In the modified intention-to-treat analysis , similar efficacy was observed ( vaccine efficacy , 37.7 % , 41.1 % , and 75.8 % , respectively ) , and community-acquired pneumonia occurred in 747 persons in the PCV13 group and 787 persons in placebo group ( vaccine efficacy , 5.1 % ; 95 % CI , -5.1 to 14.2 ) .