Joan Batalla

Impact and effectiveness of a mass hepatitis A vaccination programme of preadolescents seven years after introduction

AIM To investigate the impact of a mass hepatitis A vaccination programme in preadolescents seven years after introduction in terms of its effectiveness and the prevented fraction. SETTING The age distribution of notified cases and incidence rates in Catalonia (Spain) in the periods before (1992-1998) and after (1999-2005) introduction of the vaccination programme were compared. MAIN RESULTS The incidence rates in the whole population were 5.51 per 100,000 person-years in the 1992-1998 period and 2.98 in the 1999-2005 period. The rate reduction in the 10-19 years age group was 72.43% and was more than 45% in the 5-9 years and 20-29 years age groups. The effectiveness of the vaccination programme was 99.04 (95% CI: 93.11-99.88) and the prevented fraction in the 12-19 years age group was 90.13% (95% CI: 84.47-90.89). CONCLUSIONS The universal vaccination programme of preadolescents has had an important impact on hepatitis A in Catalonia, not only in vaccinated cohorts but also in non-vaccinated age groups due to a herd immunity effect.

Parental knowledge of paediatric vaccination.

BackgroundAlthough routine vaccination is a major tool in the primary prevention of some infectious diseases, there is some reluctance in a proportion of the population. Negative parental perceptions of vaccination are an important barrier to paediatric vaccination. The aim of this study was to investigate parental knowledge of paediatric vaccines and vaccination in Catalonia.MethodsA retrospective, cross-sectional study was carried out in children aged < 3 years recruited by random sampling from municipal districts of all health regions of Catalonia. The total sample was 630 children. Parents completed a standard questionnaire for each child, which included vaccination coverage and knowledge about vaccination. The level of knowledge of vaccination was scored according to parental answers.ResultsAn association was observed between greater vaccination coverage of the 4:4:4:3:1 schedule (defined as: 4 DTPa/w doses, 4 Hib doses, 4 OPV doses, 3 MenC doses and 1 MMR dose) and maternal age >30 years (OR: 2.30; 95% CI: 1.20–4.43) and with a knowledge of vaccination score greater than the mean (OR: 0.45; 95% CI: 0.28–0.72). The score increased with maternal educational level and in parents of vaccinated children.A total of 20.47% of parents stated that vaccines could have undesirable consequences for their children. Of these, 23.26% had no specific information and 17.83% stated that vaccines can cause adverse reactions and the same percentage stated that vaccines cause allergies and asthma.ConclusionHigher vaccination coverage is associated with older maternal age and greater knowledge of vaccination.Vaccination coverage could be raised by improving information on vaccines and vaccination.

Epidemiology of pertussis in a country with high vaccination coverage

INTRODUCTION Pertussis has been a preventable disease in Catalonia since 1965, but the annual number of cases remains high. The aim of this study was to analyze the epidemiology of pertussis in Catalonia and its implications for control purposes. METHODS An epidemiological study was carried out in Catalonia between 2004 and 2008. Pertussis cases reported to the Department of Health were collected and disease reports were filled out with the case information. Incidence rates, rate ratios (RR) and their 95% confidence intervals (CI) were calculated. RESULTS 963 cases were reported: 555 (57.6%) were confirmed and 408 (42.4%) were suspected cases. The reported incidence rate was 2.01 × 10(-5) person years in 2004 and 4.34 in 2008. The biggest increase in cases between 2004 and 2008 was observed in the ≥35 years age group (RR: 6.98; 95%CI: 2.11-36.36). 303 (31.5%) patients were hospitalized, of whom 93.7% were aged <1 year. Clinical differences were observed in paroxysmal cough (83.8% in suspected and 76.4% in confirmed cases, p=0.005), posttussive vomiting (47.1% and 36.1%, respectively, p=0.001), apnoea (13.7% and 21.3%, respectively, p=0.003) and fever (20.1% and 12.4%, respectively, p=0.001). CONCLUSION Pertussis incidence rates increased during the study period, with the greatest increase occurring in the ≥35 years age group. A booster dose of vaccine in young people could reduce the circulation of B. pertussis in adolescents and adults and indirectly reduce the incidence in children.

Mumps vaccine effectiveness in highly immunized populations.

The aim of the study was to investigate effectiveness of mumps MMR component in communities with high MMR coverage. Outbreak-related cases of mumps born between 1995 and 2005 notified to Navarre and Catalonia public health services during the period 2005-2007 were studied. Vaccine effectiveness (VE) and their 95%CI were calculated using the screening method. Of 47 confirmed, 85.1% immunized with at least one dose (1MMR) and 44.9% with two (2MMR). Estimated VE was 85.4% (95%CI: 67.3-93.4) for 1MMR and 88.5% (95%CI: 78.1-93.9) for 2MMR. High 2MMR coverage, improved confirmation techniques and further VE studies with all confirmed cases are needed to prevent further outbreaks.

Effectiveness of 7-valent pneumococcal conjugate vaccine in the prevention of invasive pneumococcal disease in children aged 7-59 months. A matched case-control study.

