The cost-effectiveness of influenza vaccination of pregnant woman in the South African public healthcare setting

Abstract

Background: International analyses suggest that routine maternal vaccination with seasonal trivalent influenza vaccine is cost-effective, but few studies have been done in middle- to low- income countries. Method: A decision-tree analysis was modelled for the South African public healthcare setting over one year from a payer's perspective. Direct medical costs and consequences were obtained from published literature. Incremental cost effectiveness ratios (ICERs) and univariate sensitivity analyses were then measured. Discounting was excluded due to the seasonality of influenza, limiting the time horizon to a one year period. Findings: The model predicted that to avert influenza-associated hospitalisations amongst pregnant women and their infants less than six months of age, vaccination of pregnant women was not cost-effective. This was irrespective of whether the universal vaccination or HIV-targeted approach was used. A base model simulating 100% vaccine uptake predicted that seasonal vaccination of 100,000 pregnant women results in an estimated net cost of R69,118,114.05 per neonatal influenza-associated hospitalisation averted. Similarly, the model suggested that vaccinating 100,000 pregnant women would cost R1,197,779.79 per maternal hospitalisation averted. Univariate sensitivity analyses reinforced that influenza vaccination of pregnant women was not cost-effective, except when lower incidence of maternal influenzaassociated hospitalisations associated with antenatal influenza vaccination were simulated where the targeted approach became dominant. The latter analysis predicted savings of R770,530.86 per maternal influenza-associated hospitalisation averted. Interpretation: The ICERs suggest that influenza vaccination amongst pregnant women is not cost-effective in the South African public healthcare sector compared to no vaccination, with respect to averting influenza-associated hospitalisations amongst pregnant women and their infants less than six months of age. However, these estimates should be re-evaluated, pending vaccine effectiveness studies of higher methodological quality for low- and middle- income countries and using cost inputs relevant to South African public healthcare setting. This analysis may provide preliminary information regarding the upscaling of influenza vaccination amongst pregnant women as a priority in the constraints of a limited healthcare budget and careful consideration is required regarding vaccine mobilisation amongst pregnant women.