Evolución de la incidencia de tos ferina en la ciudad de Barcelona entre 1999 y 2011

[Acellular vaccines (DTPa/dTpa) against whooping cough, protection duration]

INTRODUCTION

An increase in whooping cough in most of the developed countries has been detected in the last decade.

OBJECTIVE

To determine whether the administration of dTpa vaccine instead of DTPa fifth dose is contributing to the appearance of these cases.

METHODS

A descriptive study based on cases of whooping cough reported during an epidemic period in the city of Alicante in the first 5 months of 2014. Only pertussis cases confirmed by PCR were included in the study, and only those vaccinated with 5 doses were included in the analysis of the period of protection.

RESULTS

A total of 104 cases of pertussis confirmed by PCR were reported, with 85 cases (82%) having had 5 doses of vaccine. The mean time and standard deviation (SD) of protection was 2.1±1.1 years with dTpa, and 5.1±1.5 years with DTPa (p<.001). In the protection, adjusted for age, it was observed that, after 3 years, only 47.6% of people vaccinated with dTpa were still protected, while people vaccinated with DTPa were 100% protected (P<.001).

CONCLUSIONS

This study found that people who were properly vaccinated against pertussis and received their last re-vaccination dose with dTpa had a shorter period of protection than those who were vaccinated with DTPa.

Evaluation of reported cases of pertussis: epidemiological study in a large city in Spain

We retrospectively analysed the incidence rate of reported cases of pertussis in Barcelona during 2009–2012 according to age, sex, type of medical centre and vaccination status. We included 748 confirmed or suspected cases, 613 (82.0 %) of which were confirmed by laboratory testing and the remaining 135 (18.0 %) by epidemiological evidence. The highest reported incidence of pertussis was amongst <1 year olds [96.1 per 100 000 person-years, 95 % confidence interval (CI): 84.3–109.1]. The majority of confirmed and suspected cases were reported in 2011 and 2012, and the total incidence (confirmed or suspected) was 6.3 (95 % CI: 5.6–6.9) and 4.2 (95 % CI: 3.6–4.7) per 100 000 person-years, respectively. Incidence increased significantly (P = 0.001) in 2011–2012 compared with 2009. Most confirmed cases occurred in children <1 year old (87.9 %). Cases were confirmed by real-time (RT)-PCR (87.5 %; 95 % CI: 81.3–87.6) and bacterial culture (13.7 %; 95 % CI: 11.0–17.1). We recommend performing RT-PCR in suspected cases with no epidemiological link to a confirmed case.

[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.