Waning and less effective acellular whooping cough vaccines likely contributed to the 2010 California whooping cough outbreak, according to researchers from the Kaiser Permanente Vaccine Study Center.
In a large, retrospective study, using a new methodology that controls for seasonality, researchers did not find evidence of an increased risk of Guillan-Barre Syndrome (GBS) in the six week period after vaccination -- with any vaccine, including influenza.