Excess mortality in Italy: Should we care about low influenza vaccine uptake?

AIMS: The aims of this study were to explore 2015 mortality data further and to assess excess deaths' determinants.

METHODS: We analysed data from a large metropolitan area in the north of Italy, the city of Bologna. We took advantage of a comprehensive local-level database and merged three different data sources to analitically explore reported 2014-2015 excess mortality and its determinants. Effect estimates were derived from multivariable Poisson regression analysis, according to vaccination status and frailty index.

RESULTS: We report 9.8% excess mortality in 2015 compared to 2014, with seasonal and age distribution patterns in line with national figures. All-cause mortality in the elderly population is 36% higher (risk ratio [RR]=1.36, 95% confidence interval [CI] 1.27-1.45) in subjects not vaccinated against seasonal flu compared to vaccinated subjects, with risk of death for influenza or pneumonia being 43% higher (RR=1.43, 95% CI 1.02-2.00) in unvaccinated subjects.

CONCLUSIONS: Reported excess mortality's determinants in Italy should be further explored. Elderly subjects not vaccinated against the flu appear to have increased risk of all-cause and cause-specific mortality compared to vaccinated subjects after accounting for possible confounders. Our findings raise awareness of the need to promote immunisation against the flu among elder populations and offer insights to plan and implement effective public-health interventions.