Source: Pediatrics | Vol:Vol. 132 | Page: 624
By: Atwell, Jessica E. ; Van Otterloo, Josh ; Zipprich, Jennifer
California reported 9,120 cases of pertussis in 2010, the highest number since 1947. While the waning immunity of the acellular vaccine is largely blamed for the resurgence, researchers analyzed nonmedical exemptions (NMEs) for children entering kindergarten from 2005 to 2010 to determine whether they also played a role. They found 39 statistically significant clusters of high NME rates and two statistically significant clusters of pertussis cases during the study period, determining that Census tracts within the NME clusters were 2.5 times more likely to be in a pertussis cluster. The researchers ultimately concluded that NME clusters may have contributed to the resurgence of pertussis in the state.