Joan A. Caylà

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 (82.0u200a%) of which were confirmed by laboratory testing and the remaining 135 (18.0u200a%) by epidemiological evidence. The highest reported incidence of pertussis was amongst <1 year olds [96.1 per 100,000 person-years, 95u200a% 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 (95u200a% CI: 5.6-6.9) and 4.2 (95u200a% CI: 3.6-4.7) per 100,000 person-years, respectively. Incidence increased significantly (Pu200a=u200a0.001) in 2011-2012 compared with 2009. Most confirmed cases occurred in children <1 year old (87.9u200a%). Cases were confirmed by real-time (RT)-PCR (87.5u200a%; 95u200a% CI: 81.3-87.6) and bacterial culture (13.7u200a%; 95u200a% CI: 11.0-17.1). We recommend performing RT-PCR in suspected cases with no epidemiological link to a confirmed case.

Outbreaks of hepatitis A associated with immigrants travelling to visit friends and relatives

We have read with interest the article by Purcell et al., who reported a cluster of hepatitis A cases in South East England. The investigation of this cluster did not identify any common exposure. In other studies, one of the most frequent reported risk factors is travel to countries with high disease endemicity. Immigrants often make trips that involve close contact with the local population and an increased risk of exposure to different diseases. In the last decade, Catalonia has received a large amount of immigrants from low income countries. Catalonia initiated a program of hepatitis AþB vaccination during 1998e1999 in preadolescents aged 11e12. This program has reduced exposure to the virus and has favoured the accumulation of a susceptible population not covered by the vaccination program. We made a descriptive epidemiological study to characterize index cases of hepatitis A outbreaks in Catalonia in 2001e2012 due to person-to-person transmission and to compare index cases in immigrants and indigenous people. Catalonia is an autonomous community in northwest Spain with a population of 7.5 million. The Statistical Institute of Catalonia (IDESCAT) estimates that 15% of the current population comes from other countries. A hepatitis A outbreak was defined as 2 associated cases with at least one microbiologically confirmed by determination of IgM antibodies. The index case of the outbreak was defined as the first case with onset of symptoms and/or diagnosed (IgM antibodies) and which, according to the epidemiological methods used, most probably began the transmission. In Catalonia, all suspected epidemic outbreaks must be notified to the epidemiological surveillance units (ESU) whose staff confirmed the outbreak and wrote a report on clinical and epidemiological characteristics. Index cases were identified by reviewing reports from each outbreak. Data on the index case was collected by ESU staff using a standardized questionnaire. The variables of the index cases collected were age, sex, country of origin (in the case of children the parents’ country of origin), the setting of the outbreak, visiting family, and men who have sex with men. Factors associated

Underdetection and underreporting of pertussis in children attended in primary health care centers: Do surveillance systems require improvement?

BACKGROUNDnPertussis is an underestimated disease. Several European countries have developed models to account for underreporting of pertussis. The aim of this study was to estimate pertussis underdetection and underreporting in pediatric patients attending primary health care centers (PHCCs).nnnMETHODSnWe reviewed clinical records of PHCCs in Barcelona in 2012. Factors associated with underdetection and underreporting were analyzed by logistic regression. Adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) were calculated.nnnRESULTSnWe included 3,505 children aged < 7 years (mean age, 34 u2009±u2009 20.7 months; range, 0-82 months) presenting with cough; 9.3% (326 out of 3,505) of patients also had ≥ 1 symptoms related to pertussis accompanied by cough for a duration ≥ 2 weeks. Of the 326 children receiving clinical criteria, only 31 (9.5%) were laboratory-confirmed and 6 (1.8%) were detected but not reported. There were 295 (90.5%) undetected suspected pertussis cases. Age ≥ 18 months (aOR, 8.51; 95% CI, 1.82-39.86), cyanosis (aOR, 6.71; 95% CI, 1.43-31.39), request for chest radiograph (aOR, 0.26; 95% CI, 0.07-0.99), and request for other laboratory tests (aOR, 5.39; 95% CI, 2.19-13.27) were associated with underdetection. Paroxysmal cough (aOR, 5.77; 95% CI, 1.05-31.76) and request for other laboratory tests (aOR, 2.91; 95% CI, 1.11-7.62) were associated with underreporting.nnnCONCLUSIONSnBoth underdetection and underreporting complicate the understanding of pertussis epidemiology. Correct assessment of pertussis symptoms and notification of cases must be improved to control pertussis.

Assessment of clinical symptoms in household contacts of confirmed pertussis cases

OBJECTIVESnWe assessed the value of the clinical symptoms included in the case definition of pertussis in household contacts of laboratory-confirmed cases.nnnMETHODSnA prospective epidemiological study was made in two Spanish regions. Household contacts were identified for each confirmed case reported during 2012 and 2013. Two clinical samples were taken to determine the presence or absence of Bordetella pertussis by culture or real-time PCR. Clinical variables, age and vaccination status were recorded. Positive and negative likelihood ratios (PLR, NLR) were estimated for each symptom.nnnRESULTSn2852 household contacts of 688 confirmed cases were reported. 178 household contacts with clinical symptoms were analyzed: 150 were laboratory confirmed and 28 were not. The clinical symptom with the highest PLR in comparison with the NLR was paroxysmal cough(PLR 4.76; 95% CI 1.91-11.87 and NLR 0.37; 95% CI 0.28-0.49). The contrast between the PLR and NLR was especially important for persons aged <18 years (PLR 7.08; 95% CI 1.10-45.74 and NLR 0.32; 95% CI 0.21-0.49).nnnCONCLUSIONSnThe clinical symptoms of pertussis are poor predictors of pertussis disease, independently of the vaccination status. Differences were observed between persons aged <18 years and adults. To adopt the appropriate treatment and control measures, rapid laboratory confirmation by PCR of all household contacts of confirmed cases who present any clinical symptoms compatible with pertussis should be recommended.