Vaccination coverage in Italian children and antimicrobial resistance: an ecological analysis

Background: Although a general consensus that vaccines could be a complementary strategy against antimicrobial resistance (AMR), there is still the need for studies investigating the relationship between childhood vaccination coverage and AMR proportions in the overall population. Methods: We performed an ecological analysis of available Italian data (vaccination coverages, AMR proportions, number of isolates tested, and antibiotic use) to evaluate the relationships between vaccination coverages in children and AMR proportions in the last 2 decades. Results: After adjusting for covariates, we showed that AMR proportions decreased with increasing vaccination coverages, especially for some combinations of vaccines, pathogens, and antimicrobials. Vaccination coverages for pertussis, diphtheria, and tetanus were inversely related to proportions of E. coli resistant to fluoroquinolones and third generation cephalosporins, K. pneumoniae resistant to carbapenems and third generation cephalosporins, and P. aeruginosa resistant to piperacillin and tazobactam. Polio vaccination coverage was inversely related to proportions of E. coli and K. pneumoniae resistant to third generation cephalosporins. Conclusions: These results, however, should be interpreted cautiously due to the ecological nature of our analysis. For this reason, further studies designed ad hoc should be encouraged to measure the impact of increasing childhood vaccination coverage on AMR.