A. Domínguez

Effectiveness of a mass hepatitis A vaccination program in preadolescents.

A program of mass hepatitis A+B vaccination in preadolescents in schools was begun in the Catalonia in the last quarter of 1998. This study investigated the impact of the program by comparing the incidence of hepatitis A in vaccinated and unvaccinated cohort. The greatest reduction of the incidence rate of hepatitis A was observed in the 10-14 years age group, from 10.3 per 100000 persons-year in the period 1996-1998 to 1.8 per 100000 persons-year in the period 1999-2001. The global incidence decreased from 6.2 to 2.6 per 100000 persons-year. After analysis of cases occurring in the vaccinated and non vaccinated cohort, the effectiveness of the vaccination program was estimated at 97.0% (95% CI: 78.6-99.6).

Importance of sexual transmission of hepatitis C virus in seropositive pregnant women: A case‐control study

The mode of hepatitis C virus (HCV) transmission in patients who deny parenteral exposure is still not understood. Seroprevalence studies of anti‐HCV in sexually promiscuous populations and in spouses of infected patients have given contradictory results. We investigated the role of sexual transmission of HCV in a case‐control study of risk factors for infection in a series of 43 anti‐HCV positive pregnant women and 172 matched controls (4 for each case). In the univariate analysis, the following factors were associated significantly with anti‐HCV seropositivity: low social class, unmarried, history of abortion, wounds which were sutured, tattooes, sharing toiletries with the partner, sexual contact outside the partnership without condom use, blood transfusion, and intravenous drug abuse, but only the last 3 factors remained significantly associated with HCV infection in multiple logistic regression analysis. The relative risk of HCV infection increased according to the increased number of sexual partners. Thus sexual transmission must be considered a possible mode of infection in HCV infected persons without parenteral exposures. J. Med. Virol. 52:164–167, 1997.

An outbreak of food poisoning due to a genogroup I norovirus.

Norovirus infection is associated with approximately 90% of epidemic non-bacterial acute gastroenteritis. The objective of this study is to describe an outbreak of norovirus genogroup I gastroenteritis which affected workers in a hospital and was attributed to food prepared by an infected food handler. Forty cases were detected, of whom 80% were interviewed. The index case was the cook employed in the hospital cafeteria. The following symptoms were observed: abdominal pain in 90.6%, vomiting in 71.9%, diarrhoea in 71.9%, general indisposition in 62.5%, headaches in 53.1% and fever in 32.4% of cases. The initial symptoms were abdominal pain in 37% and vomiting in 28%. Of the 14 samples analysed by RT-PCR, 12 (86%) were positive for a genogroup I norovirus. After sequencing the strain was identified as genotype Desert Shield. Many of the foodstuffs consumed were made by hand, favouring transmission from the index case to the cafeteria users.

Dramatic decline of serogroup C meningococcal disease in Catalonia (Spain) after a mass vaccination campaign with meningococcal C conjugated vaccine

In the last quarter of the year 2000, the meningococcal C conjugated vaccine was incorporated into the routine vaccination schedule in Catalonia (at 2, 4 and 6 months). In addition a vaccination campaign was carried out in children <6 years of age, with a coverage of 96.2%. The effectiveness of the vaccination in this age group during 2001 and the first 28 weeks of 2002 was 100% (94.27-100%). A vaccination campaign has been carried out in 6-19-year olds during 2001 and 2002, with a coverage rate of 23.5% in the year 2001. In this age group a reduction in disease incidence was seen in the 2000-2001 season, but not in the following one.

The seroepidemiology of B. pertussis infection in Catalonia, Spain

A survey of the seroprevalence of pertussis antibodies in a representative sample of the population from Catalonia was carried out. Ninety-seven municipalities and 30 schools were randomly selected to recruit the 2126 subjects who participated in the study. A serum sample was obtained from all individuals participating in the study in order to determine levels of pertussis toxin (PT) and filamentous hemagglutinin (FHA) antibodies by ELISA test. Sociodemographic data were collected for all subjects. The prevalence of PT antibodies was 75% and that of FHA antibodies 89%. Significant increments were observed with age, both in the prevalence of PT (P < 0.0001) and of FHA (P = 0.018). Of the sociodemographic variables studied, only urban habitat was significantly associated to PT antibodies. The agreement observed among the two types of antibodies studied was weak (K = 0.264). Routine revaccination with the acellular vaccine in children over 7 years of age, in adolescents and adults seems a reasonable strategy to prevent the appearance of cases of pertussis in the community.

