TY - JOUR
T1 - Heterogeneity in susceptibility to infection can explain high reinfection rates
AU - Rodrigues, Paula Cristiana Costa Garcia da Silva Patricio
AU - Margheri, Alessandro
AU - Rebelo, Carlota
AU - Gomes, M. Gabriela M.
N1 - Funding Information:
Research supported by Fundação Calouste Gulbenkian (FCG), Fundação para a Ciência e a Tecnologia (Basal Fund 2008 - ISFL/1/209 and Fellowship SFRH/BD/30168/2006) and European Commission (Grant MEXT-CT-2004-14338).
PY - 2009/7/21
Y1 - 2009/7/21
N2 - Heterogeneity in susceptibility and infectivity is inherent to infectious disease transmission in nature. Here we are concerned with the formulation of mathematical models that capture the essence of heterogeneity while keeping a simple structure suitable of analytical treatment. We explore the consequences of host heterogeneity in the susceptibility to infection for epidemiological models for which immunity conferred by infection is partially protective, known as susceptible-infected-recovered-infected (SIRI) models. We analyze the impact of heterogeneity on disease prevalence and contrast the susceptibility profiles of the subpopulations at risk for primary infection and reinfection. We present a systematic study in the case of two frailty groups. We predict that the average rate of reinfection may be higher than the average rate of primary infection, which may seem paradoxical given that primary infection induces life-long partial protection. Infection generates a selection mechanism whereby fit individuals remain in S and frail individuals are transferred to R. If this effect is strong enough we have a scenario where, on average, the rate of reinfection is higher than the rate of primary infection even though each individual has a risk reduction following primary infection. This mechanism may explain high rates of tuberculosis reinfection recently reported. Finally, the enhanced benefits of vaccination strategies that target the high-risk groups are quantified.
AB - Heterogeneity in susceptibility and infectivity is inherent to infectious disease transmission in nature. Here we are concerned with the formulation of mathematical models that capture the essence of heterogeneity while keeping a simple structure suitable of analytical treatment. We explore the consequences of host heterogeneity in the susceptibility to infection for epidemiological models for which immunity conferred by infection is partially protective, known as susceptible-infected-recovered-infected (SIRI) models. We analyze the impact of heterogeneity on disease prevalence and contrast the susceptibility profiles of the subpopulations at risk for primary infection and reinfection. We present a systematic study in the case of two frailty groups. We predict that the average rate of reinfection may be higher than the average rate of primary infection, which may seem paradoxical given that primary infection induces life-long partial protection. Infection generates a selection mechanism whereby fit individuals remain in S and frail individuals are transferred to R. If this effect is strong enough we have a scenario where, on average, the rate of reinfection is higher than the rate of primary infection even though each individual has a risk reduction following primary infection. This mechanism may explain high rates of tuberculosis reinfection recently reported. Finally, the enhanced benefits of vaccination strategies that target the high-risk groups are quantified.
KW - Interventions
KW - Partial immunity
KW - Tuberculosis
UR - http://www.scopus.com/inward/record.url?scp=67349185841&partnerID=8YFLogxK
U2 - 10.1016/j.jtbi.2009.03.013
DO - 10.1016/j.jtbi.2009.03.013
M3 - Article
C2 - 19306886
SN - 0022-5193
VL - 259
SP - 280
EP - 290
JO - Journal Of Theoretical Biology
JF - Journal Of Theoretical Biology
IS - 2
ER -