The aim of this study was to evaluate the effectiveness of the administration of the 7-valent pneumococcal conjugate vaccine in a region with an intermediate vaccination coverage. A matched case-control study was carried out in children aged 7-59 months with invasive pneumococcal disease (IPD) admitted to two university hospitals in Catalonia. Three controls matched for hospital, age, sex, date of hospitalization and underlying disease were selected for each case. Information on the vaccination status of cases and controls was obtained from the vaccination card, the childs health card, the hospital medical record or the vaccination register of the primary healthcare center where the child was attended for non-severe conditions. A conditional logistic regression analysis was made to control for the effect of possible confounding variables. The adjusted vaccination effectiveness of the complete vaccination schedule (3 doses at 2, 4 and 6 months and a fourth dose at 15 months, 2 doses at least two months apart in children aged 12-23 months or a single dose in children aged >24 months) in preventing IPD caused by vaccine serotypes was 93.7% (95% CI 51.8-99.2). It was not effective in preventing cases caused by non-vaccine serotypes. The results of this study carried out in a population with intermediate vaccination coverage confirm those of other observational studies showing high levels of effectiveness of routine 7-valent pneumococcal conjugate vaccination.

Effectiveness of measles vaccination for control of exposed children

The effectiveness of measles vaccine for postexposure prophylaxis at educational centers was investigated. A total of 166 children who shared the classroom with 10 confirmed cases during the infectious period of cases were studied. Of total susceptible exposed children, 72% (54/75) were vaccinated and 25 contracted measles. Vaccine effectiveness in children vaccinated within 72 hours of exposure was 90.5% (95% confidence interval, 34%–99%).

Predictors of the survival of AIDS cases in Barcelona, Spain

Factors influencing the outcome of disease were analysed in 289 adults presenting with AIDS in Barcelona, Spain from January 1986 (31 cases) to December 1987 (258 cases). One hundred and fifty-four (53.3%) were parenteral drug addicts and 100 (34.6%) were male homosexuals. Ninety-six (33.2%) presented with tuberculosis, 148 (51.2%), with other opportunistic infections, 34 (11.7%) with Kaposis sarcoma, and the remaining 11 with a lymphoma. By February 1988, 144 (49.8%) of the 289 had died, with an actuarial survival probability of 46.7% at 2 years (40.7%-52.7%, 95% confidence interval). The factors selected by the multivariate analysis as independently worsening the prognosis were: having been diagnosed as having AIDS before 1986, being more than 45 years old, not being a parenteral drug addict and presenting with an opportunistic infection other than a tuberculosis or with a malignancy. In conclusion, some factors influencing the prognosis for AIDS patients are very dependent upon the geographical area of the series.

Vaccine Failures in Patients Properly Vaccinated with 13-Valent Pneumococcal Conjugate Vaccine in Catalonia, a Region with Low Vaccination Coverage.

Vaccine failures occurring with 13-valent pneumococcal conjugate vaccine (PCV13) in 3 pediatric hospitals in Barcelona (2012–2013) are described. PCV13 vaccine failure was defined as the occurrence of an invasive pneumococcal infection in children properly vaccinated by PCV13. Among 84 patients with invasive pneumococcal infection, 32 had received at least one dose of PCV13. Seventeen of them had invasive pneumococcal infection produced by a PCV13 serotype. Among those, 9 patients were considered to have a PCV13 vaccine failure. Serotype 3 was isolated in 6 patients, serotype 19A in 2 and serotype 6B in 1.

Measles antibodies and response to vaccination in children aged less than 14 months: implications for age of vaccination.

Passive immunity against measles decreases during the first months of life. The objective of this study was to determine titres of measles antibodies in children aged 9-14 months and their mothers before vaccination, and the childrens response to vaccination. Blood samples were collected by capillary puncture before and 28 days after vaccination. Samples were obtained between February and June 2007 during an ongoing measles outbreak. Titres of specific measles IgG antibodies were determined by enzyme-linked immunosorbent assay. Seroconversion was defined as the presence of antibodies after vaccination in subjects without antibodies before vaccination. Maternal antibodies were present in 37·7% of all 69 children included and in 45·1% of children aged 9 months. Of the 51 children in whom a second sample was obtained, 31 (60·8%) were seronegative before vaccination and 61·3% seroconverted. Interference of maternal antibodies was 30%. Advancing the first dose of measles vaccination from 15 to 12 months is a correct strategy, given the increase in the time of susceptibility of infants to measles.

Validity of self-reported pneumococcal vaccination status in the elderly in Spain.

The objective of this study was to evaluate the validity of information reported by the elderly on 23-valent pneumococcal polysaccharide vaccine (23vPPV) vaccination status. A cross-sectional, observational study was carried out in patients aged >or=65 years admitted to five Spanish hospitals. Data on 23vPPV vaccination history were obtained through interview of the patient or close relative and review of written medical information. The validity of the patient self-report was compared to the written medical information by calculation of the sensitivity, specificity, concordance, positive predictive value (PPV) and negative predictive value (NPV). A total of 2484 patients were initially included of whom 1814 patients (73%) responded about their vaccination status. The global sensitivity of the patient self-report was 0.74 and the specificity 0.95. The PPV was 0.92, the NPV 0.84 and the concordance 87. Vaccination cards and centralized vaccination registries in primary health care centres and hospitals should be potentiated in order to ensure that neither more nor less vaccinations are administered than are necessary.