Epidemiología de las hospitalizaciones atribuibles a infección por Bordetella pertussis en población general en España (1999-2005)

Paediatric hospitalizations due to whooping cough in Spain (1997-2017)

This epidemiological survey estimates the burden of whooping cough in infants up to 12 months old in Spain during a twenty-one-year period (1997-2017). The survey was conducted by reviewing data from the Spanish Surveillance System for Hospital Data. All hospitalizations due to whooping cough for infants, reported during the 1997-2017 period, were analysed. Codes were selected from the International Classification of Diseases, 9th Revision, Clinical Modification diagnosis codes 033.0-033.9. To explore the latest national outbreak and the implementation of vaccination in pregnant women, analyses were stratified to compare the following periods: 1997-2010, 2011-2015 and 2016-2017. A total of 13,352 hospital discharges for whooping cough in infants up to 12 months old were reported. A total of 6850 discharges in the period 1997-2010, 5271 in the period 2011-2015 and 1231 in 2016-2017 were identified. The annual hospitalization rate prior to 2011 was 131.02 cases per 100,000 infants; in 2011-2015, the rate was significantly higher (250.13 cases per 100,000 infants) and in 2016-2017 it decreased (157.69 cases per 100,000 infants). Most of the cases (n = 11,446) occurred in infants under 4 months of age, with hospitalization rates of 328.80, 670.81 and 385.84 cases per 100,000 infants up to 4 months of age in the periods 1997-2010, 2011-2015 and 2016-17, respectively. Thirty-four deaths occurred in the period 1997-2010, 36 in the period 2011-2015 and 4 in 2016-2017. All of the deaths occurred in infants under 4 months old. The case fatality rate did not vary significantly across the study periods. Whooping cough infections concentrate in infants up to 4 months of age in Spain. Public health measures such as vaccination of pregnant women, caregivers, health care professionals and relatives, especially young parents, could reduce the hospitalization burden during the current outbreak.

[Hospitalization due to whooping cough in Spain (1997-2011)]

INTRODUCTION

Pertussis incidence has increased in recent years in countries with high vaccination coverage. The aim of this study was to determine the health impact of pertussis in Spain in the period 1997-2011 in relation to hospitalizations, mortality, and associated costs.

METHODS

We retrospectively analyzed hospital discharges included in the Minimum Data Set (MDS) in Spain for the period 1997-2011, with a primary or secondary diagnosis related to pertussis. We calculated incidence rates of hospitalization for pertussis (per 100,000) per year, by age group and by Autonomous Region, along with the mortality and lethality rates.

RESULTS

A total of 8,331 hospital discharges with a diagnosis of pertussis were recorded in Spain between 1997 and 2011. The overall incidence of pertussis hospitalizations was 1.3 cases per 100,000 inhabitants. The large majority (92%) of hospitalizations occurred in children under one year of age, with an incidence of 115.2 hospitalizations per 100,000. There were 47 deaths, 37 (79%) in the group of children under 1 year and 6 (13%) in the group older than 65 years. The estimated cost of hospitalization for pertussis was 1,841 euros.

CONCLUSION

The epidemiology of severe cases of pertussis, and its clinical and economic impact, confirms the need to modify the vaccination strategies for Spain to achieve more effective control in the most vulnerable groups.