Paediatric Virology and its interaction between basic science and clinical practice (Review)

Mammas, Ioannis N.; Greenough, Anne; Theodoridou, Maria; Kramvis, Anna; Rusan, Maria; Melidou, Angeliki; Korovessi, Paraskevi; Papaioannou, Georgia; Papatheodoropoulou, Alexia; Koutsaftiki, Chryssie; Liston, Maria; Sourvinos, George; Spandidos, Demetrios A.

Live-attenuated influenza vaccines (LAIV) have been used in certain European countries, such as UK and Finland, and in the USA and Canada for decades (60, 61) . In addition to their efficient mode of introduction as a nasal spray, in randomised clinical trials, they have been shown to provide better protective efficacy than inactivated influenza vaccines (IIV) in children, which are considered to be the main drivers of There are certain performance limitations, one of which is that previous influenza vaccination may modify the immune response after a repeated vaccination (60) . Further studies are warranted to determine the reasons for reduced VE. A recent systematic literature review did not find any evidence of the decreased efficacy of LAIV when administered during two consecutive seasons (67) . On the other hand, the findings of a study that evaluated the impact of repeated vaccination among health care workers were suggestive of decreased serological response among the highly vaccinated group (68) . Another consortium, Seasonal Influenza Vaccination Effectiveness II (SIVE II), is currently evaluating the safety and effectiveness of the LAIV programme in children (69) . The vaccination of healthy children has the potential to provide both direct protection to children, but also indirect protection to vulnerable groups in the general population. Further studies with large sample sizes and a greater number of people in the vaccine-naïve group and in groups with repeated vaccinations are required.