Seeking the optimal schedule for chickenpox vaccination in Canada: Using an agent-based model to explore the impact of dose timing, coverage and waning of immunity on disease outcomes

What We Know Now: An Economic Evaluation of Chickenpox Vaccination and Dose Timing Using an Agent-Based Model

“…Recent studies have shown that primary vaccine failure has more of an impact on chickenpox breakthrough illness than secondary vaccine failure. 15,31 However, schedule SDI also led to a higher age of chickenpox infection and a slightly higher rate of shingles, and therefore higher overall costs. Although, the fact that the second dose for schedule SDI was provided earlier then the second dose with LDI also resulted in schedule SDI having higher associated healthcare costs, which may have reduced its overall costeffectiveness.…”

“…We constructed an ABM that simulates VZV transmission, chickenpox, and shingles disease and health outcomes, as described in Rafferty et al, 14,15 with the full model code available at McDonald et al (2018). 18 The ABM was previously fit to Alberta data before the implementation of chickenpox vaccination and checked for consistency with data postvaccination.…”

“…18 The ABM was previously fit to Alberta data before the implementation of chickenpox vaccination and checked for consistency with data postvaccination. 14,15 We simulated a population of 500 000 agents (persons) within a distancebased contact network. Following initial chickenpox infection, the time until an agent becomes susceptible to shingles is based on their individual waning immunity timer (ie, time protected from shingles) with the possibility for boosting of immunity.…”

“…We aimed to test the cost-effectiveness of chickenpox vaccination in Alberta, Canada, using a previously published ABM of chickenpox and shingles, 14,15 with updated data on the health utilization, costs, and utilities associated with chickenpox disease and vaccination. Furthermore, using our ABM we aimed to compare the cost-effectiveness of chickenpox vaccination under the 2 most commonly used schedules in Canada: (1) schedule LDI and (2) schedule SDI.…”

A Dynamic Compartmental Model to Explore the Optimal Strategy of Varicella Vaccination: An Epidemiological Study in Jiangsu Province, China

“…For the two-dose vaccination schedule there is continuous debate about whether a short-term (months) or longer term (years) interval should be kept. Some hold that a short interval between two doses would lead to a lower risk of varicella breakthrough infections, but with less durable protection over time, and a long interval would produce durable immunity, but children might face a higher risk of breakthrough infections in their early life [ 25 ]. A recent study [ 25 ] used an agent-based-model to compare the effectives of the two vaccination schedules: (1) first dose at 12 months, second dose at 18 months, and (2) first dose at 12 months, second dose at 4–6 years.…”