Missed opportunities for simultaneous administration of the fourth dose of DTaP among children in the United States

Abstract Background Simultaneous administration of all age-appropriate doses of vaccines is an effective strategy for raising vaccination coverage. Vaccination coverage for ≥4 dose of DTaP (diphtheria, tetanus toxoids, and acellular pertussis vaccine) among children 19–35 months in the United States has not reached the Healthy People 2020 target of 90%. Risk factors for missed opportunities for simultaneous administration of the fourth dose of DTaP have not been investigated. Methods A missed opportunity for simultaneous administration of the fourth dose of DTaP is defined as the failure to administer an age-eligible fourth dose of DTaP, and during the same age-eligible period for the fourth dose of DTaP other recommended and age-appropriate doses of vaccines are given to children. This study used 2001–2014 National Immunization Survey data to describe the trend in missed opportunities for simultaneous administration of the fourth dose of DTaP from 2001 through 2014, assess the prevalence of children who missed opportunities for simultaneous administration of the fourth dose of DTaP by selected factors, and recognize significant risk factors for missed opportunities for simultaneous administration of the fourth dose of DTaP. Results From 2001 to 2014, the prevalence of missed opportunities for simultaneous administration of the fourth dose of DTaP among children 19–35 months in the United States ranged from 5.7% to 9.0%; across 13 factors considered, the prevalence of missed opportunities varied from 3.3% to 22.9%. Children who were late in receiving the first to third dose of DTaP had significantly higher prevalence of missed opportunities for simultaneous administration of the fourth dose of DTaP than children who received these doses on-time, with adjusted prevalence ratios for late vs. on-time of 1.7, 1.6, and 3.2, and all P-value  Conclusions Improving on-time vaccination of the third dose of DTaP could substantially reduce missed opportunities for simultaneous administration of the fourth dose of DTaP.