Risk factors for complications in hospitalized young infants presenting with uncomplicated pertussis

Hospitalisation of preterm infants with pertussis in the context of a maternal vaccination programme in England

AIMS

To assess whether preterm infants are at increased risk of pertussis infection and whether this increased following introduction of a maternal pertussis vaccination in England, while examining characteristics of infants associated with more severe disease.

METHODS

Infants aged <60 days admitted between 1 April 2009 and 31 March 2016 with a pertussis diagnosis code were extracted from Hospital Episode Statistics (HES) data. HES data were reconciled with existing surveillance systems to capture maternal vaccination status where available. Cases were compared preimplementation and postimplementation of the maternal programme with respect to demography, preterm or full-term birth and coinfection. Survival analysis was undertaken to assess the impact of variables on duration of hospital stay.

RESULTS

The proportion of hospitalised preterm infants (138/1309, 10.6%) was higher than population estimates (7.4%), increasing from 9.8% (83/847) to 12.1% (56/462) following implementation of the maternal programme. Longer duration of hospital stay was associated with prematurity, younger age, additional respiratory illnesses and mothers unvaccinated in pregnancy. Of 13 deaths, 5 were preterm (38.5%) and 11 (84.6%) were female. A larger proportion of full-term infants' (49/188, 26.1%) mothers had been vaccinated in pregnancy than preterm infants (7/49, 14.3%), with 14.3% of mothers of full-term cases vaccinated after 35 weeks.

CONCLUSIONS

Preterm infants are over-represented in hospitalised pertussis cases and have less benefit from the maternal pertussis vaccination programme in England due to reduced opportunity for maternal vaccination.

Trends in hospitalizations and resource utilization for pediatric pertussis

BACKGROUND AND OBJECTIVE

Pertussis is a serious and preventable childhood illness often necessitating hospitalization. The objective was to describe national trends in pediatric pertussis hospitalizations and resource utilization and factors associated with increased length of stay (LOS).

METHODS

This was a cross-sectional analysis of the 1997 to 2009 Healthcare Cost and Utilization Project Kids' Inpatient Databases. We examined pediatric hospitalizations of children (0-18 years) with a diagnosis of pertussis. Primary outcomes were hospitalizations, LOS, and charges. Weighted linear regression was used to evaluate trends in resource utilization. Multivariate logistic regression was used to determine factors associated with prolonged LOS.

RESULTS

Infants 0 to 6 months old accounted for nearly 90% of pediatric pertussis hospitalizations. Hospitalizations in public payers increased from 50% in 1997 to 67.4% in 2009 (P < .01). Among children with complex chronic conditions (CCCs), pertussis hospitalizations increased from 9.4% in 1997 to 16.8% in 2009 (P < .01). Mean LOS for pediatric pertussis hospitalizations decreased from 5.40 days in 1997 to 5.28 days in 2009 (P < .01), whereas those for children with CCCs increased from 8.86 days in 1997 to 9.25 days in 2009 (P < .01). Mean adjusted charges for pediatric pertussis hospitalizations rose from $14 520 in 1997 to $22 278 in 2009 (P < .01). For all study years, neonates and children with CCCs had greater odds of prolonged LOS.

CONCLUSIONS

Young infants and publicly insured patients account for a disproportionate number of pertussis-related hospitalizations. Patients with CCCs are increasingly contributing to hospitalizations and resource utilization attributable to pertussis. As new vaccine recommendations are implemented, targeted interventions are warranted to increase preventive efforts in these vulnerable populations.