Mathematical modeling and analysis of chickenpox transmission with vaccination strategies

Chickenpox, caused by the Varicella-Zoster Virus (VZV), remains one of the most common vaccine-preventable infectious diseases worldwide. This paper develops and analyzes an SVEIR (Susceptible-Vaccinated-Exposed-Infectious-Recovered) compartmental model that incorporates newborn vaccination, first-dose and second-dose vaccination, and waning vaccine-induced immunity. The basic reproduction number is derived via the next-generation matrix method, and the local stability of the disease-free and endemic equilibrium is established using the Routh-Hurwitz criterion. Numerical simulation over a 26-week horizon compare four vaccination scenarios: no vaccination, only newborn vaccination, only first-dose vaccination, and a combined strategy. Results show that single-strategy vaccination reduces but does not eliminate transmission, whereas the combined strategy produces the largest and fastest reduction in the infectious population, supporting the adoption of multi-mechanism vaccination policies.