PhD defence Pieter de Boer

Cost-effectiveness of vaccination strategies to protect older adults: focus on herpes zoster and influenza

Older adults are at increased risk of complications and death from infectious diseases. Vaccination can reduce the disease burden, but healthcare budgets are limited. The thesis of Pieter de Boer deals with the costs and effects of different vaccination strategies against two diseases with a considerable disease burden among older adults, i.e. shingles and influenza.Currently, two vaccines against shingles are available; a live-attenuated vaccine and a recombinant vaccine. Using mathematical modelling, vaccination of older adults with the recombinant vaccine was estimated to prevent a considerably higher disease burden than vaccination with the live-attenuated vaccine, particularly amongst those aged 70 years and older. However, a reduction of the vaccine price compared to the list price is needed to achieve favorable cost-effectiveness. Concerning influenza, the cost-effectiveness of a new quadrivalent vaccine was assessed. This vaccine contains antigens of a second B virus strain compared to the traditional trivalent vaccine. Modelling indicates that replacing the trivalent vaccine by the quadrivalent vaccine could be cost-effective in high-income countries, but in developing countries the extension of the vaccination coverage with the trivalent vaccine may be prioritized. Finally, the cost-effectiveness of an influenza vaccination programme for children was studied. Vaccination of children will indirectly protect older adults by reducing transmission. Indeed, dynamic modelling suggests that vaccination of children would reduce the disease burden in all age groups, and would be cost-saving. However, there are concerns that flu vaccination of children may also lead to large epidemics in individual seasons.

Promotores Prof.dr. M.J. Postma and Prof.dr. J.C. Wilschut