Underreporting of congenital rubella in Italy, 2010-2014

In accordance with the goals of the World Health Organization Regional Committee for Europe, the Italian national Measles and Rubella Elimination Plan 2010-2015 aimed to reduce the incidence of congenital rubella cases to <1 case/100,000 live births by 2015. In Italy, a passive national surveillance system for congenital rubella and rubella in pregnancy is active since 2005. We estimated the degree of underreporting of congenital rubella, performing a capture-recapture analysis of cases detected through two independent sources: the national surveillance system and the national hospital discharge database, in the years 2010-2014. We found that 6 out of 11 cases tracked in the retrospective case-finding from hospital registries had not been notified to the surveillance system, and we estimated a degree of underreporting of 53% for the period 2010-2014. This approach showed to be simple to perform, repeatable, and effective.

In order to reduce underreporting, some actions aimed at strengthening surveillance procedures are needed. The adoption on a routine basis of the review of hospital discharge registries for case-finding, monthly zero-reporting, and actions to train and sensitize all the specialists involved in the care of pregnant women and the newborns to notification procedures are recommended. What is Known • In Italy, the incidence of congenital rubella was below the WHO target of 1/100,000 live births in 2005-2015, except for two peaks in 2008 and 2012 (5 and 4/100,000, respectively). • Further efforts are required to improve congenital rubella surveillance so that it is more sensitive and specific. The WHO proposes retrospective case-finding from hospital records as an alternative approach to detect infants with congenital rubella. What is New • Underreporting of congenital rubella in Italy was 53% in 2010-2014. • Hospital discharge registries resulted to be an appropriate source to detect congenital rubella cases.