A cost-utility analysis of antenatal screening to prevent congenital rubella syndrome

Presenter: Anna Lugnér, RIVM

Abstract

Most infectious diseases included in the National Immunization Programme (NIP) have become very rare in the Netherlands, except in the regions with low vaccination coverage (low vaccination coverage regions – LVR) where recently epidemics of rubella (2004/2005) and mumps (2007/2008) have taken place. In these regions, people often reject participation in the NIP because of religious reasons. These regions may hinder the otherwise successful control of vaccine preventable infectious diseases. During the rubella epidemic in 2004/2005, 33 pregnant women living in LVR were notified with rubella infection. A pregnant woman who is infected with rubella has a high risk of miscarriage or giving birth to a child with congenital rubella syndrome (CRS). This syndrome entails different kinds of defects, including deafness, heart defects, and defects on the central nervous system, and multiple defects are also frequent. Of the 33 infected women two suffered from spontaneous abortions and nine babies were born with different kinds of CRS defects. A second group women vulnerable to rubella infection due to lack of vaccination is first generation non-western immigrant women. This study presents a cost-utility analysis of a screening and vaccination programme for rubella in pregnant women in the Netherlands. The analysis focuses on a three scenarios: (1) screening of all pregnant women in LVR; (2) screening of non-vaccinated pregnant women in LVR; and (3) screening of all non-vaccinated pregnant women in the Netherlands. We estimate the cost-effectiveness during a time span of 16 years with two rubella outbreaks. This outbreak frequency is based on the interval between the two last outbreaks (8 years). In the years between outbreaks we estimate that one case of rubella infection in a pregnant woman occurs and that the probability for a CRS-case is 1/3. Programme costs are the costs of the screening test, which takes place together with the regular screening at about 12 weeks of pregnancy, and the inoculation measles-mumps-rubella vaccination for the women who accept the post partum vaccination if they did not have any protection against rubella. The CRS-complications observed from the 2004/2005 epidemic are used to estimate the average saved cost and average quality-adjusted life year (QALY)-gained for preventing one unspecified CRS case. A CRS case can only be prevented in a subsequent pregnancy if vaccination is accepted and effective. The first two factors differ between the groups of non-vaccinated women and we therefore adjusted the potentially saved costs and QALY-gained for these factors in the different scenarios. The results show that a screening and vaccination programme would be cost-effective (below EUR20,000) if targeted at non-vaccinated women in the LVR (scenario 2). The other two scenarios would not be cost-effective to implement. We conclude that with the current knowledge on the probabilities that a non-vaccinated woman would accept vaccination, only screening of high-risk group (non-vaccinated in LVR) would be cost-effective.