Epidemiological game-theory dynamics of chickenpox vaccination in the USA and Israel

Abstract

The general consensus from epidemiological game-theory studies is that vaccination coverage driven by self-interest (Nash vaccination) is generally lower than group-optimal coverage (utilitarian vaccination). However, diseases that become more severe with age, such as chickenpox, pose an exception to this general consensus. An individual choice to be vaccinated against chickenpox has the potential to harm those not vaccinated by increasing the average age at infection and thus the severity of infection as well as those already vaccinated by increasing the probability of breakthrough infection. To investigate the effects of these externalities on the relationship between Nash and utilitarian vaccination coverages for chickenpox, we developed a game-theory epidemic model that we apply to the USA and Israel, which has different vaccination programmes, vaccination and treatment costs, as well as vaccination coverage levels. We find that the increase in chickenpox severity with age can reverse the typical relationship between utilitarian and Nash vaccination coverages in both the USA and Israel. Our model suggests that to obtain herd immunity of chickenpox vaccination, subsidies or external regulation should be used if vaccination costs are high. By contrast, for low vaccination costs, improving awareness of the vaccine and the potential cost of chickenpox infection is crucial.

The influence of altruism on influenza vaccination decisions

“…Assigning the personal disutility to mortality is nearly impossible, because individuals would give infinitely low values, when asked to assign the disutility to their mortality. As a result, in economic analyses of vaccination, including health decision modelling, it is standard to assign monetary values to all outcomes, including health or metaphysical outcomes [6][7][8]34].…”

Outbreaks of Varicella Zoster in a Military Nursing Institute: Infection Control in Hospital and Institutional Environments

“…VZ vaccination is included in recommended vaccination schedules of many affluent countries worldwide as per the world health organization (WHO) recommendations of 80% vaccination coverage under herd immunization strategy. Epidemiological game-theory revealed that Nashvaccination coverage by self-interest was lower compared with group-optimal utilitarian vaccination coverage, with the exception of VZ (15,16). The availability of MMRV with measles, mumps, and rubella suits incorporation in universal immunization program, albeit even single-dose VZ vaccination remains prohibitively expensive on a large scale and only few countries fund the vaccine through national health systems (1,15,16).…”

“…Epidemiological game-theory revealed that Nashvaccination coverage by self-interest was lower compared with group-optimal utilitarian vaccination coverage, with the exception of VZ (15,16). The availability of MMRV with measles, mumps, and rubella suits incorporation in universal immunization program, albeit even single-dose VZ vaccination remains prohibitively expensive on a large scale and only few countries fund the vaccine through national health systems (1,15,16). However, targeted vaccinations of HCP, transplant recipients and susceptible adolescents are proven cost-effective in high-income countries and likewise recommended by Indian Academy of Pediatrics (1,5).…”

Mathematical models of the interplay between individual vaccinating decisions and disease dynamics: a need for closer integration of models and data

“…This can occur in game theoretical models of chickenpox vaccination, where the Nash equilibrium vaccine coverage can actually exceed the socially optimal vaccine coverage. 13 Among other predictions, these models have suggested that a universal influenza vaccine conferring long-lasting immunity could actually increase the frequency of occasional but severe epidemics, 24 that free-riding behavior could emerge surprisingly quickly in a new pediatric vaccine program, even in the first few years, 25 that long cycles in disease prevalence could emerge when self-interested vaccination decisions are based on delayed information, 18 and how imperfect vaccines can aggravate the social dilemma of voluntary vaccination. 26 The models have also suggested solutions to the social dilemma, such as taxes and subsidies, 9 or offering several years of free vaccines to individuals who pay for one year of vaccination, 27 though it has also been shown that some incentive programs could be detrimental.…”

“…8,[10][11][12] However, others have explored exceptions to the rule, which may occur when taxes or subsidies are applied 9 or for specific disease features such as when infection severity increases with age. 13 Even when these models are not strictly game theoretical (i.e., seeking to prove that a vaccine coverage level is a Nash equilibrium), they are motivated by the problem of feedback between disease dynamics and vaccinating behavior.…”