Vaccines for preventing influenza in healthy children

Abstract

Analysis 1.1. Comparison 1 Live vaccine versus placebo or no intervention (RCTs by age group), Outcome 1 Influenza. Analysis 1.2. Comparison 1 Live vaccine versus placebo or no intervention (RCTs by age group), Outcome 2 Influenza-like

Vaccines in the Prevention of Viral Pneumonia

“…A meta-analysis of nine randomized controlled trials compared LAIV to placebo demonstrated a relative efficacy of 77% against antigenically similar strains and 72% efficacy regardless of antigenic similarity, whilst comparison with TIV showed that 46% fewer children experienced influenza illness 33 . Other studies have also showed LAIV to consistently provide a higher level of protection in children when compared to inactivated vaccines or placebo [34][35][36] . Regarding other vaccine types, a Cochrane review in children aged 6 months to 2 years of age showed inactivated trivalent influenza vaccine is not significantly more efficacious than placebo 34 .…”

“…Other studies have also showed LAIV to consistently provide a higher level of protection in children when compared to inactivated vaccines or placebo [34][35][36] . Regarding other vaccine types, a Cochrane review in children aged 6 months to 2 years of age showed inactivated trivalent influenza vaccine is not significantly more efficacious than placebo 34 . However a 2011 randomised controlled trial involving 4707 children aged 6 to 72 months (1941 vaccinated) showed that the adjuvant influenza vaccine (MF59 adjuvant trivalent vaccine) was significantly more effective than control or lone trivalent vaccine at preventing influenza like illness 37 Interestingly when given to children (age 6-15 years) the TIV vaccine has been associated with an increase in the rates of noninfluenza respiratory virus infection 38 .…”

Live attenuated influenza vaccine for children

“…Other outcomes reported in clinical studies include the impact on school absenteeism, prescriptions and consultation rates. 6 Market authorisation may be based on comparative immunogenicity data (e.g. for authorisation of a quadrivalent vaccine for which a trivalent vaccine is already authorised).…”

A review of the changes to the licensing of influenza vaccines in Europe

“…For children younger than 3 years, there is inconsistent evidence on the efficacy and effectiveness of seasonal inactivated vaccines 24, 25. Efficacy in this age group cannot be assumed for existing vaccines and cannot therefore be deduced from comparative immunogenicity studies.…”

“…Hence, the proposed guideline requires applicants to conduct randomized controlled trials with clinical endpoints in order to conclude efficacy for children aged 6 months to 3 years. For children between the ages of 3–6 years, there is some evidence to support efficacy of inactivated influenza vaccines, albeit being moderate 24, 25, 26. Yet the proposed guideline states that as the proportion of children up to the age of approximately 9 years who are immunologically primed is thought to be variable, efficacy can be deduced from demonstrating a non‐inferior immune response to the youngest children for whom efficacy against clinical endpoints should have been demonstrated.…”