Undervaccination – not receiving all recommended vaccinations or not being vaccinated according to the Advisory Committee on Immunization Practices schedule – results in an increased risk for whooping cough in children 3 to 36 months of age, according to a new Kaiser Permanente study. The study was published today in JAMA Pediatrics. In 2012, the United States experienced its largest whooping cough outbreak in 50 years.
Kaiser Permanente researchers used the Vaccine Safety Datalink – a collaborative effort among the Centers for Disease Control and Prevention and eight managed care organizations – in this study to analyze the immunization records of 323,247 children born between 2004 and 2008. Seventy-two patients with laboratory-confirmed cases of pertussis, commonly referred to as whooping cough, from this group were compared to four times as many children of the same age and gender who were not infected with whooping cough.
The diptheria, tetanus toxoids, and acelluar pertussis (DTaP) vaccine protects against whooping cough. It is given in a series to children at two months, four months, six months and 15-18 months of age and as a booster before kindergarten.
Of the 72 whooping cough patients in this study,16 percent were hospitalized and 47 percent were undervaccinated for the DTaP vaccine when the infection was diagnosed compared to 22 percent of patients who were not infected. Undervaccination was defined as missing any of the four scheduled DTaP vaccine doses. Children undervaccinated for three or four doses were more than 18 and 28 times as likely to have been diagnosed with whooping cough than children who were vaccinated according to ACIP immunization guidelines.