publication in the calculation of the average age at first infection for the model is corrected here.The average age at first infection for the effective contact rates used to generate the data ranges from 1.2 to 3.3 years of age instead of 3e5 years of age as advertised in the previous version of the paper.This change has an effect on the force of infection generated by this model.In this corrigendum,we demonstrate the correct method to calculate the average age at first infection for the model.We compare the forces of infection that correspond to these ages in our model with the forces of infection in other endemic populations.We show that the modified age range corresponds to forces of infection which are higher than those that are known to exist in historical studies of polioendemic regions.Thus,the results in the paper have limited applicability to real-world endemic situations.

Silent circulation of poliovirus in small populations

Background:Small populations that have been isolated by conflict make vaccination and surveillance difficult,threatening polio eradication.Silent circulation is caused by asymptomatic infections.It is currently not clear whether the dynamics of waning immunity also influence the risk of silent circulation in the absence of vaccination.Such circulation can,nevertheless,be present following a declaration of elimination as a result of inadequate acute flaccid paralysis surveillance(AFPS)or environmental surveillance(ES).Methods:We have constructed a stochastic model to understand how stochastic effects alter the ability of small populations to sustain virus circulation in the absence of vaccination.We analyzed how the stochastic process determinants of the duration of silent circulation that could have been detected by ES were affected by R0,waning dynamics,population size,and AFPS sensitivity in a discrete individual stochastic model with homogeneous contagiousness and random mixing.We measured the duration of silent circulation both by the interval between detected acute flaccid paralysis(AFP)cases and the duration of circulation until elimination.Results:As R0 increased and population size increased,the interval between detected AFP cases and the duration of circulation until elimination increased.As AFPS detection rates decreased,the interval between detected AFP cases increased.There was up to a 22%chance of silent circulation lasting for more than 3 years with 100%AFP detection.The duration of silent circulation was not affected by the waning immunity dynamics.Conclusion:We demonstrated that small populations have the potential to sustain prolonged silent circulation.Surveillance in these areas should be intensified before declaring elimination.To further validate these conclusions,it is necessary to realistically relax the simplifying assumptions about mixing and waning.

Performance evaluation framework of Wyoming connected vehicle pilot deployment program: summary of Phase 2 pre-deployment efforts and lessons learned

Purpose–This paper aims to present a summary of the performance measurement and evaluation plan of the Wyoming connected vehicle(CV)Pilot Deployment Program(WYDOT Pilot).Design/methodology/approach–This paper identified 21 specific performance measures as well as approaches to measure the benefits of the WYDOT Pilot.An overview of the expected challenges that might introduce confounding factors to the evaluation effort was outlined in the performance management plan to guide the collection of system performance data.Findings–This paper presented the data collection approaches and analytical methods that have been established for the real-life deployment of the WYDOT CV applications.Five methodologies for assessing 21 specific performance measures contained within eight performance categories for the operational and safety-related aspects.Analyses were conducted on data collected during the baseline period,and pre-deployment conditions were established for 1 performance measures.Additionally,microsimulation modeling was recommended to aid in evaluating the mobility and safety benefits of the WYDOT CV system,particularly when evaluating system performance under various CV penetration rates and/or CV strategies.Practical implications–The proposed performance evaluation framework can guide other researchers and practitioners identifying the best performance measures and evaluation methodologies when conducting similar research activities.Originality/value–To the best of the authors’knowledge,this is thefirst research that develops performance measures and evaluation plan for low-volume rural freeway CV system under adverse weather conditions.This paper raised some early insights into how CV technology might achieve the goal of improving safety and mobility and has the potential to guide similar research activities conducted by other agencies.