Exploring the potential public health benefits of universal influenza vaccine

Figures & data

Figure 1. Difference in symptomatic influenza cases (relative to baseline)

Figure 2. Epidemic curves with and without universal vaccine

Table 2. Key parameters in the model

		Range
Parameter		Minimum	Maximum	Reference
Coverage by age, years
6 months-17 years	68.8%	68.8%	85.9%	Adapted
18-49 years	21.6%	21.64%	27.0%/54.1%	from [31]
≥50 years	43.8%	43.8%	54.8%
Latent period, days	1.9	1	2
Infectious period, days	4.1	3	6
Asymptomatic rate	33%			[24-30]
Asymptomatic reduction in infectivity	50%
Symptomatic absenteeism	50%

Table 1. Vaccination coverage and averted influenza cases when total population coverage in Year 1 = 50%

Year 1		Years 2–4		Year 1	Year 2	Year 3	Year 4
Ratio of universal:seasonal influenza vaccine in 18 to 49-year-olds	Vaccine coverage of 18 to 49-year-olds	Vaccine protection of 18 to 49-year-olds	Vaccine protection of total population	Averted cases/100,000 of each population group
				Children 6 months to 17 years
0:100	27.1%	27.1%	50%	–	–	–	–
50:50	27.1%	40.7%^†	54.4%	−1,410	1,432	1,111	1,357
100:0	27.1%	54.2%^‡	58.8%	−2,468	2,255	2,418	2,500
				Adults 18–49 years
0:100	27.1%	27.1%	50%	–	–	–	–
50:50	27.1%	40.7%*	54.4%	−513.2	494.1	431.9	479.3
100:0	27.1%	54.2%**	58.8%	−963.4	853.5	891.0	905.5
				Adults ≥50 years
0:100	27.1%	27.1%	50%	–	–	–	–
50:50	27.1%	40.7%*	54.4%	−938.9	905.0	792.6	879.7
100:0	27.1%	54.2%**	58.8%	−1,760	1,572	1,639	1,667

*50% universal vaccine X 27.1% total vaccine given in Year 1, yields 13.6% universal vaccine coverage carried over into Years 2–4. This is added to the 27.1% seasonal vaccine given in Years 2–4 to yield a combined coverage of 40.7% in Years 2–4.

**100% universal vaccine X 27.1% total vaccine given in Year 1, yields 27.1% universal vaccine coverage carried over into Years 2–4. This is added to the 27.1% seasonal vaccine given in Years 2–4 to yield a combined coverage of 54.2% in Years 2–4.

Figure A1. Histogram of R0

Table A1. Vaccination coverage and averted influenza cases when total population coverage in Year 1 = 40%

Year 1		Years 2–4		Year 1	Year 2	Year 3	Year 4
Ratio of universal:seasonal influenza vaccine in 18 to 49-year-olds	Vaccine coverage of 18 to 49-year-olds	Vaccine protection of 18to 49-year-olds	Vaccine protection of total population	Averted cases/100,000 of each population group
				Children 6 months to 17 years
0:100	21.6%	21.6%	40%	–	–	–	–
50:50	21.6%	32.4%*	44.4%	−811.3	1,050	1,014	820.7
100:0	21.6%	43.2%**	48.8%	−2,018	2,135	1,923	2,232
				Adults 18–49 years
0:100	21.6%	21.6%	40%	–	–	–	–
50:50	21.6%	32.4%*	44.4%	−388.0	427.2	417.2	382.7
100:0	21.6%	43.2%**	48.8%	−867.8	854.3	801.5	873.5
				Adults ≥50 years
0:100	21.6%	21.6%	40%	–	–	–	–
50:50	21.6%	32.4%*	44.4%	−700.8	772.1	757.4	683.0
100:0	21.6%	43.2%**	48.8%	−1,563	1,545	1,453	1,575

*50% universal vaccine X 21.6% total vaccine given in Year 1, yields 10.8% universal vaccine coverage carried over into Years 2–4. This is added to the 21.6% seasonal vaccine given in Years 2–4 to yield a combined coverage of 32.4% in Years 2–4.

**100% universal vaccine X 21.6% total vaccine given in Year 1, yields 21.6% universal vaccine coverage carried over into Years 2–4. This is added to the 21.6% seasonal vaccine given in Years 2–4 to yield a combined coverage of 43.2% in Years 2–4.

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