Vaccine preventable invasive bacterial diseases in Italy: A comparison between the national surveillance system and recorded hospitalizations, 2007-2016

Patrizio Pezzotti; Stefania Bellino; Flavia Riccardo; Francesca Lucaroni; Marina Cerquetti; Annalisa Pantosti; Giovanni Rezza; Paola Stefanelli

doi:10.1016/j.vaccine.2018.11.047

Vaccine preventable invasive bacterial diseases in Italy: A comparison between the national surveillance system and recorded hospitalizations, 2007-2016

Vaccine. 2019 Jan 3;37(1):41-48. doi: 10.1016/j.vaccine.2018.11.047. Epub 2018 Nov 23.

Authors

Patrizio Pezzotti¹, Stefania Bellino², Flavia Riccardo², Francesca Lucaroni³, Marina Cerquetti², Annalisa Pantosti², Giovanni Rezza², Paola Stefanelli⁴

Affiliations

¹ Department of Infectious Diseases, Italian National Institute of Health (Istituto Superiore di Sanità, ISS), Rome, Italy. Electronic address: patrizio.pezzotti@iss.it.
² Department of Infectious Diseases, Italian National Institute of Health (Istituto Superiore di Sanità, ISS), Rome, Italy.
³ Tor Vergata University, Rome, Italy.
⁴ Department of Infectious Diseases, Italian National Institute of Health (Istituto Superiore di Sanità, ISS), Rome, Italy. Electronic address: paola.stefanelli@iss.it.

PMID: 30478004
DOI: 10.1016/j.vaccine.2018.11.047

Abstract

Background: Vaccine-preventable invasive bacterial diseases (IBDs) caused by Neisseria meningitidis (Nm), Streptococcus pneumoniae (Sp), and Haemophilus influenzae (Hi) have been notified in Italy since 2007 without assessing reporting completeness.

Methods: Our study compared the number of cases of IBDs identified from the Italian Hospital Discharge Records (HDRs), using specific diagnostic ICD-9-CM codes, with those notified to the National Surveillance System (NSS) from 2007 to 2016. A multinomial logistic regression model was used to impute the aetiology of all discharges with a diagnosis of unspecified bacterial meningitis.

Results: Over a 10-year period, 14,243 hospital discharges with diagnosis of IBD were estimated in Italy (12,671 with specified aetiology and 1,572 with imputed aetiology). Among those, 2,513 (17.6%) were caused by Nm, 10,441 (73.3%) by Sp, and 1289 (9.1%) by Hi. Most invasive meningococcal diseases were coded as meningitis (72.3%), while Hi and Sp were more frequently coded as septicaemia (51.6% and 60.4%, respectively). The highest mean annual incidence rate was found for IBD caused by Sp (1.74 per 100,000), followed by Nm (0.42 per 100,000) and by Hi (0.21 per 100,000). Comparing NSS with HDR data, we found an initially high underreporting of all IBDs, and particularly for Hi. Data from the two systems overlapped in more recent years, due to an improved reporting completeness. The increasing IBD incidence observed in NSS data was not confirmed by HDR data trends, although with pathogen-related differences with Hi cases rising in both data sources, suggesting that is mainly due to an improved disease notification rather than to a true incidence increase.

Conclusions: Comparing surveillance data with other data sources is useful to better interpret observed trends of notifiable diseases.

Keywords: Haemophilus influenzae; Hospital discharge records; Invasive bacterial disease; National surveillance system; Neisseria meningitidis; Streptococcus pneumoniae.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Bacterial Infections / epidemiology*
Child
Child, Preschool
Epidemiological Monitoring*
Female
Haemophilus Infections / epidemiology
Hospital Records / statistics & numerical data*
Hospitalization / statistics & numerical data*
Humans
Incidence
Infant
Infant, Newborn
Italy / epidemiology
Male
Meningitis, Haemophilus / epidemiology
Meningitis, Meningococcal / epidemiology
Meningitis, Pneumococcal / epidemiology
Meningococcal Infections / epidemiology
Middle Aged
Patient Discharge / statistics & numerical data
Regression Analysis
Young Adult