Table 2.

Dependence of antigenic diversity structure in the steady coexistence on the transmission rates. Other parameter values are immunity period = 3 years, transmission rate of single infections (β ₁) = 1.0, and infectious period = 2 days; hence R ₀ = 2.0 for single infection; ten indistinguishable strains (n = 10) are assumed to cocirculate while three models are considered in which the most complex coinfections are of multiplicity m = 2,3, 4 strains, respectively.

m	β 2	β 3	β 4	ϕ	p	p 1	p 2	p 3	p 4
4	0.5	0.0	0.0	0.75	9.535 × 10−4	9.502 × 10−4	3.263 × 10−6	7.469 × 10−9	1.664 × 10−11
		0.4	0.0	0.75	9.535 × 10−4	9.502 × 10−4	3.274 × 10−6	1.253 × 10−8	3.019 × 10−11
		0.4	0.4	0.75	9.535 × 10−4	9.502 × 10−4	3.274 × 10−6	1.256 × 10−8	5.038 × 10−11
		0.4	0.4	0.0$	9.487 × 10−4	9.455 × 10−4	3.214 × 10−6	1.214 × 10−8	4.826 × 10−11
	0.75	0.0	0.0	0.38	9.535 × 10−4	9.470 × 10−4	6.444 × 10−6	1.714 × 10−8	6.170 × 10−11
		0.6	0.0	0.38	9.536 × 10−4	9.470 × 10−4	6.529 × 10−6	4.349 × 10−8	1.328 × 10−10
		0.6	0.4	0.38	9.536 × 10−4	9.470 × 10−4	6.534 × 10−6	4.369 × 10−8	2.218 × 10−10
		0.6	0.4	0.0$	9.487 × 10−4	9.423 × 10−4	6.386 × 10−6	4.209 × 10−8	2.117 × 10−10
3	0.5	0.0	—	0.75	9.535 × 10−4	9.502 × 10−4	3.263 × 10−6	7.478 × 10−9	—
		0.4	—	0.75	9.535 × 10−4	9.502 × 10−4	3.274 × 10−6	1.249 × 10−8	—
		0.4	—	0.0$	9.486 × 10−4	9.454 × 10−4	3.213 × 10−6	1.216 × 10−8	—
2	0.5	—	—	0.75	9.535 × 10−4	9.502 × 10−4	3.256 × 10−6	—	—
		—	—	0.0$	9.486 × 10−4	9.454 × 10−4	3.223 × 10−6	—	—

^$These coexistence equilibria are unstable.