Objectives and methods: We conducted a prospective study in 2013 to compare the effectiveness and duration of protection of whole-cell versus acellular pertussis vaccines following the occurrence of pertussis clusters. Results: During seven school outbreaks, we identified 102 clinical cases of pertussis, including 10 cases biologically confirmed by Bordetella pertussis-specific PCR, among a cohort of 305 children in grades 2 through 6. The risk of pertussis among children vaccinated with an acellular vaccine alone was 1.6 (RR=1.6; 95% CI=1.1–2.5) times higher than among those vaccinated with a whole-cell vaccine or following a combined vaccination schedule. Conclusions: The limited duration of protection provided by the acellular vaccine supports the 2013 introduction of the pertussis booster at age six.