scholarly journals Scheduling of users with markovian time-varying transmission rates

2013 ◽  
Vol 41 (1) ◽  
pp. 129-140 ◽  
Author(s):  
Fabio Cecchi ◽  
Peter Jacko
2021 ◽  
Author(s):  
Alexander Chudik ◽  
M. Hashem Pesaran ◽  
Alessandro Rebucci

AbstractThis paper estimates time-varying COVID-19 reproduction numbers worldwide solely based on the number of reported infected cases, allowing for under-reporting. Estimation is based on a moment condition that can be derived from an agent-based stochastic network model of COVID-19 transmission. The outcomes in terms of the reproduction number and the trajectory of per-capita cases through the end of 2020 are very diverse. The reproduction number depends on the transmission rate and the proportion of susceptible population, or the herd immunity effect. Changes in the transmission rate depend on changes in the behavior of the virus, re-flecting mutations and vaccinations, and changes in people’s behavior, reflecting voluntary or government mandated isolation. Over our sample period, neither mutation nor vaccination are major factors, so one can attribute variation in the transmission rate to variations in behavior. Evidence based on panel data models explaining transmission rates for nine European countries indicates that the diversity of outcomes resulted from the non-linear interaction of mandatory containment measures, voluntary precautionary isolation, and the economic incentives that gov-ernments provided to support isolation. These effects are precisely estimated and robust to various assumptions. As a result, countries with seemingly different social distancing policies achieved quite similar outcomes in terms of the reproduction number. These results imply that ignoring the voluntary component of social distancing could introduce an upward bias in the estimates of the effects of lock-downs and support policies on the transmission rates.JEL ClassificationD0, F6, C4, I120, E7


2020 ◽  
Author(s):  
Lee Worden ◽  
Rae Wannier ◽  
Micaela Neus ◽  
Jennifer C. Kwan ◽  
Alex Y. Ge ◽  
...  

We estimated time-varying reproduction numbers of COVID-19 transmission in counties and regions of California and in states of the United States, using the Wallinga-Teunis method of estimations applied to publicly available data. The serial interval distribution assumed incorporates wide uncertainty in delays from symptom onset to case reporting. This assumption contributes smoothing and a small but meaningful increase in numerical estimates of reproduction numbers due to the likely existence of secondary cases not yet reported. Transmission in many areas of the U.S. may not yet be controlled, including areas in which case counts appear to be stable or slowly declining.


2020 ◽  
Vol 16 (9) ◽  
pp. e1008124
Author(s):  
Mikael Jagan ◽  
Michelle S. deJonge ◽  
Olga Krylova ◽  
David J. D. Earn

Author(s):  
Xingjie Hao ◽  
Shanshan Cheng ◽  
Degang Wu ◽  
Tangchun Wu ◽  
Xihong Lin ◽  
...  

ABSTRACTVigorous non-pharmaceutical interventions have largely suppressed the COVID-19 outbreak in Wuhan, China. We developed a susceptible-exposed-infectious-recovered model to study the transmission dynamics and evaluate the impact of interventions using 32,583 laboratory-confirmed cases from December 8, 2019 till March 8, 2020, accounting for time-varying ascertainment rates, transmission rates, and population movements. The effective reproductive number R0 dropped from 3.89 (95% credible interval: 3.79-4.00) before intervention to 0.14 (0.11-0.28) after full-scale multi-8 pronged interventions. By projection, the interventions reduced the total infections in Wuhan by 96.5% till March 8. Furthermore, we estimated that 79% (lower bound: 60%) of the total infections were unascertained, potentially including asymptomatic and mild-symptomatic cases. The probability of resurgence was 0.22 and 0.10 based on models with 79% and 60% infections unascertained, respectively, assuming interventions were lifted after a 14-day period of no new ascertained infections. These results provide important implications for continuing surveillance and interventions to eventually contain the outbreak.


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