At weeks 2 , 4 , 8 , and 12 , Bravecto ( fluralaner ) flea-control efficacy in treated households was 99.2 % , 99.8 % , 99.8 % , and 99.9 % respectively , while Frontline ( fipronil ) efficacy was 94.1 % , 93.0 % , 96.0 % , and 97.3 % , respectively .