Table 3 Transmission model parameters

N₀

Initial population size

Varied (50–10,000,000)

NA

\(\bar{\alpha }\)

Mean birth rate

Varied annually around a mean of 0.000565 camel⁻¹ day⁻¹ based on initial population size.

Estimates of 45.2% annual fecundity in KSA⁴⁶ taken together with assumptions that 90% of the population are female due to high male removal rate¹⁹ and that 50% of the female population are of reproductive age¹⁹

β

Effective contact rate

0.1–1.0 camel⁻¹ day⁻¹

Calibrated to our FoI estimates from age-stratified seroprevalence data

γ

Rate of recovery from infection

1/14 days

δ

Strength of seasonality of births

1 (0, 0.5 also considered)

¹⁹ see “Births” in Methods.

σ

Rate of waning of complete immunity following infection

1/30 days, 1/90 days (scenario with no complete immunity also considered)

NA

λ₁

Rate at which susceptible animals become infected, equal to \({{\rm{\beta }}}\frac{{{{\rm{I}}}}_{1}+{{\rm{r}}}{{{\rm{I}}}}_{2}}{{{\rm{N}}}}\)

0.1–3.0 calibrated by varying β

Our estimates from age-stratified seroprevalence data

ω

Rate of waning of mAbs

0.0136 day⁻¹

Our estimates from age-stratified seroprevalence data

μ₁

Daily mortality rate of camels <=2 yrs

0.0011 camel⁻¹ day⁻¹

Within the ranges described in ref. ⁴⁶ but exact value set to balance mean birth-rate

μ₂

Daily mortality rate of camels aged >2 yrs

0.00036 camel⁻¹ day⁻¹

Within the ranges described in ref. ⁴⁶ but exact value set to balance mean birth-rate

φ

Susceptibility to reinfection relative to first infection

0.75 (0–1 considered)

NA

r

Infectiousness of reinfections relative to first infections

0.01, 0.50

⁶ see “Immunity” in Methods.

p

Probability of being born with mAbs

the fraction of adults >4 yrs old who have been infected previously at the time of the birth

NA