Impact of mass vaccination with polysaccharide conjugate vaccine against serogroup C meningococcal disease in Spain

During the fourth quarter of 1997, a vaccination campaign using the meningococcal C polysaccharide vaccine was carried out in 14 autonomous regions of Spain. The remaining three regions did not participate. In the last quarter of the year 2000, a mass vaccination campaign using the meningococcal C conjugated vaccine was carried out in all regions. In the year 2001 the incidence decreased in all regions, although the decrease was greater in regions that did not vaccinate in 1997. In contrast, case fatality rates did not decrease. During 2001, the incidence rate of meningococcal C disease was still lower (0.32 per 100000 persons-year) in the regions that vaccinated in 1997 with the polysaccharide vaccine than in those that did not (0.64 per 100000 persons-year).

Measles immunity and vaccination policy in Catalonia

The prevalence of antibodies against measles in a representative sample of the school population in Catalonia was established and the results compared with previous studies. The study was carried out in 1996 using blood samples obtained from schoolchildren aged 6-7 years, 10-11 years, 13 14 years and 15-16 years. 1231 schoolchildren were studied. The global prevalence of antibodies was 96.3%, and a considerable increase was observed with respect to the prevalence in 1986 (89.4%). The level of antibodies was 94% at 6-7 years and 10-11 years, 99.7% at 13-14 years and 98.3% at 15 16 years. These data would suggest the advancement of the administration of the second dose of measles-mumps rubella vaccine to 4 6 years instead of at 11 years.

Waterborne epidemic outbreak of Shigella sonnei gastroenteritis in Santa Maria de Palautordera, Catalonia, Spain

In August 2002 an outbreak of Shigella sonnei infection occurred in a Spanish town of 6343 inhabitants. In total, 756 people developed acute gastroenteritis and 181 cases were shigella-confirmed. The peak incidence was during 5-6 August 2002. The estimated primary attack rate was 9.97%; the attack rate for secondary cases was 38%. The <15 years ago group was most affected (16.49%). The town and its surroundings were served by two water systems, A and B. The cases had consumed water provided by system A (attack rate 164 cases/1000 population). Microbiological analysis of water from system A did not show the presence of coliform bacteria or shigella. This shigellosis outbreak was the largest reported in Spain. The impact of the epidemic was probably greater than the incidence detected.

Brote de gastroenteritis por Norovirus causado por el consumo de agua de suministro público

