Modeling the waning and boosting of immunity from infection or vaccination. (21st July 2020)

• Record Type: Journal Article
• Authors: Carlsson, Rose-Marie; Childs, Lauren M; Feng, Zhilan; Glasser, John W; Heffernan, Jane M; Li, Jing; Röst, Gergely
• Is Part Of: Journal of theoretical biology. Volume 497(2020)
• Publication Date: 2020-07-21
• Subjects: Mathematical epidemiology -- Waning and boosting of immunity -- Vaccination -- Age- and immunity-structured population -- Immuno-epidemiology; 92D25 -- 92D30; Biology -- Periodicals; Biological Science Disciplines -- Periodicals; Biology -- Periodicals; Biologie -- Périodiques; Theoretische biologie; Biology; Periodicals; 571.05
• DOI: 10.1016/j.jtbi.2020.110265
• Languages: English
• ISSNs: 0022-5193

Abstract

Highlights: We have developed a mathematical model to quantify the effects of the waning and boosting of immunity in a population. The model delineates the population by immune system status (due to vaccination and natural infection), and also includes the effects of the age of individuals (as age affects individual characteristics that affect disease transmission such as contact rates). We have derived the basic and control reproduction numbers given age and immunity population structure. The model is parameterized to study the waning and boosting of pertussis immunity in Sweden, under the Sweden vaccination schedule. Our numerical simulations show the implementation of vaccination and booster vaccines decreases the total incidence of pertussis in the population. Our results also confirm the age groups chosen by Swedish public health decision makers for the introduction of vaccination booster doses, in school-age children and adolescents. We conclude that our model can be employed to determine pertussis vaccination booster dose age groups in other populations, an area for future study. Abstract: Immunity following natural infection or immunization may wane, increasing susceptibility to infection with time since infection or vaccination. Symptoms, and concomitantly infectiousness, depend on residual immunity. We quantify these phenomena in a model population composed of individuals whose susceptibility, infectiousness, and symptoms all vary with immune status. We also model age, which affects contact, vaccination and possibly waning rates. The resurgences of pertussis that have been observed wherever effective vaccination programs have reduced typical disease among young children follow from these processes. As one example, we compare simulations with the experience of Sweden following resumption of pertussis vaccination after the hiatus from 1979 to 1996, reproducing the observations leading health authorities to introduce booster doses among school-aged children and adolescents in 2007 and 2014, respectively. Because pertussis comprises a spectrum of symptoms, only the most severe of which are medically attended, accurate models are needed to design optimal vaccination programs where surveillance is less effective.