Estimation of the contact rate in a seasonal SEIR model: application to chickenpox incidence in France

Deguen, Séverine; Thomas, Guy; Chau, Nguyen Phong

doi:10.1002/(sici)1097-0258(20000515)19:9<1207::aid-sim423>3.0.co;2-l

Cited by 28 publications

(26 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Transmission rates increased during school terms when children were aggregated, and declined during school holidays. Other studies of immunizing childhood infections, such as pertussis and chicken pox, have shown similar trends of increased transmission during school terms (London & Yorke 1973;Gomes et al 1999;Deguen et al 2000). Elsewhere, there is considerable debate as to the mechanistic basis of seasonality for directly transmitted pathogens (e.g.…”

Section: Introductionmentioning

confidence: 97%

Rural–urban gradient in seasonal forcing of measles transmission in Niger

Ferrari

Djibo²,

Grais³

et al. 2010

Proc. R. Soc. B.

View full text Add to dashboard Cite

Seasonally driven cycles of incidence have been consistently observed for a range of directly transmitted pathogens. Though frequently observed, the mechanism of seasonality for directly transmitted human pathogens is rarely well understood. Despite significant annual variation in magnitude, measles outbreaks in Niger consistently begin in the dry season and decline at the onset of the seasonal rains. We estimate the seasonal fluctuation in measles transmission rates for the 38 districts and urban centres of Niger, from 11 years of weekly incidence reports. We show that transmission rates are consistently in anti-phase to the rainfall patterns across the country. The strength of the seasonal forcing of transmission is not correlated with the latitudinal rainfall gradient, as would be expected if transmission rates were determined purely by environmental conditions. Rather, seasonal forcing is correlated with the population size, with larger seasonal fluctuation in more populous, urban areas. This pattern is consistent with seasonal variation in human density and contact rates due to agricultural cycles. The stronger seasonality in large cities drives deep inter-epidemic troughs and results in frequent local extinction of measles, which contrasts starkly to the conventional observation that large cities, by virtue of their size, act as reservoirs of measles.

show abstract

Section: Introductionmentioning

confidence: 97%

Rural–urban gradient in seasonal forcing of measles transmission in Niger

Ferrari

Djibo²,

Grais³

et al. 2010

Proc. R. Soc. B.

View full text Add to dashboard Cite

show abstract

“…In temperate regions, almost all individuals become infected with VZV during their lifetime, usually during childhood [1]. Several modelling studies have found that, similar to measles [2]–[6], VZV transmission is reduced during school holidays compared to termtime [5]–[7]. Two of these studies used historical data, from early 20 th Century Denmark [5] or from 1928–1973 in the USA [6].…”

Section: Introductionmentioning

confidence: 99%

The Effects of School Holidays on Transmission of Varicella Zoster Virus, England and Wales, 1967–2008

et al. 2014

View full text Add to dashboard Cite

BackgroundChanges in children’s contact patterns between termtime and school holidays affect the transmission of several respiratory-spread infections. Transmission of varicella zoster virus (VZV), the causative agent of chickenpox, has also been linked to the school calendar in several settings, but temporal changes in the proportion of young children attending childcare centres may have influenced this relationship.MethodsWe used two modelling methods (a simple difference equations model and a Time series Susceptible Infectious Recovered (TSIR) model) to estimate fortnightly values of a contact parameter (the per capita rate of effective contact between two specific individuals), using GP consultation data for chickenpox in England and Wales from 1967–2008.ResultsThe estimated contact parameters were 22–31% lower during the summer holiday than during termtime. The relationship between the contact parameter and the school calendar did not change markedly over the years analysed.ConclusionsIn England and Wales, reductions in contact between children during the school summer holiday lead to a reduction in the transmission of VZV. These estimates are relevant for predicting how closing schools and nurseries may affect an outbreak of an emerging respiratory-spread pathogen.

show abstract

“…For example, much work has been done on modeling the seasonal variation in transmission probabilities of measles from case reports data (Deguen, Thomas, and Chau, 2000;Wallinga, Teunis, and Kretzschmar, 2003). In particular, the time series susceptible infected recovered (TSIR) model (Finkenstadt and Grenfell, 2000) can be used to estimate reproduction numbers and other important quantities, and has provided new insights into the dynamics of measles transmission.…”

Section: Introductionmentioning

confidence: 99%

Infections with Varying Contact Rates: Application to Varicella

Whitaker

Farrington

2004

Biometrics

View full text Add to dashboard Cite

We develop methods for the analysis of infectious disease data when age-specific contact rates vary over time. Our methods are valid when contact rates vary slowly on the time scale of the infection process, and are applicable to a variety of data types including serial seroprevalence surveys and case reports. The methods exploit approximate endemic equilibria, and require numerical solution of an associated integral equation in age and time. We also estimate summary statistics such as time-dependent analogs of the basic reproduction number and critical immunization threshold. We illustrate the methods with data on varicella (chickenpox) in the United Kingdom.

show abstract

Estimation of the contact rate in a seasonal SEIR model: application to chickenpox incidence in France

Cited by 28 publications

References 14 publications

Rural–urban gradient in seasonal forcing of measles transmission in Niger

Rural–urban gradient in seasonal forcing of measles transmission in Niger

The Effects of School Holidays on Transmission of Varicella Zoster Virus, England and Wales, 1967–2008

Infections with Varying Contact Rates: Application to Varicella

Contact Info

Product

Resources

About