Introduccion. El objetivo fue investigar un brote de gastroenteritis por Norovirus originado por el consumo de agua de suministro publico. nnMetodos. La primera semana despues de las vacaciones de verano se detecto un brote de gastroenteritis en la escuela publica de Les Borges Blanques (Lleida). Se realizo un estudio de cohortes retrospectivo. Se tomaron muestras de agua y se determino la presencia del ARN de Norovirus (reaccion en cadena de la polimerasa previa transcripcion inversa [PCR-RT]) en las muestras de seis pacientes. El riesgo de gastroenteritis se determino con el riesgo relativo ajustado (RRa) y su intervalo de confianza (IC) del 95%. nnResultados. La tasa de ataque global fue del 45% (96/213). Los sintomas mas frecuentes fueron: abdominalgias, el 88,4% (84/95); nauseas, el 65,9% (62/94), y vomitos, el 64,6% (62/96). El consumo de agua procedente del deposito, el cual estaba en malas condiciones higienicas, se asocio con el riesgo de gastroenteritis (RRa: 2,8; IC 95%: 1,3-6,2), aunque esta agua fue calificada como potable. En las seis muestras de heces se detecto Norovirus. nnDiscusion. Norovirus causo un brote originado por agua calificada como potable. Se recomienda limpiar los depositos de agua despues de las vacaciones estivnnIntroduccion. El objetivo fue investigar un brote de gastroenteritis por Norovirus originado por el consumo de agua de suministro publico. nnMetodos. La primera semana despues de las vacaciones de verano se detecto un brote de gastroenteritis en la escuela publica de Les Borges Blanques (Lleida). Se realizo un estudio de cohortes retrospectivo. Se tomaron muestras de agua y se determino la presencia del ARN de Norovirus (reaccion en cadena de la polimerasa previa transcripcion inversa [PCR-RT]) en las muestras de seis pacientes. El riesgo de gastroenteritis se determino con el riesgo relativo ajustado (RRa) y su intervalo de confianza (IC) del 95%. nnResultados. La tasa de ataque global fue del 45% (96/213). Los sintomas mas frecuentes fueron: abdominalgias, el 88,4% (84/95); nauseas, el 65,9% (62/94), y vomitos, el 64,6% (62/96). El consumo de agua procedente del deposito, el cual estaba en malas condiciones higienicas, se asocio con el riesgo de gastroenteritis (RRa: 2,8; IC 95%: 1,3-6,2), aunque esta agua fue calificada como potable. En las seis muestras de heces se detecto Norovirus. nnDiscusion. Norovirus causo un brote originado por agua calificada como potable. Se recomienda limpiar los depositos de agua despues de las vacaciones estivnIntroduccion. El objetivo fue investigar un brote de gastroenteritis por Norovirus originado por el consumo de agua de suministro publico. nnMetodos. La primera semana despues de las vacaciones de verano se detecto un brote de gastroenteritis en la escuela publica de Les Borges Blanques (Lleida). Se realizo un estudio de cohortes retrospectivo. Se tomaron muestras de agua y se determino la presencia del ARN de Norovirus (reaccion en cadena de la polimerasa previa transcripcion inversa [PCR-RT]) en las muestras de seis pacientes. El riesgo de gastroenteritis se determino con el riesgo relativo ajustado (RRa) y su intervalo de confianza (IC) del 95%. nnResultados. La tasa de ataque global fue del 45% (96/213). Los sintomas mas frecuentes fueron: abdominalgias, el 88,4% (84/95); nauseas, el 65,9% (62/94), y vomitos, el 64,6% (62/96). El consumo de agua procedente del deposito, el cual estaba en malas condiciones higienicas, se asocio con el riesgo de gastroenteritis (RRa: 2,8; IC 95%: 1,3-6,2), aunque esta agua fue calificada como potable. En las seis muestras de heces se detecto Norovirus. nnDiscusion. Norovirus causo un brote originado por agua calificada como potable. Se recomienda limpiar los depositos de agua despues de las vacaciones estivnIntroduccion. El objetivo fue investigar un brote de gastroenteritis por Norovirus originado por el consumo de agua de suministro publico. nnMetodos. La primera semana despues de las vacaciones de verano se detecto un brote de gastroenteritis en la escuela publica de Les Borges Blanques (Lleida). Se realizo un estudio de cohortes retrospectivo. Se tomaron muestras de agua y se determino la presencia del ARN de Norovirus (reaccion en cadena de la polimerasa previa transcripcion inversa [PCR-RT]) en las muestras de seis pacientes. El riesgo de gastroenteritis se determino con el riesgo relativo ajustado (RRa) y su intervalo de confianza (IC) del 95%. nnResultados. La tasa de ataque global fue del 45% (96/213). Los sintomas mas frecuentes fueron: abdominalgias, el 88,4% (84/95); nauseas, el 65,9% (62/94), y vomitos, el 64,6% (62/96). El consumo de agua procedente del deposito, el cual estaba en malas condiciones higienicas, se asocio con el riesgo de gastroenteritis (RRa: 2,8; IC 95%: 1,3-6,2), aunque esta agua fue calificada como potable. En las seis muestras de heces se detecto Norovirus. nnDiscusion. Norovirus causo un brote originado por agua calificada como potable. Se recomienda limpiar los depositos de agua despues de las vacaciones estiv

Prevalence of Neisseria meningitidis carriers in the school population of Catalonia, Spain.

The aim of this study was to determine the prevalence of healthy Neisseria meningitidis pharyngeal carriers in a representative sample of the Catalonian school population, as well as its associated factors. The sample was divided into age groups: < or = 5, 6-7 and 13-14 years old. Parents were given a questionnaire to collect information on sociodemographic and epidemiological variables. Oropharyngeal swabs were collected with a cotton-tipped swab in an Amies transport medium and cultured on Thayer Martin plates at 35 degrees C in 5% CO2. The isolates were serogrouped and sero/subtyped. Of the 1406 children studied, 75 (5.34%) meningococcal carriers were detected: 63 B (4.5%), 9 non groupable (0.7%), 2 29E (0.1%) and 1X (0.07%). No serogroup C meningococci were found in this study, probably due to the high A+C vaccination coverage of up to 68.9% in children 6-7 years old. Bivariate analysis identified six statistically significant risk factors for meningococcal carriage: increasing age, recent upper respiratory tract infection, previous antibiotic treatment, number of students in the class, size of the classroom and social class. Multivariate analysis found that only age and previous antibiotic treatment remained statistically significant when the other factors were controlled.