Vaccine-preventable disease (VPD) surveillance should be a priority throughout the world. In Italy, however, there is limited attention to the epidemiology of VPDs, with the consequence that their incidence is largely underestimated. Although notification of vaccine-preventable diseases is mandatory, very often the etiologic agents causing VPDs are not identified the etiological agents causing the major and most severe infectious diseases in childhood. Several reasons underlie the underestimation. For example, not having a good surveillance system does not allow us to organize a sustainable prevention project for example based on on the introduction of new vaccinations. For example the limited use of low-cost high-sensitivity techniques such as real-time PCR, which could, if more widely used, improve pathogen identification with 3 times the sensitivity of standard cultural methods. Therefore, the idea of this multicenter, biological sample study is to take advantage of the regional pediatric network with the goal of improving VPD surveillance and increase awareness of the importance of surveillance of preventable diseases with the vaccine within the pediatric network.

Inclusion Criteria:

• Subjects aged 0-18 years with infectious disease (bacterial or viral) diagnosed by molecular techniques at the AOU Meyer Immunology Laboratory
• Obtaining informed consent

Exclusion Criteria:

• Individuals with concomitant diseases such as cystic fibrosis, known immunodeficiency, or with infection suspected nosocomial (hospitalization or hospital admission within 15 days prior to the onset of symptoms) will be excluded from the study