Table 2 Stratifications of the impact ratios (ρ)
From: How can the public health impact of vaccination be estimated?
No stratification: Vaccine impact does not vary between vaccination activities or birth cohorts in a population. | Stratification by activity type: Vaccine impact varies between RV and CV but does not vary across birth cohorts. |
\(\rho = \frac {D_{R} + D_{C}}{\text {FVP}_{R} + \text {FVP}_{C}}\) | RV: \(\rho _{R} = \frac {D_{R}}{\text {FVP}_{R}}\) and CV: \(\rho _{C} = \frac {D_{C}}{\text {FVP}_{C}}\) |
Stratification by birth cohort: Vaccine impact varies across birth cohorts in a population but does not vary between vaccination activities. | Stratification by activity type and birth cohort: Vaccine impact varies between vaccination activities and birth cohorts. |
\(\rho (k) = \frac {D(k)}{\text {FVP}(k)}\) | RV: \(\rho _{R}(k) = \frac { D_{R}(k)}{\text {FVP}_{R}(k)}\) and CV: \(\rho _{C}(k) = \frac { D_{C}(k)}{\text {FVP}_{C}(k)}\) |