Periodicity of varicella-zoster virus in the presence of immune boosting and clinical reinfection with varicella

Table 1 Model parameters

Parameter	Notation	Base value, refs.	Range
Varicella transmission coefficient	β	325 [27]	120–500
Rate of becoming infectious with varicella	ω	26 [21]	20–32
the base value corresponds to the average latent period of ≈ 14 days
Varicella recovery rate	γ	50 [21]	40–60
the base value corresponds to the average infectious period of ≈ 7.3 days
Loss of full immunity rate	σ	0.10 [4,9,17]	0.0125–4.0
the base value corresponds to the average duration of “full” immunity of 10 years
Varicella force of infection reduction coefficient for those	ζ	0.10 [assumed]	0.0–1.0
who become reinfected following clearance of varicella
Varicella force of infection reduction coefficient for those	α	0.90 [assumed]	0.0–1.0
who become reinfected following HZ attack
Boosting coefficient	κ	3.0 [assumed]	0.0–20.0
Birth/death rate	μ	0.0122 [29]	0.01–0.05
the base value corresponds to the average life expectancy of ≈ 82 years
HZ reactivation rate	η	0.05 [4,15,17]	0.0001–2.0
HZ recovery rate	ρ	52 [17]	46–58
the base value corresponds to the average infectious period of ≈ 7 days
Rate of HZ reactivation after loss of immunity following recovery from HZ	δ	0.01 [12,23]	0.00–0.10
Rate of loss of immunity to VZV after recovery from HZ	θ	4.0 [assumed]	0.00–12.0
the base value corresponds to immunity lasting 3 months on average
Relative VZV infectiousness of HZ	p	0.001 [10,17]	0.00–0.10

All rates in this table are per year. Note that β and p are used to define the force of infection (2).

ISSN: 1742-4682