To summarize the evidence from RCTs to investigate the effect of probiotics / prebiotics on the immune response of adult accept influenza vaccination.
Databases were searched from inception to July 2017. We used Cochrane Review risk-of-bias assessment tools of RCT for quality assessment. Our objective is seroprotection and seroconversion rate of the influenza vaccination influenced by probiotics / prebiotics.
A total of 20 RCTs comprising 1,979 adults were included in our systematic review. Nine RCTs including 623 participants were pooled through a meta-analysis. Participants who take probiotics / prebiotics showed a significant improvement in H1N1 seroprotection rate(OR= 1.83, 95% CI 1.19 - 2.82, p=0.006, I2=0%), in H3N2 seroprotection rate(OR= 2.85, 95% CI 1.59 -5.10, p<0.001, I2=0%) and in B strain seroconversion rate(OR= 2.11, 95% CI 1.38 - 3.21, p<0.001, I2=0%). In subgroup analysis according to intervention type, participants using probiotics had a significant better seroconversion rate in H3N2(OR=3.52, 95% CI 1.45 - 8.53, p= 0.005, I2= 63%). Meta-regression disclosed the effect of probiotics / prebiotics was significantly positive correlated with the duration of supplements on seroconversion rate for influenza B strain and seroconversion rate for influenza H1N1 strain. Subgroup analysis also showed that health elders supplemented with probiotics / prebiotics exhibited significant better response to all of the influenza strains than health adults and unhealthy elders.
This meta-analysis suggests that probiotics / prebiotics is effective to elevate the immunogenicity of seroconversion and seroprotection rate for adults inoculated with influenza vaccine, especially the health elders and longer treatment duration.